THE CHEMISTRY OF 1,2-DIHYDRO-l,2-AZABORlNE AND NITRATED LIPIDS by ADAM JOHN VON MARWITZ A DISSERTATION Presented to the Department of Chemistry and the Graduate School of the University of Oregon in partial fulfillment of the requirements for the degree of Doctor of Philosophy September 2010 ii University of Oregon Graduate School Confirmation of Approval and Acceptance of Dissertation prepared by: Adam Marwitz Title: "The Chemistry of 1,2-Dihydro-l ,2-azaborine and Nitrated Lipids" This dissertation has been accepted and approved in partial fulfillment of the requirements for the degree in the Department of Chemistry by: Michael Haley, Chairperson, Chemistry Shih-Yuan Liu, Advisor, Chemistry David Tyler, Member, Chemistry Raghuveer Parthasarathy, Outside Member, Physics and Richard Linton, Vice President for Research and Graduate Studies/Dean of the Graduate School for the University of Oregon. September 4, 2010 Original approval signatures are on file with the Graduate School and the University of Oregon Libraries. III An Abstract of the Dissertation of Adam John Von Marwitz for the degree of Doctor of Philosophy in the Department of Chemistry to be taken September 20 I0 Title: THE CHEMISTRY OF 1,2-DIHYDRO-I,2-AZABORINE AND NITRATED LIPIDS Approved: _ Professor Shih-Yuan Liu 1,2-Dihydro-I,2-azaborine is a six-membered aromatic heterocycle that is related to the quintessential aromatic molecule, benzene, via the replacement of a CC fragment in benzene with an isoelectronic BN bond-pair. Like the benzene motif, 1,2-dihydro-I,2- azaborine derivatives could provide opportunities in fields ranging from medicine to materials. Recent breakthroughs in the synthesis of I ,2-dihydro-1 ,2-azaborine have led to a burgeoning interest in this relatively unexplored heterocycle. This dissertation describes the synthesis, characterization, and potential applications of novel 1,2-dihydro- 1,2-azaborines. Chapter I reviews the chemistry of monocyclic and polycyclic BN- heterocycles over the last fifty years. Chapter II introduces the synthesis of numerous boron-substituted I,2-dihydro-1 ,2-azaborine derivatives from a versatile precursor. Chapter III discusses the first successful synthesis of the parent 1,2-dihydro-l ,2- azaborine, which is isoelectronic with benzene itself. An examination of the chemistry of 1,2-dihydro-l ,2-azaborine provides a direct comparison of its properties relative to benzene. Chapter IV discusses the synthesis and characterization of 1,2-dihydro-l ,2- azaborines incorporated into phenylacetylenic scaffolds. Chapter V discusses unrelated work on nitrated lipids, which was performed under the guidance of Professor Bruce Branchaud. The chapter introduces the importance of nitrated lipids in a biological context and details the synthetic achievements in this field. This dissertation includes previously published and unpublished co-authored material. IV CURRICULUM VITAE NAME OF AUTHOR: Adam John Von Marwitz GRADUATE AND UNDERGRADUATE SCHOOLS ATTENDED: University of Oregon, Eugene, Oregon The Colorado School of Mines, Golden, Colorado DEGREES AWARDED: Doctor of Philosophy in Chemistry, 2010, University of Oregon Master of Science in Chemistry, 2005, University of Oregon Bachelor of Science in Chemical Engineering, 2004, The Colorado School of Mines AREAS OF SPECIAL INTEREST: Aromatic boron heterocycles Nitrated lipids PROFESSIONAL EXPERIENCE: Graduate Research Assistant, Department of Chemistry, University of Oregon, Eugene, Oregon, 2005-2010. Graduate Teaching Assistant, Department of Chemistry, University of Oregon, Eugene, OR, 2004-2005. v VI GRANTS, AWARDS AND HONORS: National Science Foundation IGERT Fellowship, 2008-2009 PUBLICATIONS: Daly, A. M.; Tanjaroon, C.; Marwitz, A 1. V.; Liu, S. - Y.; Kukolich, S. G. "Microwave Spectrum, Structural Parameters, and Quadrupole Coupling for 1,2-Dihydro-1 ,2- azaborine," JAm. Chem. Soc. 2010,132,5501-5506. Marwitz, A J. V.; McClintock, S. P.; Zakharov, L. N.; Liu, S. -Yo "BN Benzonitrile: An Electron-deficient 1,2-Dihydro-1,2-azaborine Featuring Linkage Isomerism," Chern. Comm. 2010,46, 779-781. Tanjaroon, C.; Daly, A; Marwitz, A J. V.; Liu, S. -Y.; Kukolich, S. "Microwave Measurements and Ab Initio Calculations of Structural and Electronic Properties ofN- Ethyl-1,2-azaborine," J Chem. Phys. 2009,131,22431211-224312/9. Liu, L.; Marwitz, A. J. V.; Matthews, B. W.; Liu, S. -Y. "Boron Mimetics: 1,2-Dihydro- 1,2-azaborine Binds inside a Non-polar Cavity ofT4 Lysozyme," Angew. Chem. Int. Ed. 2009,48,6817-6819. Marwitz, A J. V.; Matus, M. H.; Zakharov, L. N.; Dixon, D. A; Liu, S. -Y. "A Hybrid Organic/inorganic Benzene," Angew. Chem. Int. Ed. 2009,48,973-977. Marwitz, A. 1. V.; Abbey, E. R.; Jenkins, J. T.; Zakharov, L. N.; Liu, S. -Y. "Diversity though Isosterism: The Case of Boron-substituted 1,2-Dihydro-1 ,2-azaborines," Org. Lett. 2007, 9, 4905-4908. Woodcock, S. R.; Marwitz, A 1. V.; Bruno, P.; Branchaud, B. P. "Synthesis ofNitro- lipids. All Four Possible Diastereomers ofNitro-oleic Acids: (E)- and (Z)-, 9- and 10- Nitro-octadec-9-enoic Acids," Org. Lett. 2006, 8, 3931-3934. VB ACKNOWLEDGMENTS I would like to sincerely thank my research advisor, Professor Shih-Yuan Liu, for his continued support and guidance over the last four years. I would also like to thank Professor Bruce Branchaud for the opportunity to work in his group. I would like to extend a special thank you to my committee chair, Professor Michael M. Haley, for his continued support during my graduate career. I would like to acknowledge my other committee members, Professor David R. Tyler, Professor Raghu Parthasarathy, Professor Nathan Tublitz, and Professor Bea Darimont for their advice and scientific input concerning my research. Dr. Lev Zakharov for his crystallographic expertise. Dr. Bartholemew Dahl and Dr. Steven Woodcock for their mentorship during my time in the Branchaud group. Eric Abbey for providing camaraderie and scientific input to a fledgling project in the Liu group. Adam Glass, Pat Campbell, Ashley Lamm, Jesse Jenkins, Jed Volvovic, and Dr. Tshitij Parab for contributing greatly to my research. Dr. Justin Crossland and Dr. Tim Carter for their friendship. My family for their love and support. I would also like to thank every person who has provided assistance throughout my graduate career. There are too many to be named here. Finally, I would like to thank the National Science Foundation IGERT program for over a year of funding. For my loving wife Katie. V111 IX TABLE OF CONTENTS Chapter Page 1. THE CHEMISTRY OF HYBRID BORON-NITROGEN HETEROCYCLES 1 1.1. Introduction..................................................................................................... 1 1.2. C4BN Heterocycles......................................................................................... 3 1.2.1. Synthesis of Monocyclic 1,2-Azaborine Derivatives............................ 3 1.2.2. Computational Studies on I,2-Azaborine Derivatives........................... 19 1.2.3. Bicyclic [4.4.0] C4BN Derivatives......................................................... 31 1.2.4. Additional C4BN-Containing Bicyclic Motifs....................................... 46 1.2.5. Tricyclic C4BN-Containing Motifs........................................................ 50 1.2.6. Tetracyclic Analogs 60 1.2.7.1,3- and I,4-Substituted C4BN Heterocycles......................................... 63 1.3. The Diazadiborine Motif as a Benzene Analog 67 1.3.1. Isomers of Diazadiborine...................................................... 67 1.3.2. 1,3-Diaza-2,4-diborines 68 1.3.3. I,4-Diaza-2,3-diborines 71 1.3.4. 2,3-Diaza-I,4-diborines 73 1.3.5. I,3-Diaza-4,6-diborines 75 1.3.6. Non-aromatic Analogs of 1,3-Diaza-2,5-diborine and I,4-Diaza-2,5-diborine..................................................................................... 76 1.4. Summary 81 Chapter Page x 1.5. Bridge to Chapter II 82 II. EXPANDING THE SCOPE OF 1,2-AZABORINE SYNTHESIS VIA NUCLEOPHILIC SUBSTITUTION AT BORON................................................. 84 2.1. General Overview............................................................... 84 2.2. Introduction..................................................................................................... 85 2.3. Generation of a Versatile 2-Chloro-l ,2-azaborine....................... 87 2.4. The Synthesis and Coordination Chemistry ofBN-benzonitrile.................... 91 2.5. Cationic B-Substituted 1,2-Azaborines 98 2.6. Substituent Effects in Neutral 1,2-Azaborines................................................ 108 2.7. Conclusion 119 2.8. Bridge to Chapter III 120 III. SYNTHESIS AND CHARACTERIZATION OF 1,2-DIHYDRO- 1,2-AZABORINE 121 3.1. General Overview........................................................................................... 121 3.2. Introduction 122 3.3. Synthesis and Characterization of 1,2-Dihydro-l ,2-azaborine....................... 124 3.4. Microwave Spectroscopy of 1,2-Dihydro-l ,2-azaborine................................ 136 3.5. 1,2-Azaborine Protein Binding 138 3.6. Conclusion 141 3.7. Bridge to Chapter IV 142 Chapter Xl Page IV. 1,2-DIHYDRO-1,2-AZABORINE IN CONJUGATED PHENYLACETYLENIC SCAFFOLDS 143 4.1. General Overview 143 4.2. Introduction 143 4.3. Synthesis ofBN Tolan Derivatives 145 4.4. Diyne Scaffolds with a 1,2-Azaborine Core 152 4.5. Conclusion 164 4.6. Bridge to Chapter V.................................................................................. 164 V. SYNTHESIS OF NITROLIPIDS 165 5.1. General Overview 165 5.2. Introduction 165 5.3. Synthesis of All Four Diastereomers of Nitrooleic Acid 167 5.4. Synthesis of Nitrolinoleic Acid Analogs 172 5.5. Conclusion 176 APPENDICES 177 A. SYNTHESIS AND CHARACTERIZATION OF BORON-SUBSTITUTED 1,2-AZABORINES 177 B. SYNTHESIS AND CHARACTERIZATION OF 1,2-DIHYDRO- 1,2-AZABORINE 305 C. SYNTHESIS AND CHARACTERIZATION OF TOLAN ANALOGS AND DIYNE SCAFFOLDS 359 D. SYNTHESIS AND CHARACTERIZATION OF NITROLIPIDS 432 Chapter XlI Page BIBLIOGRAPHY 442 Xlll LIST OF FIGURES Figure Chapter I Page 1. Isoelectronic relationship between CC and BN 2 2. 1,2-Dihydro-l ,2-azaborine 1 is isoelectronic with benzene..... 3 3. The Jt-molecular orbitals for benzene, borazine, and 1 23 4. 13C and 11B chemical shifts for 1 calculated via IGLO DZ and IGLO II' 25 5. Dehydrogenation/hydrogenation of 1,2-dihydro-l ,2-azaborine 25 6. Bridged chloronium 64 in the chlorination of 1,2-azaborine................................. 26 7. Physisorption of Hz with MOF model compound 65 27 8. Face- and edge-site adsorption of Hz with 1 and benzene 28 9. BN-Benzyne 66 is isoelectronic with benzyne 28 10. Ring strain energies for cycloiminoborane 67 and its carbon analog 29 11. Representation of the structures of the transition state for the Diels-Alder reaction of 16 and butadiene 30 12. All 6 isomers ofBN-naphthalene 32 13. Relative stabilities of BN-naphthalene isomers..... 46 14. Tautomerism in 7,8-substituted BN-indene........................................................... 50 15. BN-Quinazoline 152 50 16. Chlorination and nitration products ofBN-phenanthrene 52 17. Trimerization ofBN-phenanthrene with a borazine core 54 Figure XIV Page 18. Hydrogen-bonding of 154 in the solid-state 55 19. BN-Acenaphthalene derivative with bridgehead B-N substitution 60 20. Tetracyc1ic analogs of aromatic hydrocarbons containing the B-N bond unit 61 21. Crystal packing in BN-pyrene 191 62 22. Quinoline-substituted BN-heterocycle 193............................................................ 63 23. BN-Fluoranthrene 194 63 24. Azaborine isomers 64 25. All possible isomers of diazadiborine.................................................................... 68 26. Phenanthrene derivatives containing the I,3-diaza-2,4-diborine unit 70 27. I,4-Diaza-2,3-diborine analogs of polycyclic aromatic hydrocarbons.................. 72 28. I,4-Diaza-2,3-diborine 217 containing the B-B bond 72 29. Ring-fused and bicyclic isomers oftetraaminodiborane 72 30. Saturated I,4-diaza-2,3-diborocyclohexane 235.................................................... 77 31. Head-to-tail dimerization of CN groups to generate 1,4-diaza-2,5-diborine ......... 78 32. Isomerization in the dimerization of2-pyridyl boranes......................................... 80 Chapter II 1. Benzonitrile and isoelectronic I,2-azaborine analog............................... ......... ...... 91 2. Electrostatic potential maps for I,2-azaborines 10 and 6i...................................... 93 3. HOMO and LUMO of 10 calculated at the B3LYP/DGDVP2Ievel...................... 95 4. ORTEP illustration of 12 97 Figure xv Page 5. ORTEPillustrationof14a 101 6. ORTEP illustration of 14b 102 7. ORTEP illustration of 14c 103 8. ORTEP illustration of 14d 103 9. Normalized absorption spectra for pyridine-substituted 1,2-azaborine cations...... 107 10. Absorption and emission spectra of 14a in CH2Ch and MeCN 107 11. ORTEP illustration of7 110 12. ORTEP illustrationof6h 110 13. ORTEP illustration of6g 111 14. ORTEP illustrationof15 113 15. ORTEP illustration of 18 114 16. ORTEP illustrationof19 115 17. ORTEP illustration of20 116 18. Geometric orientation of the N-ethy1 substituent in 1,2-azaborines 117 19. Relative rates ofbromination for B-substituted 1,2-azaborines 119 Chapter III 1. Benzene, borazine, and 1,2-dihydro-1 ,2-azaborine 1 123 2. IH NMR spectrum of 1 in CD2Ch 129 3. Absorption spectra of 1, benzene, and borazine 130 4. ORTEP illustration of 13 135 Figure XVI Page 5. HOMO of 1,2-dihydro-l,2-azaborine 136 6. Geometric and electronic features of 1 via microwave spectroscopy 138 7. 1,2-Dihydro-l,2-azaborine 1, N-ethyl-l,2-azaborine 15, and carbon analogs 139 8. Difference maps for the binding of 15 and ethylbenzene 140 9. Difference maps for the binding of 1 and benzene................................................. 141 Chapter IV 1. Derivatives of toIan containing the 1,2-azaborine ring 144 2. ORTEP illustration of 1 147 3. ORTEP illustration of2 148 4. ORTEP illustrations of interactions in BN tolan 2 149 5. Absorption spectra for 1, 2, and diphenylacetylene 150 6. Normalized emission spectra for 1, 2, and tolan 151 7. Normalized emission spectra of2 in various solvents 151 8. 1,2-Azaborine 12 152 9. Absorption and emission spectra of 12 155 10. Conjugation pathways in 17, 18, and carbon analog 19 156 11. Normalized absorption spectra for 12, 17, and 18................................................. 161 12. Normalized emission spectra for 12,17, and 18 161 13. 1,2-Azaborines 26 and 27 162 Figure xvii Page Chapter V 1. (E)-Isomers of nitrooleic acid and nitrolinoleic acids............................................. 166 2. Biologically relevant Michael addition to nitroalkenes 166 3. 13-Nitrolinoleic acid 17 172 4. Model compounds 18 and 19 172 XVlll LIST OF TABLES Table Chapter I Page 1. IIBNMR Shifts ofw-ArninoboronicEsters........................ 8 2. Selected Bond Distances for 42 and 43 13 3. Selected Bond Distances and Deviations from Planarity for Heterocycles 50-54 17 4. Geometric Parameters of 1..................................................................................... 20 5. a and :;rt Energy Levels for 1 21 6. Electronic and Structural Parameters of 1 by Ml\TDO 23 7. Thermochemical Reactions and Energies at RHF/6-31G* 24 8. Adsorption Energies for H2 Loading in benzene and 1 28 9. Electronic Features ofBN-Naphthalene Isomers 46 10. Absorption-Emission Properties ofBN-Phenanthrene 57 11. Photophysical Properties of BN-Acenes................................................................ 67 Chapter II 1. Survey of Aromatization Conditions for Heterocycle 2 88 2. Synthesis ofB-Substituted 1,2-Azaborines from 3................................................ 90 3. IH and B C NMR Shifts ofB-Substituted 1,2-Azaborines..................................... 94 4. Synthesis of 1,2-Azaborine Cations....................................................................... 100 Table XIX Page 5. Structural and Electronic Properties for Pyridine-substituted 1,2-Azaborines ...... 106 Chapter III 1. Survey of Debenzylation Conditions for Heterocycle 2........................................ 125 2. Magnetic and Energetic Data for Benzene, 1, and Borazine 132 Chapter IV 1. Photophysical Data for Compounds 17, 18, 26, and 27......................................... 163 xx LIST OF SCHEMES Scheme Page Chapter I 1. Synthesis of 3. 4 2. Dehydrogenation route to 5 4 3. Hydroboration-oxidation protocol leading to 7 4 4. Hydroboration to 8................................................................................................. 5 5. Hydroboration-oxidation to generate 10 5 6. Desulfurization ofBN-benzothiophenes................................................................ 6 7. [4+2] Cycloaddition of 16....................... 7 8. Ene-type reaction of 16 7 9. Intramolecular cyclization of w-aminoboronic esters............................................ 8 10. Reaction of21 with benzyl azide and HCI............................................................ 9 11. Formation of 24 and 25...................................... 9 12. Synthesis of 30 via ring-closing metathesis........................................................... 10 13. Ring-expansion route to I,2-azaborines 34a-c 10 14. Formation ofYJ6 complexes of I,2-azaborines....................................................... 11 15. The reversible deprotonation of5 and 41.............................................................. 12 16. Switchable haptotropic migrations of the 2-phenyl-I,2-azaborine ligand............. 13 17. Formation of 44...................................................................................................... 14 Scheme xxi Page 18. Synthesis of complexes 46 and 47 15 19. EAS reactivity of39............................................................................................... 16 20. Resonance stabilization of 3- and 5-substituted 1,2-azaborine.............................. 16 21. Catalytic formation of 50-54 :.. 17 22. Hydrogen storage by CBN heterocycles................................................................ 18 23. Partial regeneration of 1,2-azaborine spent fuel..................................... 19 24. Sequential addition ofH-/H+ across the B-N bond................................................ 19 25. Mild route to fully-charged cyclic aminoborane fuels........................................... 19 26. Proposed reaction pathways in the nitration of 1,2-azaborines at C3.................... 26 27. Regioselectivity in the [4+2] cycloaddition of 16 31 28. [2+2] and [4+2] reactivity of 71 31 29. Synthesis of B-substituted 1,2-azaboronaphthalenes............................................. 33 30. Comparison of hydrolytic stability of 75 versus reduced anhydride 77................ 33 31. EAS reactivity of 76........... 34 32. Synthesis of water-soluble BN-naphthalenes 35 33. Synthesis of bridgehead BN-naphthalene 92......................................................... 35 34. Synthesis of 94 and 95 36 35. Formation of94 from 92........................................................................................ 37 36. Cyclization to 96 38 37. Formation of piano-stool complex 101.................................................................. 38 38. Haptotropic migration in 102................................................................................. 39 Scheme XXll Page 39. Haptotropic migration in B-methyll,2-azaboronaphthalene 40 40. Ring-expansion or BN-indene to 92 41 41. Pd-catalyzed ring-closure to 116........................................................................... 41 42. 2,I-Substituted BN-heterocycles 42 43. Hydroboration of 121 to 120.................................................................................. 42 44. Synthesis ofterpenoid BN-heterocycle 124 43 45. Kinetic resolution of racemic lactone 126 with amine-borane 125....................... 44 46. Photocyclization of vinylborane 127 44 47. Synthesis of 130..................................................................................................... 45 48. Cyclization to BN-norbornadiene 133................................................................... 47 49. Synthesis of 138 and coordination chemistry of the BN-indenyI ligand 48 50. Haptotropic migration of the BN-indenylligand................................................... 49 51. Formation of 7,8-substituted BN-indene analogs 50 52. Preparation of 153 and boron-substituted derivatives 51 53. Installation of a 1t-accepting group at the nitrogen of 163..................................... 54 54. Cyclization to 167 56 55. Formation of 168 with an internalized BN bond pair 56 56. Synthesis ofBN-phenanthrene dimers................................................................... 57 57. Photochemical cyclization of aminoboranes to 156 58 58. Condensation route to tricyclic aromatic BN-heterocycles 59 59. Synthesis ofBN-pyrene 191.................................................................................. 62 Scheme XX111 Page 60. Preparation of non-aromatic heterocycle 195 64 61. Synthesis of 196..................................................................................................... 65 62. Synthesis ofBN-pentacene isomers 199 and 201 and BN-heptacene 203 66 63. Synthesis of 205 68 64. Formation ofbenzo-fused 1,3-diaza-2,4-diborine 206 69 65. Condensation to naphthalene analog 207 69 66. Atropisomerism in piano-stool complexes of BN-naphthalene 211...................... 71 67. Synthesis of 2,3-diaza-l ,4-diborines 219-220 and complexes 221-222................ 73 68. Cycloaddition of 223 to derivatives 224 and 225 74 69. Polycyclic aromatic hydrocarbons substituted with a 2,3-diaza-l,4-diborine core......................................................................................................................... 75 70. Synthesis of 1,3-diaza-4,6-diborines 232-234 76 71. Formation of237a and 237b from imidazole-borane 239..................................... 79 72. Ring-opening of 240 with isocyanides 81 Chapter II 1. RCM-oxidation and ring-expansion routes to 1,2-azaborines 86 2. Ring-closing of aminoborane 1 to generate BN-heterocycle 2.............................. 87 3. Purification strategy for 1,2-azaborine 3............................................................... 89 4. Synthesis of 7 90 5. Synthesis ofBN-benzonitrile 10............................................................................ 93 6. Complexation of 10 with chromium(O) 95 Scheme XXiV Page 7. Alternate route to 12 97 8. Strategy for generating cationic 1,2-azaborines..................................................... 98 9. Synthesis of 13....................................................................................................... 99 10. Disruption of aromaticity in substituted BN-heterocycles..................................... 108 11. Synthesis of 1,2-azaborine 15................................................................................ 112 12. Synthesis ofBN-biphenyl19 and BN-tolan 20 114 Chapter III 1. Retrosynthesis of 1 from a versatile 1,2-azaborine intermediate 124 2. Observation ofTMS-protected aminoborane 5 126 3. Formation of TIPS-protected 6 127 4. Synthesis of 1,2-dihydro-l ,2-azaborine 1.............................................................. 128 5. Improved conditions for the isolation of 1.. 128 6. Reaction schemes for the calculation ofRSE in 1 versus benzene 133 7. HID exchange in 1,2-dihydro-l ,2-azaborine 134 8. Exploration of aldehyde reduction using 1,2-dihydro-l ,2-azaborine 134 Chapter IV 1. Synthesis ofBN tolan 1 145 2. Synthesis of bis BN tolan 2........................................................... 146 3. Retrosynthetic analysis of 12 153 4. Synthesis of diyne 12........ 154 Scheme xxv Page 5. Synthesis of 17 157 6. Exploration of cross-coupling toward the synthesis of 18 159 7. Synthesis of 18 160 8. Synthesis of 26 and 27 163 Chapter V 1. Synthesis of nitrated lipids in a non-regioselective manner 167 2. Synthesis of nitroalkane 3.................... 168 3. Synthesis of 1........ 169 4. Synthesis of aldehyde 11 and nitrononane 9 170 5. Synthesis of2 171 6. Isomerization of 1 and 2 to 15 and 16, respectively.............................................. 171 7. Synthesis of 18 173 8. Synthesis of 19 175 9. Synthesis of 33 and 34 176 1CHAPTER I THE CHEMISTRY OF HYBRID BORON-NITROGEN HETEROCYCLES 1.1. Introduction Benzene (c-C6H6) was first isolated from the distillate of coal tar nearly two centuries ago, l yet the study of benzene and its derivatives continues to drive research in the 21 st century. The study of benzene's fundamental properties has given rise to the concept of aromaticity and bond delo~alization. Beyond its fundamental importance, benzene derivatives are commonly found in fields such as polymer science, biomedical research, and material science. Borazine (c-B3N3H6), the inorganic, isoelectronic counterpart to benzene, was isolated by Alfred Stock in 1926,2 and has also received significant attention in pure and applied chemistry. The analogy ofborazine as an "inorganic" benzene is derived from the donation of a lone pair of electrons from nitrogen into the vacant p-orbital of the Sp2_ hybridized boron (Figure 1). The number and geometry of electrons is the same in the B-N and C=C bond units, and therefore borazine and benzene are isoelectronic. On the other hand, borazine tenuously meets the criteria for aromaticity, and its relative instability has limited its utility. 2'c""'" isoelectronic 'N""'" II <¢:=======» I .......C, ....... B, •• ,<±>....... N II .......B, e Figure 1. Isoelectronic relationship between CC and BN. The isoelectronic relationship between B-Nand C=C has led to an emergence of aromatic systems partially substituted with boron and nitrogen (carbon-boron-nitrogen (CBN) heterocycles). Though somewhat limited in scope, the first major achievements in the synthesis of CBN heterocycles took place in the 1960s. After several decades of diminished activity in the field, modem synthetic protocols have promoted a resurgence in the study of CBN heterocycles. This chapter will serve to provide a review of the chemistry of 6-membered heterocycles containing one and two B-N bond units. Aromatic CBN heterocycles isoelectronic with benzene will be of primary interest. Non-aromatic six-membered heterocycles will also be discussed, especially as they relate to the aromatic analogs. Isoelectronic analogs of pyridine, such as BODIPY dyes, will not be discussed but have been reviewed extensively.3-4 Substitution ofB-N units in cluster compounds and graphitic materials is beyond the scope of this review.s This chapter will be organized by heterocyclic motif and will cover both monocyclic and polycyclic derivatives. It will be organized chronologically to give as much historical context as possible with regard to the general periods of CBN heterocycle research, where relevant. Calculations on CBN heterocycles have contributed greatly to the interest in this field, and thus this work will also be discussed in relation to known or predicted physical properties. However, 3an in-depth discussion of calculation methods will not be covered here. Synthetic achievements will be discussed separately from theoretical work as much as possible to avoid confusion. 1.2. C4BN Heterocycles 1.2.1. Synthesis ofMonocyclic 1,2-Azaborine Derivatives 1,2-Dihydro-1 ,2-azaborine (hereafter 1,2-azaborine unless referring to parent compound 1) is a 6 Jt-electron analog of benzene in which a C=C unit has been replaced with a B-N bond pair (Figure 2). 6 15(~,H 4 ~ B'H 3 2 isoelectronic <: :> Benzene1,2-Dihydro- 1,2-azaborine 1 Figure 2. 1,2-Dihydro-l,2-azaborine 1 is isoelectronic with benzene. Dewar and White pioneered the first syntheses ofmonocyclic 1,2-azaborine derivatives. In 1962, Dewar and co-workers used a desulfurization strategy from BN- benzothiophene 2 to generate highly-substituted 1,2-azaborine 3 (Scheme 1).6 Compound 3 was resistant to degradation under prolonged exposure to both acid and base in ethanol as monitored by UV-vis spectroscopy (A.max = 306 nm, E = 15850 M-1cm- 1). Acid/base stability and the inertness of the 1,2-azaborine double bonds toward Raney Nickel are indications of the aromatic stability of the 1,2-azaborine core. A year later, 4White reported the synthesis of I-H-2-phenyl-l,2-azaborine 5 via Pd-catalyzed dehydrogenation from saturated heterocycle 4 (Scheme 2).7 Raney l\Ji Scheme 1. Synthesis of 1,2-azaborine derivative 3 via desulfurization with Raney Nickel (Dewar, 1962). 4 Pd/C 5 Scheme 2. Dehydrogenation route to 1,2-azaborine 5 (White, 1963). In 1967, Dewar and co-workers attempted the first synthesis of 1,2-Dihydro-l,2- azaborine 1 via a hydroboration-oxidation protocol but were unsuccessful.8 They concluded that, "Borazarene [1,2-Dihydro-l,2-azaborine] therefore seems to be a very reactive and chemically unstable system, prone to polymerization and other reactions... " In fact, multiple attempts to isolate the parent 1,2-Dihydro-l,2-azaborine 1 from BN- triphenylene 7 (Scheme 3) were unsuccessful. Pd/C 5Polivka et al. followed a similar route to generate 1,2-azaboracyclohexane 8 from dimethylaminobut-3-ene (Scheme 4).9,10 Alkylation of the amine prevents the trimerization of 8; heterocycle 8 is readily isolated via vacuum distillation. Compound 8 is formally isoelectronic with 1,1-dimethylcyclohexane, and the tetracoordinate boron and nitrogen atoms are unable to participate in n-bonding. Instead the B-N bond pair can be considered a dative a-bond. The generation of a 1,2-azaborine motif from 8 was not observed. Baboulene and co-workers have recently used N-alkyl amine-boranes such as 8 to form aminoalkylboronic acid salts as surfactant materialsY CMe2 Et3 f\I-BH3 • C~~2e2 8 Scheme 4. Hydroboration to stable 1,2-azaboracyclohexane 8. Goubeau and co-workers used a secondary butenyl amine (as in White's earlier work) to form 1,2-azaborine 9 via hydroboration (Scheme 5).12 Dehydrogenation with Pd/Ah03 provided the first B-H substituted 1,2-azaborine 10, which was characterized by mass spectrometry. 13 CI\lHMe Me3N-BH3. C~Me Pd/AI20 3 • (~Me// BH ~ BH 9 10 Scheme 5. Hydroboration-oxidation to generate B-H substituted 1,2-azaborine 10. Gronowitz and co-workers synthesized a series ofBN-benzothiophenes, which upon desulfurization yielded the first examples ofmonocyclic 1,2-azaborines substituted at C4 and/or C5. 14-17 Desulfurization ofBN-benzothiophene 11 generated 1,2-azaborine 12 (Scheme 6) selectively, which reacted further with Raney-Ni to produce the first 1,2- 15 6 azaborine substituted at the C5 position with an aliphatic (ethyl) group (13 in Scheme 6).16 Reaction ofBN-benzodithiophene 14 with Raney-Ni afforded 4,5-diethyl-1,2- azaborine 15.14 wH Raney Ni Et 7' W H Raney Ni Et~~_HI • I .. B"' Ph ::::.... B"' Ph ::::.... B"' Ph ?" ?" BuS S 13 11 12 g:N,H Raney Ni::::.... S"'Ph .. ~ S 14 Scheme 6. Desulfurization ofBN-benzothiophenes with Raney Nickel to generate 4-, and 5-substituted 1,2-azaborines. BUrger and co-workers reported another route to monocyclic 1,2-azaborine derivatives in 1990. 18 The reaction of dialkylaminobis(trifluoromethyl)boranes (e. g. 16 in Scheme 7) with a variety of alkyl-substituted 1,3-dienes led to the formation of a CBN heterocycle (e. g. 17) via a [4+2] cycloaddition. The X-ray crystal structure of 17 revealed a long B-N bond (1.621(3) A) consistent with a a-bonded complex for the tetra- coordinate boron and nitrogen atoms. The reaction of aminoborane 16 to generate cyclic amine-boranes was later accomplished via a two-step substitution sequence (Scheme 8).19 5-Bromopentanenitrile underwent an ene-type reaction to generate ring-opened 18. Deprotonation with KOH led to the intramolecular N-alkylation of 18 to generate nitrile- substituted BN heterocycle 19. Interestingly, in compounds similar to 19, reduction of Me'wMe II FsC... B'CFs 16 7 the nitrile using (iBu)2AlH followed by hydrolysis furnished the corresponding aldehyde, which is a testament to the stability of these compounds. Mex Me'N,Me C Me:c+ II 10 o. I ~Me2 Me FsC... B'CF s Me B(CFsh 16 17 Scheme 7. [4+2] Cycloaddition of aminoborane 16 with a 1,3-diene generates cyclic amine-borane 17. Br Br(CH2)4CN • ~ I\IHMe2 KOH. rl\'Me2 yB(CFsh 'yB(CFS)2 CN CN 18 19 Scheme 8. Ene-type reaction of 16 generates ring-opened 18 which undergoes an intramolecular N- alkylation to give heterocycle 19. In a preparation of w-aminoboronic esters from azides (Scheme 9), Vaultier and co-workers reported liB NMR chemical shifts for compounds 20a-i that indicated a substituent and chain-length dependence on intramolecular cyclization (Table 1).20 The upfield chemical shift in liB NMR spectroscopy of several of these compounds is consistent with an equilibrium between 3- and 4-coordinate boron for the ring-opened and ring-closed forms, respectively (Scheme 9). Mikhailov and co-workers observed temperature-dependence in the equilibrium of intramolecular cyclization of amine- boranes.21 -22 R1RIHN~B(Pin) Rs R2 20 (open) Rs A. H2o Pd/C (~I\IHRI B. 1) R'BCI2 • R2~B(pin) 2) NaOH R 1 20 Rs (~NHRI ____ R2~B(Pin)~ R1 20 (closed) Scheme 9. Intramolecular cyclization of OJ-aminoboronic esters. Table 1. lIB NMR Shifts ofOJ-Aminoboronic Esters 20a-i Compound n R1 R2 R3 R' 6 lIB (ppm) 20a 0 H H H H 27.5 20b 1 H H H H 19.1 20c 1 ipr H H H 32.3 20d 1 H Me H H 11.4 20e 1 H Me H Hex 18.4 20r 2 H H H H 33.8 20g 2 H H H Ph 33.8 20b 2 H H H Hex 33.8 20i 3 H H H H 34.0 In subsequent work, Vaultier and co-workers reported that the reaction of aminoborane 21 with benzyl azide and HCl formed reduced 1,2-azaborine 22 which reacted further with HCI, producing dichloroborane 23 (Scheme 10).23 Unfortunately, characterization of23 was limited to liB NMR spectroscopy (6 7.8 ppm). Paetzold and co-workers used a similar ring-expansion strategy to generate bicyclic aminoborane 24 (Scheme 11), which could be further reacted with Me3SiN3 to give azide-substituted amino-borane 25.24 8 Me~ + MeaSiNa 2 ~B-CI _MeaSiCI .. 9 CSNEt, Ph~~~N,' [ C(~] Hel. c~:n 21 22 23 Scheme 10. Reaction of aminoborane 21 with benzyl azide and HCI. Me Me Me-(wO + Me,SiN,. Me-(~-OB -MeaSiCI B 'CI 'Na 24 25 Scheme 11. Formation ofB-Cl aminoborane 24 and azide-substituted aminoborane 25. The Ashe group achieved a breakthrough in the mild synthesis of monocyclic 1,2-azaborines in 2000. Whereas previous syntheses relied on desulfurization or dehydrogenation at extreme temperatures as discussed above, Ashe and co-workers used a ring-closing metathesis/oxidation protocol for the efficient formation of 1,2-azaborines (Scheme 12).15 Transmetallation of allyltributyltin with BCh generated allylboron dichloride 26 in situ. Condensation with allylethylamine produced bisallyl aminoborane 27. The addition of PhLi led to the displacement of chloride from the labile B-CI bond to give B-Ph aminoborane 28 in good yield. Ring-closing metathesis with Grubbs' 1st Generation catalyst formed I ,2-azaborine precursor 29 featuring an olefin at the 4- position. The oxidation to 1,2-azaborine 30 was accomplished in good yield using 2,3- dichloro-5,6-dicyano-I,4-benzoquinone (DDQ) at 35°C. 10 • ~N~Et HBCIS • [~BCI2] 26 ~N~Et I ~B'CI 27!PhLi (~~Et • DDQ C~~Et • (CYsPMPhCH)RuCI2 ~~~Et~ B'Ph B'Ph ~B'Ph ~ ~ ~ Scheme 12. Synthesis of 1,2-azaborine 30 via ring-closing metathesis. A year later, Ashe et al. explored a ring-expansion route to 1,2-azaborines from the 1,2-azaborolide heterocycle, which is formally isoelectronic with the ubiquitous cyclopentadienide (Cp) anion. Ring-closing metathesis from B-vinyl aminoboranes 31a- c provided heterocycles 32a-c (Scheme 13), which were deprotonated to give 1,2- azaborolides 33a_c.26 The reaction of 33a-c with CH2Ch and lithium diisopropylamide (LDA) (the Katz reaction) gave 1,2-azaborines 34a-c. A deuterium labeling study suggested that the initial attack of chlorocarbene occurs at the C3 position of 33c. Carbene insertion into the B-C bond leads to a 3-deuterio isomer of 34c via carbene 35. Deuterium incorporation at this position rules out initial substitution at C5. ~N'R1 I ~B'R2 31 a R1 =Me, R2 =Ph b R1 = Et, R2 = Ph C R1 ='Bu, R2 =Me CH2CI2, LOA. (~~R1 ~ B'R 2 34 r-~,'BU [:CDCI]. r f'~,'BU l__~ ~N"Bu ~~'Me -[CIG] l )..-B'Me J · ly~'Me 33c Df D 35 34c Scheme 13. Ring-expansion route to 1,2-azaborines 34a-c and deuterium labeling. 11 The Ashe group has extensively studied the coordination chemistry of 1,2- azaborine with transition metals. The reaction of (MeCN)3Cr(CO)3 with 34a leads to the formation of piano-stool structure 36 (Scheme 14).26 The solid-state structure of36 revealed that the 1,2-azaborine ligand binds in an YJ6 fashion to chromium. The 1,2- azaborine ring is planar, and the phenyl ring is twisted out the 1,2-azaborine plane. The B-N bond length is 1.466(6) A, which is slightly longer than a typical unconjugated aminoborane B-N bond (1.41 A),27 indicating some delocalization ofthe B-N:Jt- electrons. The structural features of 36 and 37 are typical for other arene piano-stool complexes.28 34a (MeCNhCr(COh .. wMe(G);S-Ph I ......Cr··,CO OC ~CO 36 34c tsuN'(G);S-Me I .....Mo·,CO OC ~CO 37 Scheme 14. Formation of'Y]6 complexes of 1,2-azaborines with group 6 transition metals. Ashe and co-workers synthesized 1,2-azaborine 38 via the ring-expansion route discussed above.29 The addition of B14NF to TMS-protected 38 provided an alternate route to N-H 1,2-azaborine 5 (Scheme 15), which could be reversibly deprotonated at the nitrogen position to give 39. 1,2-Azaborine 39 was found to be a good ligand for ruthenium (40 in Scheme 15). Protonation of sandwich complex 40 with AcOH gave salt 41. Whereas the pKa of heterocycle 5 was found to be comparable to 12 pentamethylcyclopentadiene (~26), the pKa of 41 was determined to be 9.2 via potentiometric titration. base. eNG acid I • ~ B.'Ph 39![Cp*RuCIl4 (±)H N' N !':. · tr(Co)s I Cr(CO)s 45 44 Scheme 16. Switchable haptotropic migrations of the 2-phenyl-I,2-azaborine ligand. Table 2. Selected Bond Distances (A) for 42 and 43. 42 43 BI-Nl NI-Cl CI-C2 C2-C3 C3-C4 C4-Bl 1.450(2) 1.430(5) 1.383(2) 1.368(5) 1.389(2) 1.353(6) 1.421(2) 1.413(7) 1.395(2) 1.370(6) 1.524(2) 1.500(5) The solid-state structure of 43 was determined, which was the first crystallographic characterization of a 1,2-azaborine that was not directly bound to a metal. The 1,2-azaborine bond distances for 43 are presented in Table 2 and are 14 consistent with bond delocalization throughout the planar 1,2-azaborine ring. The formal single bonds (NI-Cl, C2-C3, and BI-C4) are shortened and the formal double bonds (B I-Nl, CI-C2, and C3-C4) are lengthened relative to typical B-N and C=C bonds. The crystal structure of 42 was also obtained. The 1,2-azaborine ring distances for 42 (Table 2) are lengthened relative to 43. This is consistent with the donation of Jt- electron density from the 1,2-azaborine ring of 42 into chromium as well as backdonation of chromium's d-electrons into the anti-bonding orbitals of the ring system. The coordination chemistry of 1,2-azaborine is not only tunable via protonation/deprotonation, but is also dependent on the choice of metal. The reaction of anionic 1,2-azaborine 39 with Cp2ZrCh led to the formation of complex 44 (Scheme 17) in which the 1,2-azaborine ligand was a-bonded to zirconium.31 ( B 1 .... Ph ( Ne CP2ZrCI2 I ----='-------- ~ N:9 B"' Ph (N:zrcP2 ~ S"'Ph 44 Scheme 17. Formation ofr{zirconium complex 44 (not balanced). The Ashe group also explored the ligand properties of deprotonated BN-styrene 45 (Scheme 18),32 which was synthesized via the ring expansion route discussed above. The reaction of 45 with 1 equivalent of [Cp*RuCI]4 gave complex 46 in which BN- styrene was bound to ruthenium in an '11 6 fashion. However, when 2 equivalents of [Cp*RuCI]4 were added, diruthenium complex 47 was formed. In complex 47, '116 15 binding occurred between a ruthenium atom and the 1,2-azaborine ring, while the second ruthenium bound 11 1 to the 1,2-azaborine nitrogen. An additional112 interaction between ruthenium and the B-vinyl group was observed. jMel Me Me I I ~,MeO::JMe ..I ~ ~ \Cr(COh 112 111 Scheme 39. Haptotropic migration in B-methyl 1,2-azaboronaphthalene. Alternative syntheses of 1,2- and 9,1 O-substituted derivatives have recently been reported. In 2006, Ashe and co-workers used a ring-expansion from bridehead- substituted BN-indene 113 to generate 9,lO-azabornaphthalene 92 (via 114 in Scheme 40);72 in analogy to the ring-expansion of 1,2-azaborolides discussed in section 1.2.1. The chemistry ofBN-indenes will be discussed below. Murakami and co-workers prepared anilinium borate 115 and found that Pd-catalyzed ring-closure gave bicycle 116 41 in good yield (Scheme 41).73 The B-N bond in 116 is a dative a-interaction and thus 116 is not formally isoelectronic with naphthalene. In a crossover experiment, Murakami and co-workers determined that aryl migration to the 3-position occurs intramoJecularly from the borate. 113 (~)~ B 0 92 Scheme 40. Ring-expansion ofBN-indene to BN-naphthalene 92. 2.5 mol% Pd2dba3-CHC13 Me2 6 mol% P(o-tolb • NN'~Ph2 ~Ph H 116 Scheme 41. Pd-catalyzed ring-closure to bicycle 116. Additional [4.4.0] bicycles containing the B-N bond pair have been prepared. Butler and co-workers prepared bridgehead-substituted BN-decalin derivatives via Dewar's established route. 74 The first example of2,I-substitution in [4.4.0] BN- heterocycles was achieved by Catlin and Snyder in 1968 via the hydrolysis of nitrile 117 to bicycle 118 (Scheme 42).75 Reduction with LiAIH4 produced 2, I-substituted 119. Alternatively, the direct fonnation of 119 resulted from the reduction of 117 with LiA1H4.76 Koster et al. synthesized derivatives of 119 a year later through the arylation f . b 77o ammo oranes at extreme temperatures. mH2BHS 121 42 119 Scheme 42. 2, I-Substituted BN-heterocycles synthesized from ortho-boronic acid 117. Vedejs and co-workers described the synthesis of a reduced analog of 119, parent BN-decalin 120 (Scheme 43).78 The hydroboration of amine-borane 121 to 2,1- azabordecalin 120 occurred readily when catalytic amounts of h were added. No attempts to oxidize 119 or 120 to the unexplored 2,1-azabomaphthalene were described in either of these reports. 10 mol% 12 rY'l • Vl-B.. ~IH2 H2 120 Scheme 43. Hydroboration of 121 to 2, I-azabordecalin 120 catalyzed by 12• Midland et al. have explored the use of chiral amine-boranes as enantioselective reducing agents.79 The formation of terpenic ring-fused heterocycle 123 was accomplished via the condensation-hydroboration of aminoterpene 122 (Scheme 44). The coordination of BH) to the fu'11ine of enantiopure 123 formed complex 124, which was found to provide good enantioselectivity in the reduction of acetophenone to the 43 corresponding alcohol. The stereochemistry of the major enantiomer in these reductions was not reported. Et3NBH3 • Me-+1--h BH3-THF. Me~'BH3~B"N'pr ~Bj 'Pr H I H I H H 123 124 Scheme 44. Synthesis ofterpenoid BN-heterocycle 124 for the stereoselective reduction of ketones. Roberts and co-workers examined the use of chiral amine-boryl radicals for the kinetic resolution of esters via hydrogen-atom abstraction (equations 1 and 2).80-81 Hydrogen abstraction from electron-deficient C-H bonds, such as the alpha C-H group in carbonyl compounds, occurs slowly using an electrophilic tert-butoxy radical. The addition of amine-borane complexes has been shown to catalyze this transformation through the formation of a nucleophilic boryl radical which readily abstracts the electrophilic hydrogen atom. tBuO' + amine-BH2R -+ tBuOH + amine-BHR Bicycle 125 was found to be an effective catalyst for the selective hydrogen abstraction from the (R)-enantiomer of racemic lactone 126, and was relatively unreactive toward the (S)-enantiomer (Scheme 45). The enriched (S)-lactone 126 was recollected via column chromatography in high enantiomeric excess. (1) (2) 44 0yo,> Eto/--fMe Me (:)-126 125 tBuO-OtBu hv -74°C °Y°,> EtO~Me Me (S)-126 Me H Me~Et2lG+-Bj H H2 125 Scheme 45. Kinetic resolution of racemic lactone 126 with amine-borane 125. Hancock and co-workers reported the photo-induced cyclization ofB-vinyl aminoborane derivatives (Scheme 46).82 Irradiation of aminoborane 127 led to the formation of a C-C bond in the ortho-position of the aniline ring to give 128. A mechanistic study of this cyclization revealed that the ortho-hydrogen underwent an intramolecular 1,5-shift.83 127 hv Me Et OCAN'B~Et• ~ I HEt Et 128 Scheme 46. Photocyclization ofvinylborane 127. The only synthesis of a 2,3-substituted [4.4.0] BN-heterocycle was reported by Kafka et a1. 84 The condensation-hydroboration of benzyl amine 129 with Et3N-BH31ed to a mixture of non-aromatic [4.4.0] 2,3-aminoborane 130 and [4.5.0] heterocycle 131 (Sche1ne 47). Though the synthesis of2,3-azabofonaphthalene utilizing this route seems feasible, there have been no reports of its attempted synthesis. 45 Me ~ _Et_3t\_IB_H_3_. ~~H2 + ~BH2~NMe2 ~NMe2 ~JMe2 129 130 131 Scheme 47. Synthesis of2,3-substituted BN-heterocycle 130. Several theoretical studies ofBN-naphthalene have been reported.37,38,41,47,85-89 Michl et al. calculated the electronic features of the isomers ofBN-naphthalene, which are summarized in Table 9.41 The predicted UV-Vis absorption energies ofBN- naphthalene varied for each isomer, with 9,1-azaboronaphthalene having the largest bathochromic shift at 366 nm. The BN-naphthalene isomers that have been synthesized, i.e. the 1,2- and 9,lO-isomers, were calculated to have significantly highest energy absorptions. The experimentally determined absorption of 1,2-azaboronaphthalene 76 at 318 nm was in good agreement with these calculations. Similarly, the calculated absorption maximum for 9,lO-azaboronaphthalene 92 was identical to the experimental value (Amax = 301 nm).85 It is of note that all BN-naphthalene derivatives were calculated to have a red-shifted absorption relative to unsubstituted naphthalene. The isomers with the greatest :rt-electron density at boron were 1,9- and 9-10- azaboronaphthalene, both of which have the boron atom in a bridgehead position. This may in part explain the hydrolytic stability and upfield lIB NMR chemical shift of9,10- azabomaphthalene 92. Conversely, the B-N :rt-bond order was calculated to be greatest in the 1,2- and 2,l-isomers, indicating more double-bond character in the B-N bond pair for these isomers. The electronic features predicted by Michl et al. corroborated earlier work by Hammond.86 46 Table 9. Electronic Features ofBN-Naphthalene Isomers [N,B] 1st Singlet Ioniz. Pot. Jt-electron Subst. Transition (eV) density at Position (run) boron (e) Jt-electron density at nitrogen (e-) B-N Jt-bond order None 299 8.11 [1,2] 309 8.41 [2,1] 304 7.79 [2,3] 350 7.57 [9,10] 301 8.27 [1,9] 346 7.92 ~9,1] 366 7.57 0.425 0.412 0.498 0.558 0.554 0.484 1.528 1.516 1.423 1.359 1.422 1.366 0.587 0.583 0.525 0.476 0.484 0.475 Scheiner and co-workers calculated the relative energies of the isomers ofBN- naphthalene (Figure 13).87 The most stable isomer was 2,1-azabomaphthalene, followed by the 1,9-isomer. The least stable isomer was predicted to be the 9,I-isomer. The only calculations of a synthetically available BN-naphthalene were on 9,10- azabomaphthalene 92, which was predicted to have an intermediate stability with respect to the other isomers. Unfortunately, calculations on the other accessible isomer, 1,2- azabomaphthalene 76, were not performed. increasing stability Figure 13. Relative stabilities ofBN-naphthalene isomers (N- and B-bonded H atoms omitted where appropriate). 1.2.4. Additional C4BN-Containing Bicyclic Motifs Paetzold and co-workers extended their work (see section 1.2.3) on iminoboranes to include cyclizations with cyclopentadiene.90-91 The reaction of aminoborane 132a with cyclopentadiene led to the formation of a BN-substituted derivative of norbomadiene (133a in Scheme 48).90 It was unclear whether this occurred via the 47 formation of an intermediate iminoborane 134a, however Gilbert has performed calculations that suggest iminoborane 134a is a precursor in the cyclization.92 The scope of this reaction was extended to include an amino group to provide BN-norbomadiene 133b from aminoborane 132b.91 R IBu 'B=N' ------ [R-B=N-IBU] cl' SiMea - MeaSiCI 134a-b 132a-b o LZtN}BU'I .,B \ R 133a-b a R = C6Fs b R = N(SiMea)IBu Scheme 48. Cyclization to BN-norbomadiene 133. Ashe and co-workers more recently synthesized an analog of indene substituted at the bridgehead position by the B-N bond pair (Scheme 49).93 The formation of aminoborane 135 was accomplished in an analogous method to that used for the creation of the monocyclic derivatives discussed above. Substitution of vinyl Grignard provided 136, which was reacted with Grubbs' 1sl generation catalyst to form both the 5- and 6- membered rings of 137. Oxidation with DDQ provided BN-indene 138. The use ofBN- indenyl as a ligand in transition-metal complexes was next examined. Deprotonation of the 5-membered ring in 138 gave anionic BN-indenyll39 which was reacted with Cp*ZrCh to provide complex 140. The preferred binding site for zirconium was 11 5- coordination to the Cp-like ring ofBN-indenyl, which was confirmed by X-ray crystallography. The heterocycle was completely planar, but the bridgehead atoms of the 5-membered ring were slightly distorted away from zirconium. 48 ~MgSr • ~~~ (CY3Ph(PhCH)RUCI2 • (N S' r ~S~ J 136 137 138 jDDQ (~) 139 <§~? .. Cp*ZrCI3 I ZrCI2Cp* 140 Scheme 49. Synthesis ofBN-indene 138 and coordination chemistry of the BN-indenylligand. The haptotropic migration of the indenylligand was also explored by Ashe and co-workers.94 Complexation of neutral BN-indene 138 with chromium led to the preferential formation ofr{complex 141 (Scheme 50). Deprotonation at low temperature gave complex 142 as evidenced by the disappearance of the allylic signals in the IH NMR spectrum. Whereas significant heating was required to force the haptotropic shift in B-phenyl 1,2-azaborines, simply warming the solution of 142 to room temperature caused a shift in chromium complexation to the anionic ring (143 in Scheme 50). Intermediate 143 was trapped with Me3SnCI as complex 144, which was analyzed by X-ray crystallography. The crystallographic parameters of 115-coordinated indenyl complexes 140 and 142 matched the geometric parameters calculated for similar complexes.95 49 C~§J I Cr(COb 141 K~~~~~3h • ~~§J I Cr(COb 142 J-60°C --+ 25°C @~:) Me3SnCI @~:) I • I Me3sn.....Cr(COb e Cr(COb 144 143 Scheme 50. Haptotropic migration of the BN-indenylligand. (MeCNbCr(COb 138 Wrackmeyer et al. have published numerous reports on a closely related [4.3.0] bicyclic system containing a B-N bond pair.96-98 The substitution of boron and nitrogen at the 7- and 8-positions, respectively, was achieved via the coordination of an allyl borane to a pendant N-heteroaromatic pyrrole (Scheme 51).96 Alkoxy-substituted bicycle 145 was synthesized readily from dilithiate pyrrole 146. Compound 146 was reacted with B(OEt)3, providing 4-coordinate compound 147. Heterocycle 147 was reacted with Me3SiCI, which abstracted an ethoxy group from the 4-coordinate boron to give 145. Alternatively, alkyl-substituted derivatives were prepared via transmetallation from bicyclic stannane 149. Wrackmeyer et al. expanded the synthetic scope of the bicyclic ring formation by reacting various hydroborating reagents with 2-allylpyrrole,97 and the reactivity of these derivatives was explored.98 Though 145, 149, and subsequent derivatives can be considered tautomers ofBN-indene (Figure 14), no attempt to tautomerize 150 to 1,2-azaborine-containing 151 was reported. This could be due to the large aromatic stabilization of the pyrrole unit in tautomer 150 relative to the 1,2- azaborine unit oftautomer 151. 50 EtO OEt OEt ~ a:JUCB IB(OEtb Me3SiCI 0:).. ...--::: ~ - Me3SiOEt .--::: ~ 'I' - LiCI 145Li 147 146 Me Me Et '. , 1/2 (Et2BHh ICO hexane/BEt3 0:)...--::: ~ .--::: ~ 148 149 Scheme 51. Formation of7,8-substituted BN-indene analogs. H+ H(Q;r,BH (OBf ) ....- .. " N, I ~ ~ " ,'- 150 151 Figure 14. Tautomerism in 7,8-substituted I3N-indene. Matteson et aJ. achieved the synthesis of the 8,7-azaborquinazoline analog presented in Figure 15. The authors' motivation was directed toward biomedical applications, though compound 152 was detcmlined to be inactive in standard leukemia screcning.99 NH 2Nn,-,::B(OHh 1:--,. I B '-::::N N' 'OH I H 152 Figure 15. BN-Quinazoline 152. 1.2.5. Tricyclic C4BN-Containing Motifs Tricyclic analogs of phenanthrene were among the first B-N aromatics synthesized. Dewar pioneered the synthesis of 9, lO-azaborphenanthrene derivatives 51 over 50 years ago,100 from which numerous studies on the properties and reactivity of BN-phenanthrene have since emerged. The early achievements in the study ofBN- phenanthrene were due to its relatively simple preparation. The reaction of 2- phenylaniline with BCh and AICh gave 9,1O-azaborphenanthrene (153 in Scheme 52), presumably through the Friedel-Crafts cyclization of intermediate 154. The substitution of various nucleophiles at the reactive B-CI unit of 153 allowed for the synthesis of several BN-phenanthrene derivatives. Hydrolysis of 153 gave hydroxy-substituted 154 (Scheme 52), while reaction with alkyl and aryl Grignard reagents produced the corresponding boron-substituted derivatives 155 and 156, respectively. Addition of LiAIH4 to 153 readily produced the parent BN-phenanthrene 157. The isoelectronic relationship between BN-phenanthrene 157 and its carbon analog was explored via UV- Vis spectroscopy. The spectrum of 157 resembled very closely that of phenanthrene in the position ofthe main absorption bands. However, an increase in the intensity of the a-band was observed, an effect that was attributed to removing the molecular orbital degeneracy in the BN-substituted heterocycle. 6 5 9f\lH2 BCls f\lHBCI2 AICls f\lH .. • I 4 BR 10 s 154 2 153 R = CI 154 R = OH 155 R = Me 156 R = Ph 157 R = H Scheme 52. Preparation of9,lO-azaborphenanthrene 153 and boron-substituted derivatives. 52 The reactivity ofBN-phenanthrene toward EAS was successfully demonstrated, and like 1,2-azabornaphthalene and 1,2-azaborine, was found to be highly regioselective. 101 The chlorination of 155 with Cb provided 8-chloro derivative 156 (Figure 16) as the major product, which was confirmed by an independent synthesis of 156. A second chlorinated product was also observed in very small quantities and was likely 6-chloro BN-phenanthrene 157 based on a comparison of absorption spectra. The observed substitution pattern was consistent with the predicted products; the ortho- and para-directing nitrogen atom at the 9-position resulted in substitution at the 8- (ortho-) and 6- (para-) positions. Conversely, the deactivating boron substituent at the 10- position was expected to act as a meta-directing group, leading to 2-chloro derivative 158. Howevcr, product 158 was not detected in the chlorination reaction. The nitration of 155 with nitric acid led to the formation of thc 8-nitro 159 and 6-nitro 160 products in a 1 to 2 ratio, respectively. Isomer 161 was not observed. It was also determined that chlorination and bromination at both the 6- and 8-positions readily occurred at room temperature if more than 1 equivalent of halogen was added to the reaction. 102 Similarly, mono- and di-acetylated products were obtained from the Friedel-Crafts acylation of 155, with the first acylation likely taking place at the 6-position.103 NH I BMe E NH I BMe 160 E = N02 I\JH I BMe E E 159 E = N02 158 E =CI 161 E = N02 Figure 16. Chlorination and nitration products of BN-phenanthrcnc. 53 Dewar et al. determined that the nitrogen position of 9,1 O-azaborphenanthrene could be deprotonated with butyl lithium to give N-lithio derivatives. 104 These anionic nucleophiles were then reacted with electrophiles to afford additional substitution at nitrogen. It was realized that tuning the electronics of the nitrogen substituent could have an effect on the electronics of the heterocycle as a whole. If the aromatic stability ofBN-phenanthrene was in part due to the participation of the nitrogen lone-pair in the aromatic Jt-system, then the stability would be reduced by functional groups that interrupt the Jt-donation. This was examined via the installation of an acyl group at nitrogen, which was expected to reduce the ability of nitrogen to act as a Jt-donor. 105 The reaction ofN-lithio BN-phenanthrene 162 with ethyl chloroformate gave carbamate 163 (Scheme 53). While compound 163 was reasonably stable toward hydrolysis, it rapidly oxidized when exposed to air, in sharp contrast to other derivatives that were quite air-stable. The degradation products of this oxidation showed evidence of reactivity at boron and cleavage of the B-N bond. Thus, it is probable that the aromatic stability of 163, and in particular the B-N Jt-bond, was significantly disrupted by the N- acyl substituent. NLi I SMe o CI)lOEt o N)(OEt I SMe 54 162 163 .. 0- +AN R I SR Scheme 53. Installation of a n-accepting group at the nitrogen ofBN-phenanthrene 163. Subsequent studies have focused on intermolecular interactions of several derivatives ofBN-phenanthrene. For example, in an attempted preparation of parent 9,1 O-dihydro-9,1O-azaborphenanthrene 157 from 2-phenyl aniline and triethylamine- borane, Koster et al. observed the evolution of hydrogen and isolated the trimerized product 164 containing a borazine core (Figure 17).106 164 Figure 17. Trimerization ofBN-phenanthrene with a borazine core. Philp and co-workers recognized that the adiacent boron and nitrm!en atoms in - - ... ....... 154 could potentially act as neighboring hydrogen-bond donor and acceptor groups, leading to intermolecular interactions like those seen in dimeric complexes of benzoic 55 acid. In the solid-state structure of 154, the oxygen atom bound to boron forms a hydrogen bond with the N-H group of an adjacent heterocycle to form a dimeric structure containing two hydrogen-bonds (Figure 18).107-108 Philp and co-workers also achieved the efficient dehydration of 154 to its corresponding B-O-B ether. 107 H I 0- 0+ "o.... s WW I I WN s....o--' 0+ 0- I H [15412 Figure 18. Hydrogen-bonding of 154 in the solid-state. Several additional isomers of BN-phenanthrene have been reported. Dewar and co-workers achieved the ring-closure of 1,2-azabornaphthalene 165 to give bridgehead- substituted tricycle 166 (Scheme 54).109 Oxidation to BN-phenanthrene 167 was performed with PdlC at 300°C. The UV-Vis spectrum of 167 closely resembled that of the 9,10-isomer. Piers and co-workers recently described the synthesis and optoelectronic properties of another BN-phenanthrene isomer, 168 in Scheme 55. l10 The reaction of 2-ethylnylpyridine with l-chloro-2-trimethylsilyl-boracyclohexa-2,5-diene led to the formation of alkyne-substituted BN-biphenyll69 via the elimination of Me3SiCl. Heterocycle 169 spontaneously ring-closed to afford 4a-aza-4b- boraphenanthrene 168 containing the internalized B-N bond pair. 56 Pd/C • 165 166 167 Scheme 54. Cyclization to bridgehead-substituted BN-phenanthrene 167. .. oB H ifl #:-- I~•- MeaSiCI UB SiMea I CI 1~ 1~ Scheme 55. Fonnation ofBN-phenanthrene 168 with an internalized BN bond pair. Piers and co-workers explored the electronic properties of internally substituted 169 in relation to the previously known isomer 157 with the B-N bond pair at the periphery. It was determined that the position ofB-N substitution played a major role in the photophysical properties ofBN-phenanthrene isomers, which are summarized in Table 10. The absorption and emission spectra of 157 indicated that the B-N bond pair acted mainly as a bridging group for a fluorogenic biphenyl moiety. On the other hand, the internalized B-N bond pair of 169 was found to be intimately involved in absorption- emission, leading to a drastic change in the observed spectra. Fluorescence in 169 was found to be more efficient than phenanthrene and the "-max was red-shifted into the visible spectrum. The observation of blue fluorescence in 169 was an exciting result and opens the way to BN-substituted aromatics with improved properties for materials 57 applications. Piers and co-workers found that 169 was exceptionally stable to moisture and they demonstrated through NICS calculations that all three rings ofBN- phenanthrene 169 have significant aromatic character. - I7' ~ SR ~~ I h- 208 R = Cl 209 R = Me 210 R = H Figure 26. Phenanthrene derivatives containing the 1,3-diaza-2,4-diborine unit. Frange and co-workers described the coordination chemistry ofbenzo-fused 1,3- diaza-2,4-diborines with Group 6 transition-metals. The reaction ofBN-naphthalene 211 with Cr(CO)6 and W(CO)6 led to the formation of piano-stool complexes 212 and 213, respectively (Scheme 66).151-152 The coordination of the metal to the fused benzene ring was seen in both cases, and no evidence of coordination to the 1,2-diaza-2,4- diborine or pendant tolyl rings was observed. Upfield chemical shifts were observed in the I H and l3C NMR signals for the benzo substituent, consistent with Jt-coordination of the metal at this ring. The sterically crowded environment around the biaryl bond results in restricted rotation of the penda...1J.t tolyl ring. .LA~S a result, a one---to-one ratio of diastereomers is formed by coordination of the metal to either face of the benzo ring. 71 The identities of the diastereomers were determined by 2D NMR and X-ray crystallography,I53 M(CO)6 .. 212M=Cr 213 M = W Scheme 66. Atropisomerism in piano-stool complexes ofBN-naphthalene 211. 1.3.3. 1,4-Diaza-2,3-diborines Though the number of I ,4-diaza-2,3-diborine derivatives is limited, there have been significant efforts toward the synthesis of this interesting benzene analog which features a B-B bond. To date there has been no report on the synthesis of a monocyclic, aromatic 1,4-diaza-2,3-diborine. Noth has reported the preparation of naphthalene, phenanthrene, and anthracene derivatives 214-216, respectively (Figure 27), via the reaction of an ortho-diaminoarene and a diboradiamide. 154 The complexation of a B- butyl analog of214 with Cr(CO)3 took place at the benzo ring as evidenced by the substantial upfield shifts in the IH NMR signals of the homoaromatic ring protons. 155 Cowley, Marder, Norman and co-workers prepared an oxo-bridged dimer of 1,4-diaza- 2,3-diborine (217 in Figure 28) and obtained an X-ray crystal structure. 156 The structure is completely co-planar and the bond lengths are consistent with a delocalized Jt-system. In fact, the B-B bond is quite short (1.683(3) A) compared to that of another boron oxide discussed in the report (1.732(3) A). It was the first solid-state structure containing a B- B bond as part of an aromatic ring. 72 214 215 216 Figure 27. 1,4-Diaza-2,3-diborine analogs ofpolycyclic aromatic hydrocarbons. ISU ISU I I ( N... S"..O.... S .... N]I I I IN~S ....O~S'N I I ISU ISU 217 Figure 28. 1,4-Diaza-2,3-diborine 217 containing the first structurally characterized "aromatic" B-B bond. The inherent difficulty in the synthesis of 1,4-diaza-2,3-diborine is in part due to the preferred formation of a bicyclic structure over the ring-fused isomer (Figure 29). Shore and co-workers found that when nitrogen was replaced with oxygen or sulfur, the ring-fused structure was preferred. 157 In contrast, the reaction of ethylenediamines with diboranes leads to the bicyclic structure almost exclusively. Norman, Russell and co- workers determined that the bicyclic isomer was the thermodynamic product of the reaction of B2(NMe2)4 and ortho-diaminobenzene.158 However, the intermediate formation of a ring-fused BN-tetracene was demonstrated and both compounds were isolated and analyzed by X-ray crystallography. The B-B bond in the ring-fused isomer was shortened relative to the bicyclic B-B bond, consistent with the data for 217. ,........N. .N-.,l ,S-S~ J N N ring-fused bicyclic Figure 29. Ring-fused and bicyclic isomers oftetraaminodiborane (N-bonded H atoms omitted). 73 The conversion of the ring-fused structure to the bicyclic motif was demonstrated in the presence of additional ortho-diaminobenzene. Marder, Norman, Orpen and co- workers have also had some success in generating the 1,4-diaza-2,3-diborine motif from 2,2' -dipyridine and 1,1O-phenanthroline. 159 1.3.4. 2,3-Diaza-1,4-diborines Siebert and co-workers published the first example of a monocyclic diazadiborine in 1976,160 the preparation of which was detailed a few years later. 161 The reaction ofthiaborole 218 with hydrazines provided 2,3-diaza-1,4-diborine 219 and 220 with the loss ofHzS (Scheme 67). Crystallization of219 at low temperature permitted the collection of single-crystal X-ray diffraction data, which indicated a planar ring structure. Complexation of 2,3-diaza-1 ,4-diborines 219 and 220 to Cr(CO)3 gave piano- stool complexes 221 and 222, respectively, which were purified by sublimation. The rt binding of 221 to chromium was confirmed by X-ray crystallography and NMR spectroscopy. A similar route to benzannulated analogs (isoelectronic with naphthalene) was estabilished,16Z-163 and in this case it was found that metal coordination with chromium, molybdenum, and tungsten occurred selectively at the benzo-fused carbocycle, similar to the 1,3-diaza-2,4-diborine isomer discussed in section 1.3.2. + 218 Me EtXBI :S Et ~ Me ¥e R'N_W R Et)S'WR (MeCNhCr(COh Me-S~~ 'S-Me • I I • - H2S Et S"N'R Et I Et Me Cr(COh 219 R = H 221 R = H 220 R = Me 222 R = Me Scheme 67. Synthesis of2,3-diaza-I,4-diborines 219-220 and respective Cr(CO)3 complexes 221-222. 74 An alternate route to the 2,3-diaza-l ,4-diborine motif was explored by Paetzold and co-workers. 164 The highly reactive head-to-head dimer 223 was reported to undergo a cycloaddition reaction with 3-hexyne to furnish the highly-substituted 2,3-diaza-l,4- diborine 224 (Scheme 68). The same heterocyclic motif was obtained when 2 equivalents of tert-butylisocyanide were added to 223, providing imine-substituted 225. .. Et----=~-Et 223 tsu tsu I I NI~S ~~Et • 2 tSuCN N;"- S N'Et I Itsu tSu 225 Scheme 68. Cycloaddition of 223 to 2,3-diaza-l,4-borine derivatives 224 and 225. Analogs of polycyclic aromatic hydrocarbons containing a 2,3-diaza-l ,4-diborine core have recently been explored. 2,2' -Bisborabenzene, the Lewis acidic counterpart to 2,2' -bipyridine, was synthesized via the reaction of precursor 226 with neutral Lewis bases (Scheme 69).165 When pyridazine and benzo[c]cinnoline were used as the base, the formation ofBN-triphenylene 227 and dibenzo[g,p]chrysene 228 occurred. Both of these BN-aromatics contained the 2,3-diaza-l ,4-diborine core and displayed absorption spectra consistent with a highly conjugated Jt-system. While the structure ofBN- triphenylene 227 was presumably planar, the steric repulsion ofthe 3,3'-hydrogen atoms in 228 forced the molecule to twist out of planarity. Electrochemical measurements showed that 228 was more easily reduced than 227, indicating a lesser degree of aromatic stabilization in the non-planar 228, These data were confirmed via X-ray crystallography where it was shown that BN-triphenylene 227 was completely planar whereas 228 was twisted out of plane.166 The fluorescence of 227 was in sharp contrast 75 to the non-fluorescent nature of228, which was again ascribed to the structure of228 in which molecular twisting disrupts conjugation in the scaffold. The absorption and emission maxima of227 were both red-shifted by over 100 nm relative to triphenylene, suggesting as in previously described BN-heterocycles that substitution ofthe B-N bond pair has the potential to impart unique optoelectronic properties. iPr~CI\SiMe3 - H B ~ ~ B H - \ . Ma3Si CI 'Pr 226 N=N V - Ma3SiCI 227 - Ma3SiCI 226 iPwr \ I 't-H N=N H <><> 228 Scheme 69. Polycyclic aromatic hydrocarbons substituted with a 2,3-diaza-1 ,4-diborine core. 1.3.5. 1,3-Diaza-4,6-diborines There have only been two reports to date on the preparation of an aromatic 1,3- diaza-4,6-diborine heterocycle, both by Roesler and co-workers. 167-168 The reaction of an aryl-substituted trimethylsilyl formamidinate with a bis(chloroboryl)ethane formed the corresponding zwitterionic heterocycles 229-231 (Scheme 70). Deprotonation at the 5-position provided the 1,3-diaza-4,6-diborines 232-234, all of which were structurally characterized by X-ray crystallography. The heterocycles were planar in all cases and 76 the intra-ring bond lengths indicated significant delocalization of the n-electron density over the B-C-B and N-C-N fragments. However, the long intra-ring B-N distances (- 1.50 A) suggested that the bonding in the 1,3-diaza-4,6-diborine heterocycle was more accurately described by two allyl fragments which formed the zwitterionic structure illustrated in Scheme 70 rather than a fully delocalized aromatic system. This bonding depiction was supported by calculations on a related BN-heterocycle. 169 Heterocycle 232 was deprotonated at the 2-position with a lithium base to generate a metal- coordinated phenylide-like structure. 167 Alternatively, deprotonation of233 or 234 with a potassium base in the presence of 18-crown-6 provided the corresponding free carbanions, which were characterized by X-ray crystallography. 168 H Ar'NAW Ar + I SiMe3 Ar = 2,6Jpr2C6H3 H H Me3SiOTf Ar'N~~,Ar KHMDS Ar'N~wAr • I e' ---.... I IR~BXB,-OTf R~BtB,R H MeR Me 229 R = Me 232 R = Me 230 R = Ph 233 R = Ph 231 R = NMe2 234 R = NMe2 Scheme 70. Synthesis of 1,3-diaza-4,6-diborines 232-234. 1.3.6. Non-aromatic Analogs of1,3-Diaza-2,5-diborine and 1,4-Diaza-2,5-diborine The 1,3- and 1,4-diaza-2,5-diborine isomers were predicted to be thermodynamically stable,141 yet no route to these aromatic motifs has been reported. There have been numerous reports on the preparation of related compounds featuring 4- coordinate boron and carbon atoms. The first example of a fully saturated 1,4-diaza-2,5-diborine was described by Miller and co-workers in 1964.170 The reaction ofH2B(N(CH3)3)2Cl with sodium 77 hydride resulted in the formation 235, which was an isoelectronic analog of 1,1,4,4- tetramethylcyclohexane (Figure 30). Over the next three decades, several studies d f M'll 171-179 d th 180-181 d' h .. d'"emerge rom 1 er an 0 ers regar mg t e reactIVIty an mtnnsIc characteristics of this cyclohexane mimic. Structurally, the saturated 1,4-diaza-2,5- diborine was determined to be quite similar to cyclohexane; the chair conformation observed in the X-ray crystal structure of235 180 and the stereochemistry of substituted derivatives177 resembled cyclohexane. However, the highly reactive nature ofthe BN- heterocycle was in marked contrast to the hydrocarbon analog; derivatives of 235 were often hydrolytically unstable. 235 Figure 30. Saturated 1,4-diaza-2,5-diborocyclohexane 235 is isolectronic with tetramethyl cyclohexane. The generation of partially oxidized 1,4-diaza-2,5-diborine heterocycles has been readily achieved via the dimerization of various eN-containing moieties that are tethered by two borane groups (Figure 31). Examples include dimerized isocyanide, imidazole, and pyridyl groups to give the corresponding heterocycles 236,237, and 238, respectively. Hesse and co-workers prepared the first dimer of type 236 (R = Ph, R' = Et) via reaction of phenylisocyanide with triethylborane. 182 The condensation reaction was accompanied by the migration of an ethyl group from boron to carbon. This initial work and subsequent studies showed that the migration of an second R' group from boron to carbon occurred upon heating. 183-185 Variation in the R' group was achieved by 236 78 Carter and co-workers,186 and later Bresadola et aI., 187 via the reaction of BzH6 with isocyanides to furnish 236 in which R' = H. Hesse and co-workers determined that HCN reacted with BEt3 to afford 236 where R = H,188 though there has been no reported synthesis of236 where both R and R' are hydrogen. Recent examples by Casanova and Hahn have examined the rearrangement chemistry of derivatives of 236.189-190 Me Me ci c;L- +N h BR2 N BR2I I ... • I I R2~1J R2~1) Me/ Me 237 237' Figure 31. Head-to-tail dimerization o[CN groups to generate 1,4-diaza-2,5-diborine derivatives. Contreras, Wrackmeyer and co-workers formed borane-bridged head-to-tail imidazole dimer 237a via the high-temperature reaction of imidazole-borane adduct 239 in the presence of Mel/AI (Scheme 71),191 Diaza-2,5-diborine 237a was formed as a separable mixture with the head-to-head isomer, 1,3-diaza-2,5-diborine 237b. The X- ray crystal structure of 237a revealed the 1,4-diaza-2,5-diborine core to be close to planar, which was attributed to packing effects. The B-N bond length of 1.55 Awas shorter than expected for a dative a-bond and was closer in length to a typical N(spz)- B(Sp3) bond. This structural data, coupled with NMR spectroscopic data, indicated a significant contribution from the carbenoid resonance form 237' .192 239 Me/[.N' 320°C +N~BH2 .. I I + [Mel,AI] H2~'-.'lJJN+ - H2 \ /N /) Me/ 237a Scheme 71. Fonnation of237a and 237b from imidazole-borane 239. Okada, ada, and co-workers selectively formed a derivative of 237 substituted 79 with mesityl groups at boron (R = 2,4,6-trimethylphenyl), and they determined via X-ray crystallography that the bulky mesityl groups force the 1,4-diaza-2,5-diborine core into a boat-like conformation with an elongated B-N bond (~1.64 A).193 Siebert and co- workers, I94 and later Hill and co-workers 195 reported the synthesis of derivatives of 237 via unexpected dimerization ofimidazoles, suggesting the formation of237 is thermodynamically favorable. A related dimerization was observed in dialkyl(2-pyridyl) boranes to form the 1,4-diaza-2,5-diborine scaffold 238 (Figure 32). In the characterization of diethyl(2- pyridyl)borane, Terashima and co-workers noted that the compound displayed a high melting point (205-206 DC) and mass spectrometry showed a prominent peak at m/z 294, consistent with dimer 238 (R = Et, molecular formula CI8H28B2N2). 196 Hodgkins and Powell determined that the dimerized product was present in two isomeric forms, the head-to-tail 1,4-diaza-2,5-diborine 238 and head-to-head 1,3-diaza-2,5-diborine 238' (R = Me, Figure 32).197-198 In fact, isomer 238' (R = Me) was found to be the major product of the reaction of2-lithiopyridine and bromodimethylborane at low temperature. Wright and co-workers determined via IH and lIB NMR that isomer 238' (R = Me) is 80 quantitatively converted to 238 in 30 minutes when refluxed in toluene-ds, suggesting 238 was the thermodynamic product while 238' was kinetically favored. 199 R =Me Figure 32. Isomerism in the dimerization of2-pyridyl boranes. The X-ray crystal structure obtained by Murafuji, Sugihara, and co-workers unambiguously established the identity of dimerized diethyl-2-(3-methyl)pyridyl borane and demonstrated that the 1,4-diaza-2,5-diborine core was planar and possessed long intra-ring B-N and B-C bonds (1.61 and 1.62 A, respectively).20o Another route to 1,4-diaza-2,5-diborines has been detailed by Paetzold and co- workers.201-202 The reaction of 3-membered heterocycle 240 (Scheme 72) with 2,6- dimethylphenyl isocyanide was shown to form monomeric 4-membered ring 241. However, when a less bulky isocyanide was added to 240, the formation of dimeric 1,4- diaza-2,5-diborine 242 was observed. The compound was found to be relatively stable and was structurally characterized by X-ray crystallography. Due to the strained structure incorporating bulky substituents at several positions, all three rings were found to be slightly out of plane with long intra-ring bond distances. tsu I N tBu.... B-'S·tsu 240 1.4. Summary tSu I Ar-N::C N • tBu-S' 'S-tSu 11 Ar .... N 241 Ar = 2,6-Me2C6HS Met tSu N ' Su tSu , ,I /Me-N::C S-----,-'l B-N 240 • I I I I /N-B... -::::-'-S, tSu tB~ ~ tSu Me 242 Scheme 72. Ring-opening of240 with isocyanides. 81 Over the last half-century, interest in the fundamental consequences ofB-N incorporation in heterocyclic compounds has led to a wide array of synthetically available motifs based on the azaborine and diazadiborine cores. Azaborine and diazadiborine can be considered to lie on the continuum between organic benzene and its "inorganic" counterpart, borazine. The physical properties, chemical reactivity, and computational analysis of azaborine and diazadiborine suggest that most of these hybrid organometalloidal heterocycles display significant aromatic character. The last decade has been a renaissance in the synthesis of monocyclic azaborines, which was fueled by the replacement of older methods with mild, efficient protocols. Currently there are several routes to the monocyclic azaborine motif, yet the incorporation ofadditional functionality has been relatively unexplored. Various polycyclic motifs have become more readily available since the 1960s, and their chemistry is well understood. The preparation of non-aromatic azaborine derivatives has been demonstrated, and in some 82 cases these have been developed as precursors to the corresponding aromatic heterocycle. Several isomers of azaborine and diazadiborine have been prepared, yet many of these are constrained to non-aromatic derivatives. The application of aromatic BN heterocycles to areas such as material science and medicine will rely on efficient, general synthetic methods that have yet to be fully realized. 1.5. Bridge to Chapter II This chapter reviewed the literature on azaborine and diazadiborine heterocycles as benzene analogs. Chapter II will describe the synthesis, characterization, and reactivity of 1,2-azaborine derivatives containing unprecedented functionality at the boron position. Chapter II contains previously published and unpublished co-authored material. The synthetic efforts discussed in Chapter II will be expanded to include the synthesis of the parent compound, 1,2-dihydro-l ,2-azaborine, and will include biochemical and spectroscopic studies on 1,2-dihydro-l ,2-azaborine as it relates to benzene. Chapter III contains previously published co-authored material. Chapter IV will discuss the synthesis, characterization, and photophysical properties of 1,2- azaborines that have been incorporated into conjugated organic scaffolds. Chapter IV contains previously published co-authored material. Chapter V will provide a short introduction into the chemistry of nitrated lipids and then discuss the work accomplished in this field as a member of the Branchaud group. Chapter V contains previously published and unpublished co-authored material. Chapter VI will summarize the work discussed in earlier chapters. Appendices A-D discuss experimental details related to chapters II-V, and contain previously published and unpublished co-authored material. 83 84 CHAPTER II EXPANDING THE SCOPE OF 1,2-AZABORINE SYNTHESIS VIA NUCLEOPHILIC SUBSTITUTION AT BORON 2.1. General Overview This chapter discusses the generation of a family of boron-substituted 1,2- dihydro-l,2-azaborines which are derived from a versatile 2-chloro-l ,2-azaborine intermediate. This excerpt includes material published as Marwitz, A. J. V.; Abbey, E. R.; Jenkins, J. T.; Zakharov, L. N.; Liu, S. - Y. "Diversity though isosterism: the case of boron-substituted 1,2-dihydro-l,2-azaborines," Org. Lett. 2007,9,4905-4908. The X- ray crystallographic data was collected and analyzed by Dr. Lev Zakharov. Jesse Jenkins prepared some of the chemical compounds and Eric Abbey established some of the early protocols. Otherwise all experimental work was performed by me. This excerpt was written entirely by me. The discussed work also includes material published as Marwitz, A. J. V.; McClintock, S. P.; Zakharov, L. N.; Liu, S. -Y. "BN benzonitrile: an electron-deficient 1,2-dihydro-l,2-azaborine featuring linkage isomerism," Chern. Cornrn. 2010,46, 779- 781. The experimental work was conducted by me with the exceotion of the X-rav .... .,..L"; crystallographic data, which was collected and analyzed by Dr. Lev Zakharov. 85 Computational studies were performed by Dr. Sean McClintock. This excerpt was written entirely by me. This chapter includes the synthesis and characterization of cationic 1,2- azaborines. The excerpt includes unpublished co-authored material with Dr. Lev Zakharov and Jesse Jenkins. X-ray crystallographic data was collected and analyzed by Dr. Lev Zakharov. Some of the presented chemical compounds were first prepared and characterized by Jesse Jenkins. Otherwise I performed all the experimental work. The co-authored excerpt was written entirely by me. This chapter discusses spectroscopic studies of 1,2-azaborine published as Tanjaroon, C.; Daly, A.; Marwitz, A. 1. V.; Liu, S. - Y.; Kukolich, S. "Microwave measurements and ab initio calculations of structural and electronic properties ofN-Et- 1,2-azaborine," J. Chern. Phys. 2009, 131,22431211-224312/9. Compounds were prepared by me and spectroscopic characterization was performed by Tanjaroon, Daly, and Kukolich. The co-authored excerpt as presented here was written by me. Professor Shih-Yuan Liu has provided editorial assistance and scientific guidance for all material (published and un-published) covered in this chapter. 2.2. Introduction 1,2-Dihydro-1,2-azaborine is a six-membered aromatic heterocycle that is related to benzene via replacement of a C=C unit in benzene with an isoelectronic B-N bond pair. The exploration of the chemistry of 1,2-dihydro-1 ,2-azaborine (hereafter referred 86 to as 1,2-azaborine) could offer opportunities in a broad range of applications from drug design to conjugated organic materials. Whereas polycyclic derivatives of 1,2-azaborine have been explored extensively, 1-4 monocyclic 1,2-azaborines have received significantly less attention, presumably due to limited synthetic access. Dewar and White pioneered the first syntheses of 1,2-azaborines in the early 1960s and demonstrated that these compounds have substantial aromatic character.5-6 More recently, Ashe and co-workers have developed two complementary synthetic strategies for monocyclic 1,2-azaborines: (l) a ring expansion of lithium azaborolides7 and (2) a ring-closing metathesis (RCM)- oxidation sequence (Scheme 1).8 These protocols have provided novel 1,2-azaborine structures that have been studied primarily as tunable ligands in organometallic complexes.9- 12 R' Li+ /8~'\8B, R ~wR' ReM (wR1 DDQ (N,R1 I .. I I .. I ~B'R B'R ~ B'R Scheme 1. ReM-oxidation (top) and ring-expansion (bottom) routes to 1,2-azaborines. Despite the recent advances in the synthesis ofmonocyclic 1,2-azaborines, significant synthetic challenges remained when we began our work. Specifically, the scope with respect to the exocyclic boron substituent "vas limited to carbon- and oxygcn- based groups. In contrast, the ubiquity of the phenyl motif in chemistry is due in part to the availability of countless substituted derivatives. If the unique features of 1,2- 87 azaborine as a benzene mimic are to be fully realized, access to a wide array of 1,2- azaborine derivatives must be achieved. 2.3. Generation of a Versatile 2-Chloro-l,2-azaborine We envisioned that an advanced 1,2-azaborine intermediate bearing an electrophilic boron atom would serve to provide a wide array of boron-substituted 1,2- azaborine structures via nucleophilic displacement of an appropriate leaving group. The RCM-oxidation protocol developed by Ashe avoids the use of nucleophilic reagents and thus would not likely interfere with an electrophilic B-Cl bond. Therefore we prepared the bisallyl aminoborane 1 by Ashe's established method and subjected it to Grubbs' first-generation catalyst ((CY3Ph(PhCH)RuCh). Gratifyingly, ring-closed heterocycle 2 was readily produced in the reaction and was isolated in 66% yield by vacuum distillation (Scheme 2). ~N,Et 2% (CY3Ph(PhCH)RuCI2 (wEt I a I I ~B'CI 66% B'CI 1 2 Scheme 2. Ring-closing of aminoborane 1 to generate BN-heterocycle 2. The aromatization of 2 to 1,2-azaborine 3 proved to be more challenging (Table 1). Our initial attempts using stoichiometric oxidant 2,3-dichloro-5,6-dicyano-1,4- benzoquinone (DDQ) produced the desired B-Cl 1,2-azaborine 3, albeit in low yield (Table 1, entry 1). However, screening a series of heterogeneous catalysts showed that palladium can serve as a catalyst for this transformation (entry 2). The catalytic oxidation of 2 to 3 proceeds readily without the addition of a stoichiometric oxidant. 88 Therefore it seems likely that the elimination of H2 occurs to regenerate the Pd. With this in mind, the addition of a hydrogen acceptor (i.e., cyclohexene) as solvent was explored, leading to improvements in the yield (entry 3). A survey of transition metals reveals that Pd black catalyzes the aromatization of 3 most efficiently (entries 3-6). Finally, we determined that a homogeneous Pd source is ineffective in mediating this transformation (entry 7). Table 1. Survey of Aromatization Conditions for Heterocycle 2 eN'Et oxidation eN'EtI I .. IB....CI conditions ::::,.... B....CI 2 3 Entry Conditions Yielda (%) 1 1 equiv. DDQ, pentane, 35°C, 24 h 14 2 Pd/C (20 mol%), pentane, 80°C, 16 h 31 3 Pd/C (20 mol%), cyclohexene, 80°C, 16 h 43 4 Ru/C (20 mol%), cyclohexene, 80°C, 16 h 1 5 RhIAb03 (20 mol%), cyclohexene, 80°C, 16 h 23 6 Pd black (20 mol%), cyclohexene, 80°C, 16 h 75 7 Pd(PPh3)4 (10 mol%), benzene, 80°C, 16 h 0 a Determined by liB NMR analysis versus a calibrated internal standard (see Appendix A). Somewhat unfortunately, a small amount of reduced compound 4 was present in all explored oxidation conditions (Scheme 3). Also disappointing was the observation that side-product 4 was not effectively separated from 3 by vacuum distillation, nor were these compounds found to be particularly stable to silica gel chromatography. In a testament to the increased chemical stability offully aromatic heterocycle 3 relative to non-aromatic 4, it was detennined that the reaction of an alkynyl Grignard at low temperature occurred almost entirely at the B-Cl bond of 4 in the presence of 3. This provided a means of purifying 1,2-azaborine 3, wherein the mixture of3 and 4 was reacted with phenylethynylmagnesium bromide to selectively generate 5 (Scheme 3). Pd black 89 Purified 1,2-azaborine 3 was obtained via distillation, whereas 5 was left behind as a viscous oil. .. [(~~Et + (fEtj ~ B'CI B'CI 3 4 75:25 j 0.4 equivBrMg - Ph (~~Et .. distillation [(~~Et + (~~Et ]~ B 57% ~ B, B 'CI isolated CI ~ 3 3 5 Ph Scheme 3. Purification strategy for 1,2-azaborine 3. Heterocycle 3 serves as a general precursor to B-substituted 1,2-azaborines (Table 2). Displacement of the chloride in 3 occurs readily in the presence of alkyl- (entry 1), vinyl- (entry 2), aryl- (entry 3), and alkynyl-based (entry 4) nucleophiles. 13 Furthermore, heteroatom substitution also proceeded smoothly, resulting in the isolation of nitrogen-, oxygen-, phosphorus-, and sulfur-substituted 1,2-azaborines (entries 5-8). Treatment of 3 with Superhydride furnished the first monocyclic 1,2-azaborine containing the unique B-H bond (6i, entry 8). Compound 6i is stable to silica gel chromatography. A number of the compounds in Table 2 resemble aromatic structures of significance in chemistry. For instance, the vinyl-substituted 1,2-azaborine 6b is a heteroaromatic derivative of styrene. The alkynyl-substituted derivative 6d is an isoelectronic analog of diphenylacetylene (tolan). Intriguingly, phosphorus-substituted 6h is an isoe1ectronic analog oftriphenylphosphine. Hence, this synthetic protocol can 90 provide structures of potential value to polymer sciencc, organic materials, and catalysis. Table 2. Synthcsis of B-Subslilllted 1,2-Azaborines from 3 (~,Et Nu... (~,Et ::::,... B'CI ::::,... B'Nu 3 6 Entry Nllcleophile (Nu) Product I Li-Bu 6a 2 Li-vinyl 6b 3 BrMg-Ph 6c 4 BrMg - Ph 6d 5 Li-NMe2 6c 6 K-OtBu 6f 7 K-SBn 6g 8 K-PPh2 6h 9 LiBEt3 -H 6i " Isolatcd yield. Yielda (%) 79 50 76 83 66 71 gO 66 92 To demonstrate the utility of our synthetic method toward drug design, we have prepared 7, which is isoelcctronic with methyl2-ethylphenoxyacetate 8 (Scheme 4). Compound 8 and its derivatives havc dcmonstrated potent hypolipidemic activity in animal stlldics. 14 Treatment of 1,2-azaborine prccursor 3 with mcthyl glycolate 9 in the prescncc of triethylamine furnishes 7 in good yield. Expcrimcntal details regarding thc synthesis and characterization of compounds 2-8 can be found in Appendix A. ( N,Et isoelectronic o:Et , < >1 ::::,... B'Ol(oMe ::::,... 01(oMe o 0 ~OMe HO II °9 NEt3 85% .. 7 8 Scheme 4. Synthesis of I ,2-azaborinc 7, isoclcctronic analog of hypolipidemic agent 8. 91 2.4. The Synthesis and Coordination Chemistry of BN-benzonitrile In our continued efforts to create diversity of important aromatic structures through BN/CC isosterism, we recognized that 1,2-azaborines bearing electron- withdrawing boron substituents are still elusive. In particular, benzonitrile structures have attracted our attention because oftheir wide utility as biologically active agents l5 and as ligands in transition metal complexes. 16 We were therefore interested in generating and exploring the chemistry of a 1,2-azaborine analog of benzonitrile (Figure I). isoelectronicRe)~CN ~N<=<========::::::» R- I~B'CN benzonitrile BN-benzonitrile Figure 1. Benzonitrile and isoelectronic 1,2-azaborine analog. Benzonitriles are commonly synthesized from aryl halides via the Rosenmund von Braun reaction using stoichiometric amounts of copper(I) cyanide. I? More recently, transition metal-catalyzed methods for cyanation of aryl halides have been developed. 15 We envisioned that nucleophilic displacement of chloride from B-CII,2-azaborine 3 using cyanide would efficiently generate BN-benzonitrile 10 (Scheme 5). We believed NaCN could serve as a suitable nucleophile to yield the desired BN-benzonitrile 10. However, treatment of3 with NaCN resulted in no reaction, even upon heating. After screening a variety of conditions, we determined that the addition of AgCN to a solution of31ed to the immediate precipitation of AgCI and quantitative formation of10 as an air- and moisture-sensitive clear and colorless liquid. IS 92 The cyanide anion is an ambident nucleophile,19 and as such, it was unclear whether the product formed was BN-benzonitrile 10 or BN-benzoisonitrile 10' (Scheme 5). To determine the connectivity of 10, we treated precursor 3 with labeled AgBCI5N. Isotopic enrichment permitted the observation of the nitrile carbon as a broad quartet (6 126 ppm, q, IJBC = 85 Hz) in the BC NMR spectrum due to coupling with the liB atom (S = 3/2). The 15N NMR spectrum shows a sharp doublet eleN = 15 Hz), consistent with coupling to the BC nucleus. IR spectra of 10 and 10' were calculated at the DFT B3LYP/ DZVPZ level (see Appendix A). Whereas the calculated spectrum of 10 shows a strong vibration for the C=N bond at 2190 em-I, the corresponding calculated vibration in 10 is extremely weak at 2300 em-I, providing another distinction between 10 and 10'. The experimentally observed IR spectrum of 10 does not exhibit a peak in the expected stretching frequency of cyanides around 2200 em-I. Thus, the experimental NMR and IR data are consistent with the formation of 10, not 10'. The calculated relative zero- point energies (ZPE) of 10 and 10' indicate that BN benzonitrile 10 is thermodynamically more stable than its isomer 10' by 3.7 kcal mor l. Nucleus Independent Chemical Shift (NICSio calculations suggest nitrile 10 (NICS(1) = -7.55) is slightly more aromatic than isonitrile 10' (NICS(1) = -6.96). 93 (~,El NaCN • No Reaction~ B.... C1 THF/1 3 (N'Et AgCN (~,Et not (~,Et~ s.... CI •CH2CI2• rt ~ B .... ~ B, + C-:"N N,-99% "C3 10 10' Scheme 5. Synthcsis of BN-bcnzonitrile 10. To gain additional insight into the electronic structure of 10, we calculated the electrostatic potential surface (ESP) of 10 and contrasted it with the ESP for the BH- substituted I ,2-azaborine 6i. Figure 2 illustrates that in BN-benzonitrile 10, most of the negative charge (highlighted by the red color) is localized at the electron-withdrawing eN substituent. In contrast, the ESP map of 6i indicates a greater localization of negative charge on the I ,2-azaborine ring. Figure 2. Electrostatic potential maps at the 0.002 elcctron/a.u.3 density iso-contour level with an electrostatic potential rangc from -13.6 to 54.4 kcal mor' for 1,2-azaborines 10 and 6i. Blue is positivc potential (repulsive for thc positive charge), red is negative potential (attractive for the positive charge) and green represents near zero potential. Analysis of substituent effects on the rr:-elcctron density of aromatic molecules has been achieved using NMR spectroscopy.2J In particular, studies by Herberich et al. 22 94 and Fu et al.Z3 have shown that electron donation by boron-bound substituents in boratabenzenes, a family of boron-containing heterocycles similar to 1,2-azaborines, leads to upfield shifts of the ortho and para resonances in the IH and BC NMR spectra. The IH and BC NMR chemical shifts observed for BN benzonitrile 10 (Table 3) suggest that 10 is an electron-deficient 1,2-azaborine. The calculated HOMO and LUMO ofBN benzonitrile 10 are presented in Figure 3. The HOMO orbital coefficients are largest at the ortho (3) and para (5) positions of the heterocycle with additionaln-electron density predominantly localized at the nitrogen atom of the cyano group. The LUMO of 10 shows a relatively large coefficient at boron, which is consistent with the electrophilic character of boron. Also of note is the fact that the LUMO is antibonding with respect to the CN n bond whereas the HOMO of 10 has bonding character. Table 3. IH and BC NMR Shifts ofB-Substituted 1,2-Azaborines Boron substituent Hortho Hpara NMez 6.21 5.72 H 6.84 6.40 CN 6.99 6.64 Experimental chemical shifts [ppm] in CDzClz. Cortho 124 131 131 Cpara 105.5 112.3 115.1 We next explored the coordination behavior ofBN benzonitrile 10. When 10 was treated with (MeCN)3Cr(CO)3 in THF at 60°C, we observed evidence for the formation of the piano-stool complex 11 by IH and liB NMR as a minor component of a complex mixture (Scheme 6). The upfield chemical shifts in the IH and llB NMR spectra of the reaction are consistent with YJ6 coordination of the 1,2-azaborine ring. lD However, upon work-up we were only able to isolate complex 12 as yellow crystals in low yield. 95 LUMOHOMO 5(~,Et "'" B, 3 C"'N 10 Figure 3. HOMO and LUMO of 10 calculated at the B3LYP/DGDVP2 level. 10 (MeCNhCr(COh THF, 60°C (~,Et~ B'N, ~C .... Cr(CO)5 12 isolated N,Et (C);B-[CNl I OC/C\",CO CO 11 observed in solution Scheme 6. Complexation of 10 with chromium(O). Crystals of 12 suitable for single-crystal X-ray analysis were grown from a saturated pentane solution. The X-ray structure of 12 revealed that the original BCN linkage in 10 underwent linkage isomerization under the reaction conditions (Figure 4),24-26 The structure is nearly co-linear through the B-N-C-Cr group (LB(1)-N(1)-C(6) = l72.4(3t, LN(l )-C(6)-Cr( 1) = 179.3(3t), indicating sp hybridization for both C(6) and N(1), The slight bend in the B(1)-N(1)-C(6) angle (7.6°) is consistent with a weak M(dJt)~CNRback-bonding inieraciion, simiiar to ihat observed in arylisocyanidechromium pentacarbonyl complexes (Cr(CO)5(CNAr».27-29 The B(1)- 96 N(l) bond (B(l)-N(l) = 1.489(4) A) is comparable to the boron-isonitrile bond in Cr(CO)s(CNB(CH(SiMe3)2)2) (B-N = 1.475(6) A),30 which to the best of our knowledge is the only other reported crystal structure of a trigonal planar boron atom bound to an isocyanide. The N(l)-C(6) bond distance in 12 (1.153(4) A) is similar to the NC bond length observed in Cr(CO)s(CNB(CH(SiMe3)2)2) (N-C = 1.159(5) A),30 as well as other reported Cr(CO)s(CNAr) structures (N-C = 1.151(3) A)?7-29 The C(6)-Cr(l) bond distance (1.981(3) A) in 12 is also very similar to the ones exhibited by (CO)sCr(CNB(CH(SiMe3)2)2)3o (C-Cr = 1.971(4) A) and (CO)sCr(CNAr)27-29 complexes (C-Cr = 1.968(3) A. Electron-rich pentacarbonyl(isocyanide)-chromium(O) complexes show long NC-Cr distances (e.g., 2.000(3) A in (CO)sCr(CNNH2))31 whereas electron-withdrawing groups on the cyano moiety shorten the C-Cr distance (e.g., 1.883(3) A in CO)sCr((CNCN)).32 The observed structural parameters are consistent with a strong contribution of the resonance form A relative to B in complex 12 (Figure 4). We are interested in the effects of the electron-withdrawing NCCr(CO)s substituent on the intra-ring bond distances of the six-membered BN heterocycle. We determined that the intra-ring bond distances to boron in 12 are the shortest reported for a 1,2- azaborine (N(2)-B(l) = 1.412(4) A and B(l)-C(7) = 1.486(5) A), consistent with substantial positive charge at boron. Complete structural data for 12 are presented in AppendixA. [Cr(CO)sCNrNa+ THF, rt 99% 97 , . I If'--" '"I , NI, -J , ~---&--l--~:--:"l--(J) / Nl fill";,), .-J'f\ Et ~t C S - N:::C-Cr(CO)5 CE!.=N=C=Cr(CO)5 A B Figure 4. ORTEP illustration of 12, with ellipsoids drawn at the 35% probability level. The low-yielding synthesis of 12 outlined in Scheme 7 prevented us from fully characterizing complex 12. Thus, we sought to independently synthesize 12 via alternative routes. Gratifyingly, we discovered that treatment of 1,2-azaborine precursor 3 with sodium pentacarbonyleyanochromate33 furnished the desired adduct 12 in quantitative yield (Scheme 7). . (~,Et ~ B'N~ 'C 12 'Cr(CO)s Scheme 7. Alternate route to 12. IH and liB NMR spectra of the material obtained by Scheme 7 were consistent with the previously prepared material via Scheme 6. The I3C NMR spectrum showed the isonitrile carbon as a sharp singlet at 189.2 ppm as well as two unique carbonyl groups, consistent with the cis (215.4 ppm) and trans (217.6 ppm) CO ligands. Finally, in the IR spectrum of 12, the observed C=N stretching frequency at 2130 em-I is 98 comparable to those observed in related (CO)sCr(CNAr) complcxes (2121 cm- J),29 but is at a higher wavenumber than (CO)sCr(CNB(CH(SiMe3)2)2) (2113 cm- i ).30 The CsO vibrations for 12 are at 2051, 1990, and 1954 cm- I . These values are in good agreement with known (CO)sCr(CNAr) complexes.27-29 The experimentally determined IR spectrum of 12 is also in accord with its calculated spectrum (OFT B3LYP/ OZVPZ level, see Appendix A). The mechanism for the formation of 12 in Scheme 6 remains unclear. We hypothesize that reaction oflO with Cr(CO)s(L) or Cr(CO)6 prescnt or generated in the reaction mixture could lead to 12. To test this hypothesis, we reacted BN benzonitrile 10 with Cr(CO)6 in THF at 60°C and determined that 12 is generated in 23% yield. 2.5. Cationic B-substituted 1,2-Azaborines Thc previous scctions discLlsscd thc substitution of anionic nuclcophilcs at the reactive B-CI bond of I ,2-azaborinc 3. Wc hypothesized that activation to an even more electrophilic intcD11cdiatc might makc the boron atom susceptible to nucleophilic attack by neutral nucleophiles (Schcme 8). The resulting 1,2-azaborine adducts would be positivcly charged, opcning the way to the study of a novel class of cationic boron heterocycles. :; 1,2-azaborine X = activating group cation L = neutral nucleophile Scheme 8. Strategy for generating cationic 1,2-azaborines. 99 The reaction of B-CI J,2-azaborine 3 with AgOTf gratifyingly produccd B-OTf 1,2-azaborine 13, which was distilled under vacuum in 59% yield as an extremely air- and moisture-sensitivc liquid (Scheme 9). In fact, we noticed that the residue of compound 13 on the distillation apparatus fumed instantly whcn exposed to air. Furthermorc, solvcnts such as THF were incompatiblc with I ,2-azaborine 13. The solidification of the entire solution of 13 in THF over the course of a fcw hours led us to conclude that Lewis acid-catalyzed polymerization of the solvent was taking plaee.34 Thc enhanced Lewis acidity of 13 is likely due to the triflate substituent at boron which is generally an excellent leaving group. 1,2-Azaborine 13 was characterized by IH, liB, and 13C NMR spectroscopy as well as IR spectroscopy. AgOTf (WEt PhH, rt ~ ~ S'OTf 59% 13 Scheme 9. Synlhcsis of 13. The reaction of 13 with nelltral nucieophiles was then examined, the results of which arc summarized in Table 4. Pyridine-substituted 1,2-azaborines 14a (entry 1) was formed quantitatively when 4-phenylpyridine was added to 13. Phosphine-substituted I ,2-azaborine cation 14b (entry 2) readily formed upon reaction ofPMe3 with 13. The reaction of phosphine oxides and pyridinc N-oxides with 13 readily provided the cationic adducts 14c and 14d, respectively (entries 3 and 4). The intriguing formation of DMSO adduct J4e (entlY 5) was achievcd readily. 100 Table 4. Synthesis of 1,2-Azaborine Cations 14a-e ( ~Et . ( ~Et ;,r N Nucleophlle (Nu) '?' N I .. I ~ B....OTf ~ B... Nu 13 Entry Nuc1eophile (Nu) 1 4-phenylpyridine 2 PMe3 3 Ph3PO 4 Pyridine N-oxide 5 MezSO a Isolated yield. Product 14a 14b 14c 14d 14e 14 Yielda (%) 97 99 89 99 95 We have fully characterized compounds 14a-e by lB, lIB, and 13e NMR spectroscopy. Phosphorus-containing compounds 14band 14c were further characterized by 31 p NMR spectroscopy. The NMR spectroscopic data were consistent with the assigned structures of 14a-e. Furthermore, X-ray crystallography confirmed the structures of 14a-d. The solid-state structure of 14a is presented in Figure 5 and reveals that the pyridyl nitrogen is bonded to the boron atom with the displacement of the triflate group as a non-coordinating anion. The exocyc1ic B-N bond length (B(1)-N(2) = 1.531(2) A) in 14a is significantly longer than the exocyc1ic B-NPhz bond in a 1,2-azaborine recently reported by Liu and co-workers (B-N = 1.486(2) A,35 which indicates weaker coordination of the pyridyl nitrogen relative to an amino substituent. The exocyclic B-N bond in cationic 14a is slightly shorter than the B-N bond in the charge-neutral borabenzene-4-phenylpyridine adduct (B-N = 1.551(3) A) reported by Fu and co- workers.36 In the latter example, the B-N bond is dative and is therefore elongated relative to 14a. The 1,2-azaborine ring in 14a is completely planar and is twisted by 101 approximatcly 50° relativc to thc pyridinc ring. Tn contrast, the phenyl ring of 14a is only slightly twisted relative to the pyridine ring (18°). There is a minor degree of bond length heterogcncity within thc pyridine ring, as the C(7)-C(8) bond (J .368(2) A) is slightly sholtcr than the C(8)-C(9) bond (1040 I(2) A). We wcre also intercsted in examining the structural featurcs of thc I ,2-azaborine ring in cationic 14a. The intra- ring B-N bond is short (B(I)-N(1) = 1.413(2) A), as is the intra-ring B-C bond (B(J)- C(4) = 1.496(2) A), consistcnt with an electron-dcficient 1,2-azaborine. Additional crystallographic information for 14a can be found in Appcndix A. (- 'i-----{ \ / '\. I -- \ ).1I">-----t \ ---1 I, ( !t / ? t1J\, I (/ ') Figure 5. ORTEP illustration or 14a, with thermal ellipsoids drawn at the 35% probability level (hydrogen atoms have becn omitted lor clarity). Bond distances (in A): B( I)-N( I) 1.413(2); B( I )-N(2) 1.531 (2); B( I)-C(4) 1496(2); C(4)-C(3) 1.369(2); C(3)-C(2) 1.408(3); C(2)-C(l) 1.358(2); C( I)-N( I) 1.3736( 19); C(7)-C(8) 1.368(2); C(8)-C(9) 1.40 I(2); Torsion angles: I ,2-azaborine-pyridinc 50.5°; pyridine-phcnyl 18.0°. The solid-state structure of phosphinc-substituted 14b is illustrated in Figure 6. The structural parametcrs of 14b arc similar to thc obscrvcd structure of the trimethylphenyJphosphonium cation/7 with which 14b is isoelcctronic. Thc B-P bond in 14b is long (B(l)-P(l) = J.947(3) A) relative to the Cnryl-P bond in trimethylphosphonium iodide (CHryl-P = 1.797(6) A) which is likely due to the increased van del' Waals radius of boron (1.92 A) relative to carbon (1.70 A).3S The 1,2-azaborine 102 ring is planar and the intra-ring bond distances arc virtually identical to those of pyridyl- substituted 14a. The phospholUS atom in 14b is pyramidal, with the sum of the three Me-P-Me angles equal to 320°. The sum ofMe-P-Me angles in the corresponding PhPMe/r was 327°.37 Additional crystallographic infonnation for 141> can be found in Appendix A. ",t' .~) rz..~ ( I Figure 6. ORTEP illustration of 14b, with thermal ellipsoids drawn at the 35% probability level (hydrogen atoms and triflate counlcrion have been omitted for clarity). Bond distances (in A): B( J )-N( I) 1.419(3); I3(I)-P(I) 1.947(3); I3(1)-C(4) 1.492(3); C(4)-C(3) 1.368(3); C(3)-C(2) 1.402(3); C(2)-C(l) 1.358(3); C( I)-N( 1) 1.365(3). The crystal structures of 14c and 14d are presented in Figures 7 and 8, respectively. In 14c, the phosphine oxide is bound to boron through oxygen. The B(l)- O( I) bond is long (1.433(2) A) relative to typical B(Sp2)-OR bonds (J .35-1.38 A),39 consistent with the difference between dative versus covalent bonding. Despite this observation, the C(4)-B(1 )-O( I)-P( I) dihedral angle of 18° indicates a somewhat favorable Jt-overlap between oxygen's lone-pair and boron's p-orbital. Furthem10re, the long P( I)-O( I) bond in 14c (1.5563(J 3) A) relative to typical phosphine oxides (1.48- 1.50 Ai9 indicates a significant reduction of the double-bond character in the P-O hond upon coordination to boron. The structural parameters of 14d arc virtually identienl to 14c with regard to the 1,2-azaborine ring. An examination of the relevant bond lengths 103 in the exoeyelie pyridine N-oxide substituent again indicates very little Jt-overlap between oxygen and boron. However, the C(4)-B(1 )-0(1 )-P(I) dihedral angle in 14d of approximately 3° is ideal for Jt-overlap betwecn boron and oxygcn. Intercstingly, the pyridine ring is twisted completely pcrpcndicular to the I ,2-azaborinc ring. ( /' \ • 'I,' 1 Figure 7. ORTEP illustration of 14c, with thermal ellipsoids drawn at the 35% probability level (hydrogen atoms and triflate countcrion havc been omillcd for clarity), Bond distances (in A): B(I )-N(l) 1.420(3); B( I)-O( J) ] .433(2); B( I)-C(4) 1.496(3); C(4)-C(3) 1.369(3); C(3)-C(2) 1.403(3); C(2)-C( I) 1.357(3); C( I)-N( I) 1.368(2); P(l )-O( I) J.5563( 13); Torsion anglcs: C(4)-B( I)-O( I)-P( J) 18,0°. ~ \ \ '~ " ' (' NI , '(;{ ',\ ' /\,\I~ , I') I I ". ',) \, (, I /, Figure 8. ORTEP illustration of 14d, with lhermal cllipsoids drawn althc 35% probability level (hydrogen aloms and trillate counlcrion have becn omillcd for clarity). Bond distances (in A): B(l)-N(J) l.4l4(3); B(1)-0(!) !.429(3); B(!)-C(01) !.0192(3); C(4)-C(3) !.363(3); C(3)-C(2) 1.408(4); C(2)-C(1) J.349(4); C( J )-N( I) 1.37 J (3); N(2)-O(J) 1.383(2); Torsion angles: C(4)-B(J )-O( I)-N(2) 2.7°; 1,2- azaborine-pyridine 85.5° 104 Though we were unable to structurally characterize the DMSO adduct 14e via x- ray crystallography, a comparison of the lIB NMR spectra of 14e with compounds 14c and 14d led us to conclude that boron is likely bound to oxygen in 14e. In a continued effort to understand the effects that the exocyclic boron substituent has on the structure and electronics of the 1,2-azaborine system, we have prepared a series ofB-pyridyl 1,2-azaborine cations with various groups at the para position of the pyridine ring (Table 5).40 The phenyl-substituted derivative 14a (entry 1) was prepared in good yield as discussed above. We observed that the crystals of phenyl- substituted 14a were light-green in color and solutions of 14a appeared highly fluorescent. The absorption spectrum of 14a in CH2Ch showed a broad, featureless peak at 292 nm (c = 21869 M-Icm-I) as well as less intense bands at higher energy. In MeCN the major absorption was at 251 nm (c = 17202 M-Icm- I) with the lower energy absorption at 290 nm appearing as a shoulder peak. The fluorescence spectrum of 14a in CH2Ch showed an emission peak at 360 nm ( 22> 21 > 15. Phenyl-substituted 19 was 5.4 times more reactive than 15, while 119 methoxy-substituted 22 was 2.0 times as reactive as 15. B-Buty121 was 1.9 times more reactive than 15. These data indicate that the electron-deficient B-Cl derivative 15 is deactivated relative to the other derivatives, while more electron-rich groups facilitate EAS reactivity. Furthermore, the highly reactive nature of phenyl-substituted 19 relative to butyl-substituted 21 suggests that both inductive and resonance contributions affect EAS reactivity. Experimental details for the competition reactions and for the preparation of21, 22, and 23 can be found in Appendix A. Compound Relative Rate 15 R = CI 1 19 R = Ph 5.4 21 R = Bu 1.9 22 R = OMe 2.0 Figure 19. Relative rates of bromination for B-substituted 1,2-azaborines. 2.7. Conclusion In summary, we have developed a general method for the synthesis of a wide range of B-substituted 1,2-azaborines, including the first examples containing B- heteroatoms. The synthesis and coordination chemistry of an especially electron- deficient 1,2-azaborine, BN-benzonitrile, has been explored. We have also provided an efficient route to a novel class of cationic 1,2-azaborines. A systematic examination of the structural features of the 1,2-azaborine system has revealed that bond delocalization in the heterocycle is relatively unperturbed by exocyclic substituents. The use of 1,2- 120 azaborines as isoelectronic analogs of the ubiquitous benzene motif may provide new opportunities in the areas of drug discovery and material science. 2.8. Bridge to Chapter III Chapter III discusses the work toward the synthesis of the parent 1,2-dihydro- 1,2-azaborine, which is isoelectronic with benzene itself. The preparative methods discovered in Chapter II are coupled with the installation of a cleavable protecting group at nitrogen, leading to the first successful synthesis of 1,2-dihydro-1 ,2-azaborine. The comprehensive characterization of 1,2-dihydro-1,2-azaborine is explored, including rotational spectroscopy in collaboration with the Kukolich group at the University of Arizona. Experimental results are compared to high-level calculations performed by the Dixon group at the University of Alabama in order to elucidate the structural and electronic features of this fundamentally important molecule. The last section of Chapter III discusses a proof of principle protein binding study of 1,2-dihydro-1 ,2- azaborine in relation to benzene. 121 CHAPTER III SYNTHESIS AND CHARACTERIZATION OF 1,2-DIHYDRO-l,2- AZABORINE 3.1. General Overview This chapter discusses the synthesis, isolation, and characterization of 1,2- dihydro-1,2-azaborine. This excerpt includes unpublished material as well as material published as Marwitz, A. J. V.; Matus, M. H.; Zakharov, L. N.; Dixon, D. A.; Liu, S.-Y. "A hybrid organic/inorganic benzene," Angew. Chern. Int. Ed. 2009,48,973-977. The X-ray crystallographic data was collected and analyzed by Dr. Lev Zakharov. DFT calculations were performed by Myrna Matus and Professor David Dixon. Otherwise all experimental work was performed by me. The co-authored excerpt was written entirely byrne. This chapter also includes vibrational spectroscopy performed on 1,2-dihydro- 1,2-azaborine. This excerpt includes material published as Daly, A. M.; Tajaroon, C.; Marwitz, A. 1. V.; Liu, S. -Y.; Kukolich, S. G. "Microwave spectrum, structural parameters, and quadrupole coupling for 1,2-dihydro-I,2-azaborine," J Am. Chern. Soc. 2010,132,5501-5506. Vibrational spectroscopy and DFT calcuations were perfonned by Adam Daly, Chakree Tanjaroon, and Professor Stephen Kukolich. Otherwise all 122 experimental work was performed by me. The co-authored excerpt as presented here was written entirely by me. This chapter also includes a protein binding study of 1,2-azaborines. This excerpt includes material published as Liu, L.; Marwitz, A. J. V.; Matthews, B. W.; Liu, S. - Y. "Boron mimetics: 1,2-dihydro-1 ,2-azaborines bind inside a non-polar cavity of T41ysozyme," Angew. Chern. Int. Ed. 2009,48,6817-6819. The X-ray crystallographic data was collected and analyzed by Dr. Lijun Liu. Protein purification and crystal growth was performed by Dr. Lijun Liu. Professor Brian Matthews provided editorial input for this section. Otherwise all experimental work was performed by me. The co- authored excerpt as presented here was written entirely by me. Professor Shih-Yuan Liu has provided editorial assistance and scientific guidance for all material (published and un-published) presented in this chapter. 3.2. Introduction Benzene (C-C6H6) is arguably one of the most fundamentally significant small molecules in chemistry. First discovered by Faraday in 1825,1 the study of benzene introduced the basic concept of aromaticity and delocalization? In addition to its fundamental importance, benzene and its derivatives (arenes) are ubiquitous in chemical research with numerous applications ranging from biomedical research to materials science.3 Borazine (c-B3N3H6), the inorganic, isoelectronic relative of benzene, was first isolated in 1926 by Alfred Stock,4 and since then has also played a pivotal role in fundamental and applied chemistry. The isoelectronic and isostructural relationship ~~--------_._._- 123 between B-N versus C=C bonds has stimulated discussion regarding the aromaticity of borazine.5-7 In more applied fields, borazine serves as a precursor to BN-based ceramic materials. 8,9 In the area of chemical hydrogen storage, borazine has been implicated as an intermediate in the hydrogen release from ammonia borane. 10 While benzene and borazine have been thoroughly studied over the last 80 years, the hybrid "organometalloidal" structure containing carbon, boron, and nitrogen, that is, 1,2- dihydro-1,2-azaborine 1, has thus far eluded characterization (Figure 1). hybrid organic organometalloidal inorganic H I 0 (fH H'S... N'S... HI I~ S'H WN'S ... N'H I 1 H benzene 1,2-dihydro- borazine 1,2-azaborine ~~~ ~~ (1825) (1926) Figure 1. Benzene, borazine, and 1,2-dihydro-l ,2-azaborine 1. While the chemistry of polycyclic boron-nitrogen heterocycles is well understood,l1-13 monocyclic derivatives have been relatively unexplored. Dewar and White pioneered the chemistry of monocyclic 1,2-dihydro-1 ,2-azaborines (hereafter referred to as 1,2-azaborine unless referring to the parent compound 1) in the 1960s. 14-15 Recent contributions by the Ashe and Uu groups have expanded the scope of available 1,2-azaborines. 16-18 Yet the synthesis of the relatively simple heterocycle 1 remained unrealized 50 years after the first report of its attempted synthesis. 19 This chapter discusses the development of the first successful synthesis of 1,2-dihydro-1 ,2-azaborine 124 1. The in-depth characterization of 1 follows the synthetic discussion, and provides infonnation regarding its aromaticity in relation to benzene and borazine. Our experimentally determined structural and spectroscopic properties are consistent with values derived from high-level computations. Finally, a protein binding study is discussed which provides a "proof-of-principle" demonstration of the bio-mimetic potential of 1,2-azaborines. 3.3. Synthesis and Characterization of 1,2-Dihydro-l,2-azaborine We have reported the synthesis of 1,2-azaborines incorporating various heteroatoms at the boron position, including the B-H functionality of 1,2-dihydro-1,2- azaborine 1.18 We believed a comparable route to 1 would be possible via the incorporation of a protecting group at the nitrogen position of an advanced 1,2- azaborine. The synthesis of 1 was envisioned to occur from this intennediate in a two- step protocol (Scheme 1): 1) hydride substitution at boron would provide the B-H functionality, and 2) cleavage of the nitrogen protecting group would give 1. R = protecting group versatile intermediate Scheme 1. Retrosynthesis of 1 from a versatile 1,2-azaborine intermediate. The first nitrogen protecting group we screened was the benzyl group, which is a chemically robust group that can generally be cleaved without the use of strong acid or base,z° Ashe and co-workers demonstrated that B-phenyl1,2-azaborines are remarkably 125 resistance to hydrolysis and can even be treated with aqueous work-up.21 Therefore, to probe the viability ofN-benzyl deprotection, we synthesized B-phenyll,2-azaborine 2 (previously described in Chapter II, Scheme 13) and screened a variety of reaction conditions for the cleavage of the N-benzyl group of2 to N-H 1,2-azaborine 315 (Table 1). The deprotection ofN-benzyl groups is commonly achieved using heterogeneous Pd catalysts and H2.20 Unfortunately, we failed to observe evidence for the cleavage ofthe benzyl group using heterogeneous Pd (entries 1-5). Instead, we discovered that the 1,2- azaborine ring is prone to reduction under these conditions (4 in Table 1). The addition oftrimethylsilyliodide (TMSI) was ineffective at cleaving the N-benzyl group in 2 (entry 6).22 2,3-Dichloro-5,6-dicyanobenzoquinone (DDQ) has been shown to cleave benzyl groups,23 yet no reaction was observed with 2 (entry 7). Finally, oxidative debenzylation was attempted with ceric ammonium nitrate,24 but no product formation was observed (entry 8). Table 1. Survey of Debenzylation Conditions for Heterocycle 2 (~~Bn conditions.. (~~H or~ B'Ph ~ B'Ph 2 3 Entry Conditions 1 20 mol% Pd/C, 80°C, C6D6, 40 psi H2, 6 h 2 10 mol% Pd/C, 60°C, C6D6, 40 psi H2, 4 h 3 20 mol% Pd/C, 80°C, THF-ds, 1 atm H2, 14 h 4 10 mol% Pd(OH)2/C, 25°C, EtOH, 50 psi H2, 18 h 5 12.5 mol% Pd/C, 25°C, MeOH, excess HC02H, 48 h 6 excess TMSI, 60°C, CD2Ch then MeOH, 4 h 7 1 equiv. DDQ, 75°C, pentane, 4 h Q ") '" n...TU) r n...TO,\ '1-'= 0C l\.1-CNITT r-.. A 1 U '" eqUlv. \l'iJ.-'4 2~e\l'l 3/6,':'..J , IV I;; 1 tIT2V, '+ n Product 50% 4a 40% 4a 100% 4a no reaction degradationb no reaction no reaction no reaction a 'H NMR integration versus starting material. b llB NMR indicated the formation of a 4-coordinate boron-containing compound. 126 We next explored the synthetic availability of silicon-based protecting groups at the nitrogen position of 1,2-azaborine. The Ashe group has demonstrated the incorporation and facile removal of an N-trimethylsilyl (N-TMS) protecting group from a B-phenyl 1,2-azaborine?1 We therefore endeavored to produce the analogous B-H N- TMS 1,2-azaborine on the way to the parent 1,2-dihydro-1 ,2-azaborine 1. The reaction ofTMS-allylamine with allylboron dichloride (generated in situ from the transmetallation ofBCh and allyltriphenylstannane) gave a mixture ofproducts, including the desired bisallyl aminoborane 5 (Scheme 2). We were unfortunately unable to purify 5. ~N/TMS H + NEt3 ~N ....TMS unidentified ----.. I +hexanes/ ~B'CI side-products CH2CI2 -78°C 5 Scheme 2. Observation ofTMS-protected aminoborane 5. We next turned to the bulky triisopropylsilyl (TIPS) protecting group?O The improved stability of the TIPS protecting group permitted the formation of aminoborane 6, which was purified by vacuum distillation in 24% yield (Scheme 3). However, ring- closing metathesis (RCM) of 6 with the first-generation Grubbs catalyst proved sluggish. We believe that the intramolecular ring closing to form heterocycle 7 is hindered by the steric bulk of the TIPS group. 127 ~N ....TIPS (CYaPMPhCH)RuCI2 I ---------------------~~B .... Ph CH2CI2, rt 6 NEta hexanesl CH2CI2 -78°C 24% Scheme 3. Fonnation of TIPS-protected 6 and attempted ring-closing metathesis. + ~N ....TIPS H The tert-butyldimethylsilyl (TBS) group is generally intermediate between the TMS and TIPS groups with regard to stability and steric bulk.2o The reaction of allylboron dichloride with TBS-allyl amine furnished aminoborane 8 in 58% yield (Scheme 4).25 Ring-closing metathesis of8 with Grubbs 1st generation catalyst readily provided the six-membered heterocycle, albeit as an isomeric mixture of9 and 9' (60:40 ratio). Catalytic dehydrogenation of this mixture with PdlC produced 1,2-azaborine 10 in 35% yield. The reaction of 10 with LiBHEt3 installed the desired B-H functionality to give 11 in quantitative yield. The direct formation ofthe parent compound 1 from 11 was unsuccessful. The addition oftetrabutylammonium fluoride (TBAF) and other fluoride sources failed to provide 1, yielding either unreacted starting material or undesired side-products resulting from nucleophilic attack at boron. Alternatively, complexation of 1,2-azaborine 11 with tricarbonylchromium(O) trisacetonitrile produced piano-stool adduct 12 in 71 % yield. Subsequent removal of the N-protecting group with a protic fluoride source (HF-pyridine) gave 13 in 76 % yield. Decomplexation of 1 from the Cr(CO)3 group was accomplished using triphenylphosphine. Compound 1 proved difficult to isolate owing to its high volatility. The isolation of 1 in 10% yield (Scheme 4) was realized via the addition of triphenylphosphine to a mixture of isopentane and complex 13, followed by fractional vacuum transfer. While the isolated yield was low, 128 the efficient formation of 1 was demonstrated via IH NMR spectroscopy (84% yield against an internal standard). C....TBS~ ~'CI 9' j 15 mol% Pd/Ccyclohexene, 80°C35% __L_iH_B_E--,t3,-- (~ ....TBS THF, -78 °C ~ B'CI 99% 10 2mol% (CY3Ph(PhCH)RuCI2 CH2CI2, rt 82% PPh3 (WH---......:.....__• I isopentane, rt ~ B'H 10% isolated 84% by 1H NMR 1 Scheme 4. Synthesis of 1,2-dihydro-l,2-azaborine 1. hexanesl CH2CI2 -78°C 58% O ....TBS ~'B-H • (MeCNhCr(COh ~ THF,60°CI Cr(COh 71% 12 jTH~~~~br °C76% ,H (O;B-H I Cr(COh 13 + The technical problem of isolating compound 1 was somewhat overcome by the use of the high-boiling 1,6-dicyanooctane as solvent (Scheme 5). Whereas the isolation of 1 from PPh3 and isopentane required the successive removal of non-volatile solids and the highly volatile isopentane, parent compound 1 was purified in 53% yield via a single vacuum transfer of the product from the reaction mixture. NC(CH2)6CN, rt 53% 13 Scheme 5. Improved conditions for the isolation of 1. 129 The melting point of 1 is -45 DC. In comparison, the melting points ofborazine and benzene are -58 DC and 5 DC, respectively. Compound 1 is stable to silica gel chromatography and is relatively non-polar (Rf= 0.4 with pentane as eluent). Furthennore, I ,2-dihydro-l ,2-azaborine 1 is quite thennally stable; a solution of 1 in CD2Ch showed no appreciable degradation by IH NMR when heated to 60 DC for 5 days. We characterized compound 1 by NMR, UVlVis, and IR spectroscopy, and high- resolution mass spectrometry. The data are consistent with the proposed structure of 1. The IH NMR spectrum of heterocycle 1 is shown in Figure 2. The C-H resonances all appear in the aromatic region and arc characteristic of a 1,2-azaborine. The B-H resonance appears upfield of the other resonances and is split into a broad quartet (ISH = 130 Hz) by the liB atom (S = 3/2). The coupling of the N-H proton with the 14N nucleus (S = I) results in a triplet (IJNH = 57 Hz) that is observed for solutions of 1 in assigned by a combination of COSY and HETCOR NMR techniques (see Appendix B). 6 H 5H~~,H 1 4 H.JyS'H 2 H 3 H4 H6 H5 H3 CDHCI2 H1 H2 I iii I i I Iii' iii I I , Ii. I I 9 ppm 8 7 6 5 4 Figure 2. IH NMR spectrum of 1 in CD2Ch. 130 The UV/Vis absorption spectra of benzene, borazine. and 1,2-dihydro-] .2- azaborine 1 are shovm in Figure 3. The spectrum for compound 1 displays Amax at 269 nm (c = 15632 r'vr1cm-'), with two smaller transitions at 219 nm (c = 8495 M-1cm- l ) and at 205 nm (c = 7459 M-1cm- I ). The absorbance at 269 nm is only slightly red-shifted relative to the a band of benzene (255 nm. c = 977 M-1cm- I ), but absorbs much more strongly than benzene. Benzene's strongest absorption band is located at 208 nm (c = 12380 M-1cm'!). In contrast to benzene and L2-azaborine L the absorption spectrum of borazine sho\-\lS only a very weak band at 203 nm (c = 1299 M-1cm- l ) and negligible absorbance at higher wavelengths. The electronic features of 1 are consistent with a delocalized aromatic motif in marked contrast \-\lith the behavior exhibited by borazine. 1.8 1.6 1.4 1.2 ....,. =! ~ 1 QI v C III 0.8.0(; V) .0 ~ 0.6 0.4 0.2 0 190 210 230 250 )7f) -1 -Benzene -Borazine ,)Qf) 310 Figure 3. Absorption spectra of I, benzene. and borazine. A II substrates are 10.4 M in pentane. 131 Our experimentally determined spectroscopic data are supported by electronic structure calculations (see Appendix B for computational details). The chemical shifts in IH, 13C, llB, and 14N NMR spectroscopy of benzene, compound 1, and borazine were calculated at the density functional theory (DFT) B3LYP/Alhrichs-vtzp level. The excitation energies and oscillator strengths for the prediction of the UVNis spectra of benzene, 1,2-azaborine 1, and borazine were calculated with time dependent DFT (TD- DFT) at the B3LYP/aug-cc-pVDZIIMP2/cc-pVTZ and B3LYP/aug-cc- pVTZIIMP2/cc- pVTZ levels, and with equations of motion CCSD (EOM-CCSD/aug-cc-pVDZIIMP2/cc- pVTZ) level (Appendix B). The IR stretching frequencies of benzene, borazine, and 1 were calculated at the MP2/cc-pVTZ level (Appendix B). Our high-level calculations supported the experimentally determined spectroscopic data for I ,2-dihydro-1 ,2- azaborine 1 (see Appendix B for full characterization of 1). While benzene is considered the quintessential aromatic molecule, the aromaticity of borazine has remained a topic of discussion in the 21 5t century.5-7 With regard to 1,2-dihydro-I,2-azaborine 1, Ashe and co-workers showed that 1,2-azaborines readily undergo electrophilic aromatic substitution reactions.26 Abbey et al. have provided crystallographic evidence of bond delocalization in 1,2-azaborines.27 To complete the analysis, we have directly compared the magnetic and energetic data for I ,2-dihydro-1 ,2-azaborine 1 along with the corresponding data for benzene and borazine. Experimentally, the N-H and B-H chemical shifts of 1 are significantly downfield shifted compared to the corresponding signals for borazine (Table 2, entries I and 2). The nucleus-independent chemical shift (NICS)28 values for benzene, 1,2-dihydro-I,2- 132 azaborine 1, and borazine indicate a trend of decreasing aromaticity going from benzene to borazine. The experimentally observed and computed chemical shifts are consistent with 1,2-dihydro-1 ,2-azaborine 1 possessing substantial aromatic character. We have also predicted the resonance stabilization energy (RSEi9 of 1,2-dihydro-1 ,2-azaborine 1 to be 21 kcal mor l (Table 2, entry 5). This value was derived computationally from the reaction schemes illustrated in Schemes 6 (see Appendix B for full computational details). The RSE of 1 appears to be approximately 13 kcal mor l less than benzene (34 kcal mor l ). Furthermore, the heat of formation has been accurately calculated for benzene and borazine.30,31 The same methods were used to calculate the heat of formation of 1 (Table 2, entry 6). Thus, 1,2-dihydro-1 ,2-azaborine 1 appears to meet all four major criteria of aromaticity. Table 1. Magnetic and Energetic Data for Benzene, 1, and Borazine." 1 6N-H 2 6B-H 3 NICS (0) [-8.76] 4 NICS (1) [-10.39] 5 RSE (kcal mor l ) [34.1] 6 ilHf(298) (kcal morl) [20.5] Entry o 8.44,6 [7.8] 4.9,b [5.4] [-5.62] [-7.27] [21 (±2)] [3.0] 5.63,6 [5.3] 4.4,b [5.0] [-2.02] [-3.01] [10.0t [-119.0] " Numbers in brackets are calculated values. b Experimentally determined lH NMR chemical shifts in CD2C}z. C Value taken from reference 5 based on a different reaction scheme. C~,H~ B"H o ilH = +12.1 kcal mol-1 .. o 133 (~,H O~ ilH = +13.4 kcal mol-1 .. C~,H 0.,-B"H /./ ~ B"H /./ Scheme 6. Reaction schemes for the calculation ofRSE in 1 versus benzene. 1,2-Dihydro-l,2-azaborine I displays unique molecular features relative to its organic counterpart, benzene. Therefore we explored the reactivity of I resulting from substitution by the B-N bond pair. In particular, we were interested in determining whether the N-H proton is protic and the B-H hydrogen is hydridic. The N-H functionality in I undergoes a deuterium exchange in CD30D (Scheme 7). The disappearance of the N-H resonance in the 1H NMR spectrum of I was monitored over the course of approximately 24 h, from which it was determined that the rate constant for exchange in CD30D was kHD = 7(±2) x 10-7 M-1s-1. The B-H group is commonly hydridic in character. With regard to boron heterocycles, Fu and co-workers demonstrated the reduction of aldehydes to alcohols using l-H-boratabenzene.32 However, no reaction between I and benzaldehyde occurred over the course of several days at 60°C (Scheme 8). The complete consumption of benzaldehyde with borazine was observed within 24 h, furnishing reduced benzaldehyde derivatives including dibenzylamine and tribenzylamine. The relatively unreactive nature of lIed us to speculate that the hybrid heterocycle 1 more closely resembles benzene than borazine. 134 (~,H CD30D. (~,D~ B'H ~ B'H Scheme 7. HID exchange in I,2-dihydro-l ,2-azaborine. ( N,H PhCHO I • no reaction ~ B'H 60 °C, 6 days Scheme 8. Exploration of aldehyde reduction using I,2-dihydro-l ,2-azaborine. Although we were unable to detennine the crystal structure of 1, we were able to obtain the stntcture of its chromium(O) tricarbonyl adduct 13. Selected structural parameters for complex 13 are provided in Figure 4 (left). A direct comparison of the features of 13 with the known benzene-Cr(CO)3 piano-stool complex 1433 (Figure 4, right) indicates overall that the binding geometry of the 1,2-dihydro-l ,2-azaborine ring in 13 is quite similar to that of the benzene ligand in 14. The planar 1,2-azaborine ring of 13 is coordinated in an r(fashion to chromium and closely resembles the binding geometry in 14. Accordingly, the Cr-CO and C",O distances are remarkably similar in 13 and 14, indicating that the coordination behavior of 1,2-dihydro-l ,2-azaborine 1 is quite similar to benzene. This is further supported by the nearly identical carbonyl stretching frequencies of 13 (v(CO) = 1898, 1975 em-I) and 14 (v(CO) = 1892, 1972 cm- 1) measured by IR spectroscopy. The binding energy of the 1,2-azaborine ring to the Cr(CO)3 fragment in 13 was calculated at the DFT B3LYP/DZVPZ level to be -54.4 kcal mor l (see Appendix B), which was virtually identical to the benzene derivative (- 54.9 kcal mor\ In contrast, the binding energy ofborazine was calculated to be significantly weaker (-42.7 kcal mor l ). 1.393(3)( i. 1.492(4) --- ----...... c-c = 1.40-1.42 A 135 (C0) I 1.8YC 1 r'"",,~;844 l.15~ 1.848 C 1.1 58O~ C ~O 111 1.152 o 01 "(2) ~ 1.843(2) 03 -1.421(3) / ~37~ I I 1.845(2)/ 1.152(3) ./) 02 14 13 Figure 4. ORTEP illustration (at the 35% probability level) of 13 in direct comparison with the known benzene chromium(O) tricarbonyl complex 14. Electronic structure calculations of compound 1 at the B3LYP/DZVP2 level show that, in contrast to benzene and borazine, the HOMO of 1,2-azaborine is not degenerate. The HOMO-LUMO gap in 1 (5.32 eV) is smaller than those for benzene (6.55 eV) and borazine (7.91 cV). This trend is consistent with the electronic spectra (Figure 3) and with previous calculations.34-35 The orbital diagram of the HOMO of 1 is shown in Figure 5(A). We also detcnnined the charge distribution of 1 in the form of an electrostatic potential (ESP) surface (Figure 5(B)). The calculated electronic structure reveals substantial electron density at the 3 and 5 positions of the 1,2-azaborine ring. This is consistent with the experimental observations made by Ashe, in which eiedrophiiil: arumatic substitutions occur exciusiveiy at the 3 and 5 positions of the heterocycle.26 FUlthennore, the ESP diagram shows a positive electrostatic potential 136 (blue color) at the N-H group, which correlates well with the observed HID exchangc in heterocycle 1. protic (S)©N ... H0, B, H (3) Figure S. A) HOMO of I,2-dihydro-l ,2-azaborine. B) ESP map of I,2-dihydro-l ,2-azaborine at the 0.002 electron a.u,·) density iso-contour level (-13.6 to 39.9 kcal marl). 3.4. Microwave Spectroscopy of 1,2-Dihydro-l,2-azaborine Microwave spectroscopy has been an accurate method for the determination of molecular structure in the gas phase. As we were unable to determine the X-ray crystal structure of 1,2-dihydro-1 ,2-azaborine 1, we were interested in elucidating the structural features of 1 via microwavc spectroscopy. The microwave spectra for compounds of boron and nitrogen have been reported.36-38 While the lack of a permanent molecular dipole in borazinc precludes its study by microwave spectroscopy, the asymmetry in the 1,2-azaborine heterocycle presents an opportunity to collect the microwave spectrum of 1. In collaboration with the Kukolich group, we have perfolmed microwave spectroscopy on 1,2-dihydro-1 ,2-azaborine 1.39 The complicated microwave spectrum of heterocycle 1 was analyzed using highly accurate modeling techniques (see Appendix B), which yielded valuable infonnation rcgarding structure and electron distribution. 137 1,2-Dihydro-1,2-azaborine was determined to be completely planar in the gas phase (see Appendix B), consistent with the X-ray crystal structures of the numerous derivatives discussed in Chapter II. Furthermore, several of the intra-ring bond lengths have been determined and are presented in Figure 6. The B-N bond length of 1.45(3) A is comparable to the values obtained in the solid-state for related derivatives. Similarly, the B-C and N-C bond lengths of 1.51(1) and 1.37(3) A, respectively, are close to the bond lengths observed in the X-ray crystal structures of other 1,2-azaborines. The intra- ring bond angles of 1 are presented in Figure 6 and do not deviate greatly (within error limits) from 1200 • It is worth noting that the pand y angles include error limits as these were the only angles completely determined using modeling techniques. The N-H bond length of 1.02 A is short relative to the B-H bond (1.19-1.21 A), however more experiments would be required for the highly accurate determination of these bond lengths. The dipole moment of 1 was calculated to be 2 D (Figure 6), pointing from the C6 position (most positive) toward the C3 position (most negative). The microwave spectrum of 1 also permitted an analysis of the pz-electron occupancy at boron and nitrogen. It was determined that the valence pz-electron occupation of boron is 0.3 electrons versus 1.3-1.5 electrons at the nitrogen position, indicating a partial overlap of the J't-system with boron's pz orbital. a =1190 ~ =115(3t y =123(3t[) =1200 138 ~b1'37(N3) /HJ ~ 1.022 0t ~ 11.45(3)~(fB~19-1.211.51(1) H Figure 6. Geometric and electronic features of 1 via gas-phase microwave spectroscopy. Carbon-carbon double bonds have been omitted for clarity. 3.5. 1,2-Azaborine Protein Binding The element boron has received little attention in biomedical applications compared to its main group neighbors, carbon, nitrogen, and oxygen. The relative insignificance of boron to living systems may be responsible for the scarcity of boron- containing biomolecules.4o,41 Nevertheless, boron has several useful elemental and chemical features that include nuclear spin, large cross section for neutron capture, and Lewis acidity. The incorporation of boron in biologically-relevant molecules could provide opportunities in marker technologies,42 pharmacological agents,43 or in cancer therapy.44 1,2-Azaborines may serve as biological agents due to their structural and electronic similarity to the biologically prevalent phenyl ring. Therefore, we were interested in probing the ability of the 1,2-azaborine ring to mimic the phenyl system in a biological context. Benzene and ethylbenzene have recently been shown to selectively bind an engineered hydrophobic pocket ofT4lysozyme.45 The L99A mutant ofT4lysozyme creates a non-polar, disc-shaped cavity which is well-suited to bind aromatic substrates. Though internalized within the protein scaffold, aromatic groups readily bind to this pocket. Modified T4lysozyme therefore appeared to be a suitable candidate for a 'proof 139 of principle' binding study with 1,2-dihydro-I,2-azaborine 1 and other derivatives (i. e. 1518 in Figure 7) as a test ofthe biomimetic capabilities ofthis heterocyclic motif. (NI~H VS.~ B'H 1,2-Dihydro- 1,2-azaborine 1 o Benzene ~Et o Ethylbenzene VS.(~~Et~ B'H N-Ethyl- 1,2-azaborine 15 1,2-Dihydro-l,2-azaborine 1, N-ethyl-l,2-azaborine 15, and carbon analogs.Figure 7. Our collaborators in the Matthews group prepared crystals ofL99A T4 lysozyme, which were transferred to an inert atmosphere glovebox. The crystals were soaked in a degassed, buffered solution (2.2 M sodium/potassium phosphate, pH 6.9,50 mM 2-mercaptoethanol, 50 mM hydroxyethyldisulfide), whereupon a few drops of 1,2- dihydro-1,2-azaborine 1 or N-ethyI1,2-azaborine 15 were added to the vessel containing the protein crystals. The sample was quickly cooled to 277 K and stored under inert atmosphere for three days. Diffraction data (see Appendix B) for these samples were then collected at 100 K to 1.25 A resolution. The diffraction data clearly indicated that the parent heterocycle 1 as well as the N-ethyl derivative 15 bound the hydrophobic pocket ofL99A T4lysozyme.46 The binding ofN-ethyl 1,2-azaborine 15 was found to be quite similar to ethylbenzene (Figure 8). Furthermore, 15 binds to the hydrophobic pocket in essentially 100% occupancy, whereas ethylbenzene binds in approximately 60% occupancy. Compound 140 15 and its carbon analog both bind in two alternative geometries; the electron density maps indicate that the aromatic rings are present in opposing ring-flipped confonnations. No close contacts were observed between 15 and the protein scaffold, indicating 1,2- azaborine is a non-polar surrogate for the phenyl ring. b Met102 . a I Figure 8. Difference maps (blue) for the binding of a) 15 and b) ethyl benzene in the T4 lysozyme L99A cavity. The maps are contoured at 3 a ancl 2 a for 15 and ethylbenzene, respectively, at a resolution of 1.25 A. Thc nitrogen atom on the I,2-azaborine ring of 15 is colorcd blue and the boron atom is colored orange. The sites for the boron atoms could not be specified unambiguously (see text). In contrast to ethyl-substituted 15, parent 1,2-azaborine 1 contains an exchangeable N-H moiety and is more polar than benzene, and therefore might reasonably be expected to bind in a very different manner to L99A T4 lysozyme. Furthermore, it has been shown that polar ligands such as pyridine, phenol, and aniline do not bind significantly to the L99A cavity. Despite this, heterocycle 1 bound the hydrophobic pocket ofL99A T4 lysozyme in virtually 100% occupancy and closely resembled the binding of benzene (Figure 9). The binding of heterocycle 1 was again found to occur in two ring-flipped conformations. The absence of any short contacts with or significant changes to the protein scaffold suggests that I,2-dihydro-l ,2- 141 azaborine 1 is a reasonable mimic for benzene. It is of note that this represents the first crystallographic characterization of the parent heterocycle 1. .. Met102 b.. Met102 a Figure 9. Oi fference maps (blue) for the binding of a) 1 and b) benzene in the T4 lysozyme L99A cavity. The maps are contoured althe 3 a level. The nitrogen atom on the I ,2-azaborine ring of 1 is colored blue and the boron atom is colored orange. 3.6. Conclusion In summaty, we prepared 1,2-dihydro-l,2-azaborine 1, a hybrid organic/inorganic benzene that had been elusive until now. The structural, spectroscopic, and chemical data presented in this work were fully supported by high- level calculations, and indicated that 1,2-dihydro-l ,2-azaborine is a stable aromatic molecule with features that are distinct from its "organic" and "inorganic" counterparts. The synthesis and characterization of the parent compound of this family of heterocycles fills an important gap in the study of boron-nitrogen heterocycles and aromaticity. The properties of 1,2-dihydro-l ,2-azaborine make it an attractive target for materials applications. Furthermore, while the application of 1,2-azaborines to biomedical 142 research remains unexplored, we have demonstrated the potential of 1,2-azaborines as mimics of the important phenyl motif. 3.7. Bridge to Chapter IV Chapter IV discusses the synthesis and characterization of conjugated scaffolds incorporating the 1,2-azaborine motif. In a similar route employed toward the synthesis of 1,2-dihydro-1,2-azaborine, BN analogs of diphenylacetylene are produced from a versatile 1,2-azaborine intermediate. The optoelectronic properties of these compounds are discussed in relation to their carbon analogs. The second section of Chapter IV discusses the synthesis of larger diyne scaffolds containing a central 1,2-azaborine core. These derivatives are generated via the unprecedented cross-coupling reactivity of C3- brominated 1,2-azaborines with phenylacetylenes. The consequences of asymmetrically substituting electron-donating and electron-withdrawing groups are explored with respect to optoelectronic properties. 143 CHAPTER IV 1,2-DIHYDRO-l,2-AZABORINE IN CONJUGATED PHENYLACETYLENICSCAFFOLDS 4.1. General Overview This chapter discusses the synthesis and characterization of phenylacetylene derivatives containing the 1,2-azaborine ring. This chapter includes unpublished co- authored material with Jed Volvolic, Dan Chase, and Dr. Lev Zakharov. Some compound preparation was performed by Jed Volvovic and Dan Chase, and X-ray crystallographic data was collected and analyzed by Dr. Lev Zakharov. Otherwise all experimental work was performed by me. The co-authored excerpt as presented here was written entirely by me. Professor Shih-Yuan Liu has provided editorial assistance and scientific guidance for all material presented in this chapter. 4.2. Introduction Conjugated organic materials are of great interest in areas such as light-emitting diodes,! photovoltaic devices,2 and non-linear optical materials? The incorporation of sp2-hybridized boron into small molecule4 and polymeric5 structures has become a key strategy in the design ofn-conjugated materials. Recent pioneering work in the 144 synthesis of aromatic boron heterocycles has provided insight into the fundamental consequences of boron substitution.6-9 Many of these compounds display unique photophysical properties. Recent work has demonstrated that the replacement of C=C units in polycyclic aromatic hydrocarbons with isoelectronic B-N bond pairs imparts favorable photophysical properties while maintaining significant compound stability. 10.1 I The photophysics of monocyclic derivatives of I,2-dihydro-1 ,2-azaborine, isoelectronic with the ubiquitous phenyl ring, have received much less attention. However, the resurgence in the chemistry of I,2-dihydro-l ,2-azaborine (hereafter referred to as 1,2- azaborinc)12-15 has led us to consider the integration of 1,2-azaborine units in conjugated materials. We have chosen diphenylacetylene (tolan) as an attractive target for conjugated materials containing the B-N bond pair (Figure 1). The photophysics of diphenylacetylenc arc well documented. 16 Diphenylacetylene serves as an important building block in material science l ? and is the fundamental sub-unit in the structure of the carbon allotrope graphyne. 18 An extension of the synthetic methods described in Chapters II and III could provide tolan derivatives containing the I,2-azaborinc ring (e. g., 1 and 2 in Figure I). The photophysical consequences of substituting multiple phenylacetylene groups at various positions on the I,2-azaborine ring are also of interest. Diphenylac:p.tylene (Tolan) BN Tolan 1 Bis B!,j To!an 2 Figure I. Derivatives of tolan containing the I,2-azaborinc ring. 145 4.3. Synthesis of BN Tolan Derivatives The synthesis of BN tolan 1 is described in Scheme 1. Nucleophilic substitution ofB-Cl azaborine 3 (see Chapter III, Scheme 4) with phenylethynylmagnesium bromide furnished TBS-protected BN tolan 4 in 76% isolated yield. Attempts to selectively remove the N-silyl group of 4 were unsuccessful. The addition oftetrabutylammonium fluoride (TBAF) to 4 provided 1 in 15% isolated yield, however the competitive nucleophilic attack at the boron position led to the formation of undesired side-products. As in our previous isolation of the parent 1,2-dihydro-1 ,2-azaborine, 15 complexation with chromium(O) provided an alternate route to BN tolan 1. The reaction of4 with (MeCN)3Cr(CO)3 gave piano-stool complex 5 in 91% yield. Deprotection ofthe N-TBS group with HF-pyridine afforded the chromium tricarbonyl complex 6 in 85% yield. Simple dissolution of 6 in MeCN, followed by chromatographic purification gave 1 in good yield. TSS,CS-CI 3 SrMg Ph THF, -78°C 76% ,TSS0- Ph 4 H, 0--==-0 1 (MeCNhCr(COh THF, 25°C 91% MeCN, 25°C 91% N'·.TSS , TBS 8 j(MeCNhcr(COhTHF, 25°C N/TBS (CU;B--==--B:P> I TBS; Cr(COh 9 2 Scheme 2. Synthesis ofbis BN tolan 2. 147 We obtained the X-ray crystal structures of 1 and 2. The structure of 1 is illustrated in Figure 2, which confi rms the structural assignment of the BN tolan analog. The structure of 1 is nearly co-planar through the alkyne-bridged rings with the 1,2- azaborine and phenyl rings twisted less than 3° relative to each other. The structure is linear through the B-C=C-C unit and the exocyclic B(l )-C(5) bond is slightly longer (1.545(5) A) than the corresponding C(7)-C(6) bond (1.436(5) A) due to the increased size of the boron atom relative to carbon. The intra-ring 1,2-azaborine bond distances in 1 are similar to those observed in the N-benzyl derivative presented in Chapter II, Figure 17. The boron atom appears completely planar, indicating Sp2 geometry. Interestingly, the exocyclic alkyne substituent is bent away from the C(4) atom (LC(4)-B(l)-C(5) = 128.3(3)°) toward the nitrogen position (LN(l )-B(l )-C(5) = 116.6(3)°). The intra-ring angles (LN(l)-B(l)-C(4) = 114.9(3)°, LC(l)-N(l)-B(l) = 123.5(3)°) very closely resemble those determined for the parent 1,2-azaborine via microwave spectroscopy (Chapter Ill, Figure 6).20 The full crystallographic data for 1 are presented in Appendix c. Figure 2. ORTEP illustration of 1, with thermal ellipsoids drawn at the 35% probability level. The solid-state structure of 2 is presented in Figure 3. The structure is co-planar and the B-C=C-B axis is linear, indicating Jt-overlap throughout the bicycle. Surprisingly, the nitrogen atoms of the I ,2-azaborine rings are in a cis conformation 148 about the B-C=C-B axis. This is in contrast to compound 8, which preferred a trans conformation (see Appendix C for crystallographic data of 8). In the crystal packing of 8 there appears to be a short contact betwecn the N-H proton and alkyne bridge of adjacent molecules (Figure 4, left: R···Jt = 2.55 A, LN-H-Jt = 159°). Hydrogen- bonding between an N-H donor and alkync acceptor is rarc. 2J -22 The formally isoelectronic relationship between I ,2-azaborine and the phenyl ring lead us to speculate that the short N-R···Jt interaction could potentially be a mimic ofC-H····Jt, for which there are numerous examples. 21 Solid-state C-R···Jt interactions are generally longer than N-H····Jt and deviate more greatly from 180°. The interactions in 2 are intennediary betwccn typical C-H····Jt and N-H····Jt hydrogen bonds. Thin-film infra-red spectroscopy also indicates modest wcakening of the N-H bond in 2 (3370 em-I) relative to the parent compound, I ,2-dihydro-1 ,2-azaborine (3800 cm- I)15 and other reported (N-H)-J ,2- azaborines. 23 We also observe Jt-stacking in the crystal structure of 2 (Figure 4, right). The separation between adjacent molecules of 2 is 3.5 A and is offset such that the boron atom of one molecule is aligned with C(4) of its dimeric partncr. The boron atom of 2 is clectrophilic while DFT calculations have shown that the carbon attached to boron has thc largest negativc potential on the I ,2-azaborine ring. 15,2o Therefore, the offset Jt- stacking in 2 could result from a minimized dipole in the solid-state. ,I, / , "!'"--{" l I I l : l I Figure 3. ORTEP illustration of2, with thermal ellipsoids drawn at the 35% probability level. 149 I , I ,I. I )~' I' ; 3,22 --I ..,.-: .~":l'j)\~ t" \ .. " -l.... ~'--.,- ....-'~ -r- - - .•. NIA -----I{ !-.--_~."",,:-- 3.22 . - - , 255 N2A l ( ,I ,2.55 / N) .."/a " "-J I Figure 4. ORTEP illustrations, with thermal ellipsoids drawn at the 30% probability level, of N-H ....Jt (len) and IT-stacking (right) interactions in BN tolan 2. All distances are in A. The absorption spectra of 1,2, and tolan in THF are presented in Figure 5. The absorption spectra of 1 and 2 display similar features. Both compounds have a strong absorption at 299 nm. The weaker absorption in 1 at 268 nm is blue-shifted to 256 nm in 2. The absorption band at 299 nm is broadened significantly for the BN tolan derivatives relative to tolan. As a result, 1 and 2 absorb out to a wavelength of 325 nm. The intensity in the 299 nm band is greater in 2 than 1 (58789 and 35072 M'lcm'l respectively), which correlates with the number of 1,2-azaborine units in each molecule. Though broadened, some fine structure is observed in the absorption spectra of 1 and 2; both compounds display an absorption "shoulder" band at about 320 nm. 150 340320300240 10000 1 o I 220 70000 _I - 1 60000 -2 -Tolan 50000 -....E 40000 u .... ~ --- 30000 ~ B~Br ~Ph~NI_R> Ph 12 Scheme 3. Retrosynthetic analysis of 12. Our synthetic route to 12 is presented in Scheme 4. The bromination ofB-Cl 1,2-azaborine 3 proceeded smoothly to provide 13 in good yield after vacuum distillation. Nucleophilic substitution of 13 with phenylethynylmagnesium bromide provided alkyne-substituted 14 in 76% yield. The lynchpin of our synthesis was the cross-coupling ofbrominated 14 with phenylacetylene, which was sluggish using a standard Sonogashira cross-coupling protocol (method A in Scheme 4).31 Nevertheless, the observation of diyne 15 by 1H NMR led us to consider the more reactive catalyst system developed specifically for the cross-coupling of aryl bromides.32 Gratifyingly, the coupling of 14 with phenylacetylene under these conditions (method B in Scheme 4) produced 15 in 85% isolated yield. We were unable to directly cleave the TBS protecting group from diyne 15. Instead, the complexation of 15 with tricarbonylchromium(O) trisacetonitrile provided piano-stool complex 16 in 43% yield. The N-TBS group of 16 was cleaved with HF-pyridine. The reaction mixture was directly added to MeCN, whereupon diyne 12 was isolated via silica gel chromatography, albeit in low yield. 154 (~"TBS Br2 ~~/TBS BrMg _ Ph • ~~/TBS ~ B'CI CH2CI2, -20°C ~ B'CI THF, 25°C ~ B 61% 76% ~ 3 Br Br Ph 13 14IA' 25%' B: 85%b 1~_H 1) HF-pyr, 1 fTBSTHF, -20°C ~B~ 2) MeCN, 25°C (MeCNhCr(COh ~B~~ 19% (2 steps) THF, 25°C ~II Ph 43% II Ph Ph 16 Ph 12 15 A. 5 equiv. H == Ph, 10 mol% Pd(CI)2(PPhs)2, 20 mol%Cul, THFINEts, 25°C a 1H NMR integration versus 14. Scheme 4. Synthesis of diyne 12. B. 1.3 equiv. H Ph, 3 mol% Pd(CIMPhCNh, 3 mol% Cui, 6 mol% P(IBuh, THF/NEts, 25°C b Isolated yield. We have characterized 12 by NMR, JR, UV-Vis, and fluorescence spectroscopy, as well as high resolution mass spectrometry (HRMS), all of which are consistent with the assigned structure. The structure of 12 has been unambiguously determined by X- ray crystallography, though disorder in the structure prevents the accurate determination of bond parameters. We have also obtained the X-ray crystal structure of chromium complex 16; crystallographic data for 16 are given in Appendix C. The absorption and emission spectra of 12 are shown in Figure 9. The absorption spectrum (blue) of 12 shows a broad absorption maximum at 328 nm (£ = 23316 M-1cm- 1). By comparison, the absorption spectrum of 1,2-bis(phenylethynyl)benzene in benzene shows an absorption at approximately 320 nm. Therefore, the HOMO-LUMO transition appears quite similar in 12 and the carbon-based analog. A second absorption 155 at higher energy is seen in the absorption spectrum of I2 (259 nl11, E = 23913 M-1cm- I ). The fluorescence spectrum of heterocycle I2 (Figure 9. red trace) displays a strong peak at 378 nm (PL = 0.35), which varies minimally from a related carbon analog with respect to the ApL and PL values?8 The emission maximum of 18 is bathochromically shifted to 552 nm, but 161 is much vieaker ((1)1'1 = 0.04) than the corresponding emission in 17. A second emission peak is evident in the emission of 18: this peak becomes more prominent when 18 is excited at 339 nm. As a result of this dual emission. compound 18 emits visible white light in THF. -12 ::c ., .~ "iii E o z ., u c ro .n o '".n oJ: o 250 275 300 325 350 375 400 425 450 Wavelength (nm) Figure It. Normalized absorption spectra for 12. 17. and 18. All substrates are 10-5 M in THF. 1.1 1 0.1 !} -12 -17 340 380 420 460 500 540 580 620 660 700 Wavelength (nm) Figure 12. Normalized emission spectra for 12,17, and 18. All substrates are 10-' Min n-IF. ----- ---- 162 To further understand the photophysical properties ofdonor-acceptor compounds 17 and 18, we have constructed the phenylethynyl 1,2-azaborines 26 and 27 shown in Figure 13. Boron-substituted 26 is a sub-unit ofdiyne 17, while 27 can be considered a sub-unit of 18. The photophysical examination of26 and 27 could provide insight into the conjugation pathways in the corresponding diyne structures. 26 27 Figure 13. 1,2-Azaborines 26 and 27 are fundamental sub-units of diyne scaffolds 17 and 18. The synthesis of boron-substituted alkynes 26 and 27 is shown in Scheme 8. The addition of a donor- or acceptor-functionalized alkynyl Grignard to 1,2-azaborine 3 generates the TBS-protected BN tolans 28 and 29, respectively. Reaction of28 and 29 with tricarbonylchromium(O) trisacetonitrile forms the Y1 6 complexes 30 (R = NBu2) and 31 (R = CN). Cleavage of the silyl group with HF-pyridine gives the isolable complexes 32 (R = NBu2) and 33 (R = CN). Decomplexation of the 1,2-azaborine ligands in 32 and 33 gives the desired BN tolans 26 and 27, respectively. The absorption and emission properties for 26 and 27 are summarized in Table 1, and diynes 17 and 18 are included for comparison. The data indicate that conjugation extends throughout the diyne scaffold of 17 and 18. The observed photophysical properties of the donor-acceptor diynes are not a result of one of the arms acting as the sole fluorophore; an intramolecular charge transfer process in likely taking place in both diynes. The emission energies for 17 and its sub-unit 26 are higher than those of 18 and 163 its sub-unit 27, respectively, by approximately 50 run. A trend is also apparent in the quantum yields, in which 17 and 26 have much higher quantum yields than 18 and 27. It is clear that the phenylethynyl substituent at the boron position plays a significant role in the observed optoelectronic properties of these compounds. ,TBS CB-CI 3 BrMg <}-R THF, 25°C ,TBS CB <}-R 28 R =NBu2 (78%) 29 R =CN (64%) j(MeCNhcr(COhTHF, 25°C N~H -R I Cr(COh 32 R =NBu2 (57%) 33 R =CI\J (53%)IMeCN, 25°C HF-pyr • THF, -20°C N .....TBS -2sigma(I)] R indices (all data) Absolute structure parameter Largest diff. peak and hole -16<=h<=12, -7<=k<=7 , -24<=1<=24 9061 3243 [ROnt) = 0.0425] 99.8 % Semi-empirical from equivalents 0.9544 and 0.8400 Full-matrix least-squares on F2 3243/1/191 1.003 R1 = 0.0390, wR2 = 0.0778 R1 = 0.0538, wR2 = 0.0864 0.20(3) 0.301 and -0.206 e.A-3 203 Table 8. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2x 103) for liu12a. U(eq) is defined as one third of the trace of the orthogonalized uij tensor. X y Z U(eq) Cr(1) 6657(1) 7430(1) 9776(1) 26(1) 0(1) 7486(2) 3932(4) 8775(1) 55(1) 0(2) 4623(2) 4941(4) 9940(1) 45(1) 0(3) 5789(2) 11017(4) 10726(1) 48(1) 0(4) 8662(2) 10056(4) 9693(2) 63(1) 0(5) 7561(2) 4899(4) 10990(1) 52(1) N(1) 5758(2) 10066(4) 8506(1) 35(1) N(2) 5727(2) 11203(4) 7264(1) 30(1) B(I) 5390(3) 11603(6) 7950(2) 31(1) C(1) 7175(3) 5237(5) 9153(2) 33(1) C(2) 5388(2) 5846(5) 9869(2) 30(1) C(3) 6121(3) 9656(5) 10371(2) 32(1) C(4) 7910(2) 9078(5) 9713(2) 38(1) C(5) 7216(3) 5855(6) 10530(2) 34(1) C(6) 6086(2) 9084(5) 8972(2) 29(1) C(7) 4700(3) 13536(6) 8088(2) 41(1) C(8) 4463(3) 14870(6) 7534(2) 47(1) C(9) 4837(3) 14417(6) 6867(2) 43(1) C(IO) 5449(3) 12648(5) 6749(2) 36(1) C(11) 6445(3) 9368(6) 7074(2) 40(1) C(12) 7559(3) 10065(6) 7169(2) 45(1) Table 9. Bond lengths [A] and angles [0] for liul2a. Cr(l)-C(5) Cr(1)-C(3) Cr(I)-C(I) Cr(I)-C(4) Cr(I)-C(2) Cr(I)-C(6) 0(1)-C(1) 1.875(4) 1.889(4) 1.900(4) 1.904(3) 1.908(3) 1.981(3) 1.141(4) 0(2)-C(2) 0(3)-C(3) 0(4)-C(4) 0(5)-C(5) N(1)-C(6) N(1)-B(1) N(2)-C(10) N(2)-B(1) N(2)-C(11) B(1)-C(7) C(7)-C(8) C(7)-H(7A) C(8)-C(9) C(8)-H(8A) C(9)-C(10) C(9)-H(9A) C(1 O)-H(1 OA) C(11)-C(12) C(11)-H(11A) C(11)-H(11B) C(12)-H(12A) C(12)-H(12B) C(12)-H(12C) C(5)-Cr(1)-C(3) C(5)-Cr(1 )-C( 1) C(3)-Cr(1)-C(1) C(5)-Cr(1)-C(4) C(3)-Cr(1 )-C(4) C(1)-Cr(1)-C(4) C(5)-Cr(1 )-C(2) C(3)-Cr(1)-C(2) C(1)-Cr(1 )-C(2) C(4)-Cr(1)-C(2) C(5)-Cr(1 )-C(6) C(3)-Cr(1)-C(6) C(1)-Cr(1 )-C(6) C(4)-Cr( 1)-C(6) C(2)-Cr(1)-C(6) C(6)-N(1)-B(1) C(10)-N(2)-B(1) C(10)-N(2)-C(11) B(1)-N(2)-C(11) N(2)-B(1)-N(1) N(2)-B(1)-C(7) N(1 )-B(1 )-C(7) O( 1)-C(1)-Cr( 1) 0(2)-C(2)-Cr(1) 0(3)-C(3)-Cr( 1) 0(4)-C(4)-Cr(1) 0(5)-C(5)-Cr(l) N(1 )-C(6)-Cr(1 ) C(8)-C(7)-B(1) C(8)-C(7)-H(7A) 1.138(3) 1.147(4) 1.138(3) 1.146(4) 1.153(4) 1.489(4) 1.365(4) 1.412(4) 1.484(4) 1.486(5) 1.368(5) 0.9500 1.399(5) 0.9500 1.342(5) 0.9500 0.9500 1.514(5) 0.9900 0.9900 0.9800 0.9800 0.9800 91.55(15) 90.33(14) 178.11(16) 88.83(16) 89.27(15) 90.92(15) 90.62(14) 88.58(14) 91.24(14) 177.77(17) 179.16(16) 89.07(13) 89.04(14) 90.62(14) 89.95(13) 172.4(3) 119.4(3) 117.0(3) 123.3(3) 117.9(3) 119.0(3) 123.0(3) 179.5(3) 178.1(3) 179.2(3) 178.3(4) 179.7(4) 179.3(3) 116.7(3) 121.6 204 B(1)-C(7)-H(7A) 121.6 C(7)-C(8)-C(9) 121.7(3) C(7)-C(8)-H(8A) 119.2 C(9)-C(8)-H(8A) 119.2 C(10)-C(9)-C(8) 120.9(3) C(10)-C(9)-H(9A) 119.5 C(8)-C(9)-H(9A) 119.5 C(9)-C(10)-N(2) 122.1(3) C(9)-C(10)-H(10A) 118.9 N(2)-C(10)-H(10A) 118.9 N(2)-C(11 )-C(12) 111.4(3) N(2)-C(11)-H(11A) 109.3 C(12)-C(11)-H(11A) 109.3 N(2)-C(11)-H(11B) 109.3 C(12)-C(11)-H(11B) 109.3 H(11A)-C(1l)-H(1lB) 108.0 C(11)-C(12)-H(12A) 109.5 C(11)-C(12)-H(12B) 109.5 H(12A)-C(12)-H(12B) 109.5 C(11)-C(12)-H(12C) 109.5 H(12A)-C(12)-H(12C) 109.5 H(12B)-C(12)-H(12C) 109.5 Symmetry transformations used to generate equivalent atoms: Table 10. Anisotropic displacement parameters (A2x 103)for liu12a. The anisotropic displacement factor exponent takes the form: -2p2[ h2a*2U 11 + ... + 2 h k a* b* U 12 ] Ull U22 U33 U23 U13 U12 Cr(1) 22(1) 25(1) 29(1) 4(1) -2(1) -1(1) 0(1) 49(2) 46(2) 71(2) -16(1) 15(2) -4(1) 0(2) 30(1) 48(1) 56(2) 2(1) 0(1) -11(1) 0(3) 58(2) 38(1) 49(2) -8(1) 0(1) 6(1) 0(4) 34(1) 51(1) 105(2) 14(2) -6(2) -13(1) 0(5) 42(2) 62(2) 52(2) 26(1) -12(1) 5(1) N(1) 31(2) 43(2) 31(1) 5(1) 2(1) 0(1) N(2) 27(2) 32(2) 31(1) 2(1) -3(1) -4(1) B(1) 30(2) 35(2) 29(2) 4(2) -5(2) -3(2) C(1) 26(2) 28(2) 45(2) 4(2) 3(2) -3(2) C(2) 33(2) 29(2) 26(2) 2(1) -5(2) 3(1) C(3) 30(2) 30(2) 35(2) 7(2) -6(2) -2(2) C(4) 30(2) 30(2) 53(2) 8(2) -1(2) -1(1) C(5) 29(2) 35(2) 39(2) 3(2) -3(2) -6(2) C(6) 22(2) 34(2) 31(2) 2(1) 4(2) -1(1) C(7) 36(2) 53(2) 35(2) -4(2) -2(2) 7(2) C(8) 40(2) 40(2) 61(2) 6(2) -11(2) 10(2) C(9) 43(2) 42(2) 44(2) 14(2) -14(2) -10(2) C(10) 36(2) 46(2) 27(2) 7(1) -6(1) -11(2) C(11) 44(2) 34(2) 42(2) -6(2) 5(2) 2(2) C(12) 33(2) 51(2) 52(2) 2(2) 7(2) 5(2) 205 206 Table 11. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2x 103) for liu12a. x y z U(eq) H(7A) 4436 13831 8539 49 H(8A) 4033 16137 7603 57 H(9A) 4655 15374 6493 51 H(lOA) 5697 12393 6291 44 H(llA) 6328 8938 6584 48 H(llB) 6301 8046 7368 48 H(l2A) 8013 8818 7043 68 H(l2B) 7678 10477 7655 68 H(l2C) 7708 11350 6870 68 Table 12. Hydrogen bonds for liu12a [A and 0]. D-H...A d(D-H) d(H...A) d(D...A) «DHA) A.2.5 Supplemental in/ormation/or Chapter II, section 2.5 Compound 13. In a glovebox, a solution of3 (0.600 g, 4.24 mmol in 25 mL benzene) was added dropwise to a stirring suspension of AgOTf (1.31 g, 5.09 mmol in 25 mL benzene). The reaction was stirred at rt for 8 h, whereupon the solvent was removed under reduced pressure. Compound 13 was purified by vacuum distillation (35°C, 100 mTorr) as a clear, colorless liquid (0.639 g, 59%). IH NMR (600 MHz, CD2Ch): 67.76 (br m, 1H), 7.21 (d, 3JHH = 6.3 Hz, 1H), 6.65 (d, 3JHH = 11.4 Hz, 1H), 6.39 (ddd, 3JHH = 11.4,6.3,3.2 Hz, 1H), 3.78 (q, 3JHH = 7.3 Hz, 2H), 1.34 (t, 3JHH = 7.3 Hz, 1H). BC NMR (75 MHz, CD2Ch): 6 148.6, 138.9, 119 (br), 119(q, IJcp=318 Hz), 111.5,46.5, 17.7. llBNMR(192.5 MHz, CD2Ch): 628.0. FTIR (thin film) 3139, 3080,2986,2939,2908,2880, 1870, 1764, 1611, 1528, 1481, 1456, 1444,1413,1351,1209,1153,1112,1060,1006,944,830, 785,768,747,684,618,572, 207 Compound 14a. In a glove box, a solution of 4-phenylpyridine (0.073 g, 0.470 mmol in 1 mL CH2Clz) was added to a stirring solution of 13 (0.100 g, 0.392 mmol in 1 mL CH2Clz). The reaction was stirred for 1 h at rt, whereupon the product was crystallized by cooling the reaction to -20°C for 24 h. The solvent was decanted and the crystallized product was washed with pentane (3 x 5 mL). Residual solvents were removed under reduced pressure to provide 14a as pale-green crystals (0.155 g, 97%). IH NMR (600 MHz, CD2Clz): b 8.82 (d, 3JHH = 6.9 Hz, 2H), 8.44 (d, 3JHH = 6.9 Hz, 2H), 8.02 (dd, 3JHH = 9.8, 6.6 Hz, IH), 7.97 (dd, 3JHH = 8.1 Hz, 4JHH = 1.7 Hz, 2H), 7.68 (m, 3H), 7.55 (d, 3JHH = 6.6, IH), 6.85 (app t, 3JHH = 7.5 Hz, 2H), 3.83 (q, 3JHH = 7.3 HZ,2H), 1.38 (t, 3JHH = 7.3 Hz, 3H). BC NMR (75 MHz, CD2Clz): b 158.1, 149.5, 145.8, 139.6, 134.3, 133.2, 130.5, 128.7, 125.7, 124 (br), 123.6, 115.7,47.7, 18.2. llB NMR (192.5 MHz, CD2Clz): b 31.0. FTIR (thin film) 3220, 3138, 3078, 2915, 1638, 1612, 1513,1488,1474,1442,1412,1377,1349,1292,1233, 1218, 1174, 1151, 1029,833,765, 736,693 em-I. HRMS (EI) calcd for C7H9BN03SF3 (M+) 255.03484, found 255.03528. Compound 14b. In a glove box, a solution oftrimethylphosphine (0.039 g, 0.510 mmol in 1 mL CH2Clz) was added to a stirring solution of 13 (0.100 g, 0.392 mmol in 1 mL CH2Ch). The reaction was stirred for 1 h at rt, whereupon the solvent and residual trimethylphosphine were removed under reduced pressure, providing 14b as a white solid (0.129 g, 99%). IH NMR (600 MHz, CD2Clz): b 7.97 (br, IH), 7.66 (d, 3JHH = 5.4 Hz, IH), 7.11 (d, 3JHH = 10.7 Hz, IH), 6.94 (app t, 3JHH = 6.1 Hz, 2H), 4.06 (q, 3JHH = 7.0 Hz, 2H), 1.99 (d, 2JPH = 12.4 Hz, 9H), 1.51 (t, 3JHH = 7.0 Hz, 3H). BC NMR (125 MHz, CD2Clz): b 146.7, 208 142.0, 130 (br), 121 (q, IJCF = 321 Hz), 118.0,52.6, 19.2, 10.1 (d, IJpc = 45.3 Hz). llB NMR (192.5 MHz, CD2Ch): () 28.7. 3Ip NMR (202 MHz, CD2Ch): () -25.0 (br). FTIR (thin film) 3054, 3008, 2927, 1598, 1526, 1477, 1428, 1410, 1300, 1259, 1226, 1162, 1032,964,872, 758, 673, 639, 573, 517 em-I. Compound 14c. In a glove box, a solution of triphenylphosphine oxide (0.060 g, 0.216 mmol in 3 mL CH2Ch) was added to a stirring solution of 13 (0.050 g, 0.196 mmol in 3 mL CH2Ch). The reaction was stirred for 1 h at rt, whereupon the solvent and was removed under reduced pressure. The white solid was washed with pentane (3 x 3 mL), providing 14c as a white solid (0.093 g, 89%). IH NMR (600 MHz, CD2Ch): () 7.94-7.75 (br, 15H), 7.55 (dd, 3JHH = 10.8,6.8 Hz, 1H), 7.28 (d, 3JHH = 6.4 Hz, 1H), 6.33 (app t, 3JHH = 6.8 Hz, 1H), 5.64 (d, 3JHH = 11.5 Hz), 3.92 (q, 3JHH = 7.3 Hz, 2H), 1.35 (t, 3JHH = 7.3 Hz, 3H). BC NMR (125 MHz, CD2Ch): () 145.1,139.3,134.2,133.2,132.4,129.1,111.3,48.8, 17.6. llBNMR(192.5MHz, CD2Ch): () 28.3. 3Ip NMR (202 MHz, CD2Ch): () 57.3. Compound 14d. In a glove box, a solution of pyridine N-oxide (0.031 g,0.324 mmol in 3 mL CH2Ch) was added to a stirring solution of 13 (0.075 g, 0.294 mmol in 3 mL CH2Ch). The reaction was stirred for 1 h at rt, whereupon the solvent and was removed under reduced pressure. The solid was washed with pentane (3 x 3 mL), providing 14d as light green crystals (0.105 g, 99%). IH NMR (600 MHz, CD2Ch): () 8.97 (dd, 3JHH = 5.9,1.0 Hz, 2H), 8.60 (dt, 3JHH = 7.8,1.2 Hz, 1H), 8.28 (dd, 3JHH = 7.0, 1.7 Hz, 2H), 7.65 (dd, 3JHH = 11.3,6.6 Hz, 1H), 7.26 (d, 3JHH = 6.6 Hz, 1H), 6.31 (app t, 3JHH = 6.6 Hz, 1H), 5.50 (d, 3JHH = 11.0 Hz, 1H), 3.88 209 (q, 3JHI-f = 7.3 Hz, 2H), 1.43 (t, 3JHH = 7.3 Hz, 3H). BC NMR (125 MHz, CD2Ch): 6 149.6, 145.0, 141.9, 139.7, 130.7, 121 (q, IJCF = 320 Hz), 112 (br), 110.4,46.1, 17.5. llB NMR (192.5 MHz, CD2Ch): 631.0. FTIR (thin film) 3117, 3069, 2983,1610,1528,1480, 1444, 1415, 1264, 1224, 1143, 1030,853, 786, 750, 672, 637 em-I. Compound 14e. In a glove box, a solution of dimethylsulfoxide (0.031 g, 0.324 mmol in 3 mL CH2Ch) was added to a stirring solution of 13 (0.075 g, 0.294 mmol in 3 mL CH2Ch). The reaction was stirred for I hat rt, whereupon the solvent and was removed under reduced pressure. The solid was washed with pentane (3 x 3 mL), providing 14d as light green crystals (0.105 g, 99%). IH NMR (600 MHz, CD2Ch): 67.79 (dd, 3JHH = 11.2,6.6 Hz, 1H), 7.20 (d, 3JHH = 6.3 Hz, 1H), 6.49 (d, 3JHH = 11.5 Hz, 1H), 6.34 (app t, 3JHH = 6.6 Hz, 1H), 3.74 (q, 3JHH = 7.3 Hz, 2H), 3.47 (br, 6H), 1.30 (t, 3JHH = 7.3 HZ,3H). BC NMR (125 MHz, CD2Ch): 6 149.5, 139.6, 110.8,45.9,37.1, 17.8. llB NMR (192.5 MHz, CD2Ch): 629.1. FTIR (thin film) 3016, 2927, 1683, 1610, 1525, 1475, 1443, 1413, 1255, 1225, 1157, 1029,988,899, 780, 744, 686, 638, 573, 517 em-I. HRMS (EI) calcd for C9HI6BN04S2F3 (M+) 334.0566, found 334.0550. Compound 14f. In a glove box, a solution of pyridine (0.040 g, 0.506 mmol in 1 mL CH2Ch) was added to a stirring solution of 13 (0.100 g, 0.392 mmol in 1 mL CH2Ch). The reaction was stirred for 1 hat rt, whereupon the solvent and residual pyridine were removed under reduced pressure to provide 14f as a light-yellow solid (0.125 g, 95%). IH NMR (600 MHz, CD2Ch): 6 8.85 (dd, 3JHH = 6.1 Hz, 4JmI = 0.9 Hz, 2H), 8.65 (tt, 3JHH = 7.2 Hz, 4JHH = 0.9 Hz, 1H), 8.25 (dd, 3JHH = 7.2, 6.1 Hz, 2H), 7.98 (dd, 3JHH = 210 11.4,7.0 Hz, IH), 7.55 (d, 3JHH = 6.4 Hz, IH), 6.83 (dt, 3JHH = 7.0, 1.1 Hz, IH), 6.77 (dd, 3JHH = 11.4, 1.1 Hz, IH), 3.72 (q, 3JHH = 7.3 Hz, 2H), 1.30 (t, 3JHH = 7.3 Hz, 3H). BC NMR (75 MHz, CD2Ch): b 149.4, 147.0, 146.0, 139.5, 129.0, 125 (br), 121 (q, IJCF = 321 Hz), 115.7,47.5, 17.9. llB NMR (192.5 MHz, CD2Ch): b 30.9. FTIR (thin film) 3116, 3073,3048,2985,1969,1909,1799,1611,1526,1463, 1412, 1391, 1360,1334,1282, 1226, 1162, 1123, 1081, 1030,988, 784, 758, 698, 685, 638, 599, 573 em-I. Compound 14g. In a glove box, a solution of 4-trifluoromethylpyridine (0.075 g, 0.510 nunol in 1 mL CH2Ch) was added to a stirring solution of 13 (0.100 g, 0.392 nunol in 1 mL CH2Ch). The reaction was stirred for 4 h at rt, whereupon the solvent and residual 4-trifluoromethylpyridine were removed under reduced pressure to give 14g as a bright- yellow solid (0.142 g, 90%). IH NMR (600 MHz, CD2Ch): b 9.10 (d, 3JHH = 5.0 Hz, 2H), 8.27 (br m, 2H), 7.96 (dd, 3JHH = 10.6, 7.4 Hz, IH), 7.48 (d, 3J HH = 7.1, IH), 6.80 (d, 3J HH = 10.6 Hz, IH), 6.75 (br m, IH), 3.77 (q, 3JHH = 7.3 Hz, 2H), 1.33 (t, 3JHH = 7.3 Hz, 3H). l3C NMR (75 MHz, CD2Ch): b 149.5, 148.9, 139.5, 124.3, 122 (br), 120.2, 115.1,47.4, 18.0. liB NMR (192.5 MHz, CD2Ch): b 30.0. FTIR (thin film) 3054, 2987, 2361, 2306, 1653, 1609, 1559, 1521, 1473, 1456, 1321, 1264, 1166, 1081, 1031,896, 740, 639, 574, 518 em-I. Compound 14h. In a glove box, a solution of 4-methylpyridine (0.047 g, 0.510 nunol in 1 mL CH2Ch) was added to a stirring solution of 13 (0.100 g, 0.392 nunol in 1 mL CH2Ch). The reaction was stirred for 1 h at rt, whereupon the solvent and residual 4- methylpyridine were removed under reduced pressure to give 14h as a light-yellow solid (0.130 g, 95%). 211 IH NMR (600 MHz, CD2Ch): () 8.64 (d, 3JHH = 6.2 Hz, 2H), 8.01 (d, 3JHH = 6.2 Hz, 2H), 7.96 (dd, 3JHH = 10.5, 7.1 Hz, IH), 7.54 (d, 3JHH = 7.6, 1H), 6.80 (app t, 3JHH = 6.8 Hz, 1H), 6.75 (d, 3JHH = 10.5 Hz, 1H), 3.72 (q, 3JHH = 7.3 Hz, 2H), 2.72 (s, 3H), 1.30 (t, 3JHH = 7.3 Hz, 3H). l3C NMR (75 MHz, CD2Ch): () 161.2, 149.2, 144.8, 139.5, 129.4, 124 (br), 121 (q, IJCF = 320 Hz), 115.5,47.4,22.7, 17.9. liB NMR (192.5 MHz, CD2Ch): () 30.9. FTIR (thin film) 3112, 3087, 3042, 2976, 2939, 2883, 2309, 1972, 1820, 1707, 1639,1607,1528,1452,1412,1388,1368,1334,1267, 1145, 1086, 1028,989,858,832, 806, 767, 754, 738, 720, 700, 661, 636 em-I. Compound 14i. In a glove box, a solution of 4-(N,N-dimethyl)pyridine (0.057 g, 0.470 mmol in 1 mL CH2Ch) was added to a stirring solution of 13 (0.100 g, 0.392 mmol in 1 mL CH2Ch). The reaction was stirred for 1 h at rt, whereupon the solvent was removed under reduced pressure. The product was washed with EhO (3 x 5 mL) providing 14i as a tan oil which was crystallized by adding a seed crystal of 14h. The resultant tan solid was washed with Et20 (3 x 5 mL) and residual solvent was removed under reduced pressure to provide 14i as an off-white crystalline solid (0.144 g, 98%). IH NMR (600 MHz, CD2Ch): () 7.98 (d, 3JHH = 6.9 Hz, 2H), 7.71 (d, 3JHH = 6.6 Hz, 1H), 7.28 (d, 3JHH = 6.6 Hz, 1B), 6.90 (d, 3JHH = 6.9 Hz, 2H), 6.48 (d, 3JHH = 13.0 Hz), 6.41 (m, 1B), 3.67 (q, 3JHH = 7.3 Hz, 2H), 3.23 (s, 6H), 1.22 (t, 3JHH = 7.3 Hz, 3H). l3C NMR (125 MHz, CD2Ch): () 156.8, 145.0, 143.7, 138.9, 124 (br), 121 (q, IJCF = 321 Hz), 110.2, 108.4,46.7,40.4, 17.6. liB NMR (192.5 MHz, CD2Ch): () 26.7. FTIR (thin film) 3230,3094,2976,2935,2873,2822,2625,2441,2296, 1975, 1899, 1796, 1644, 1611, 1564,1525,1483,1445,1383,1342,1266,1151, 1066, 1031,948,917,822,754,735, 212 656,637,573,517 cm- I . ( ) (]I /'I'(,) --: ' 1(li) \ Figure 10. ORTEP illustration of 14a, with ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of 14a suitable for X-ray diffraction were obtained by cooling a CH2Cb solution of 14a to -20 °C for 24 h. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2. All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package 213 (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for CIsHISBF3N203S are given in the following tables. Table 13. Crystal data and structure refinement for 14a (liu9). a= 90°. /3= 100.9400(10t· y = 90°. Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 27.00° Absorption correction Max. and min. transmission Refinement method Data 1restraints 1parameters Goodness-of-fit on F2 Final R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole liu9 CI8 HI8 B F3N20 3 S 410.21 173(2) K 0.71073 A Monoclinic P2(1)/n a = 9.3812(9) A b = 14.3671(13) A c = 14.2217(13) A 1882.0(3) A3 4 1.448 Mg/m3 0.223 rnm- 1 848 0.36 x 0.31 x 0.24 rnm3 2.03 to 27.00°. -11<=h<=11, -18<=k<=18, -18<=1<=18 17178 4101 [R(int) = 0.0255] 100.0 % Semi-empirical from equivalents 0.9485 and 0.9241 Full-matrix least-squares on F2 4101/0/325 1.024 R1 = 0.0376, wR2 = 0.1050 R1 = 0.0451, wR2 = 0.1131 0.380 and -0.287 e.A3 214 Table 14. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (A2x 103) for 14a. U(eq) is defmed as one third of the trace of the orthogonalized uij tensor. x y z U(eq) S(I) 417(1) 2337(1) 10006(1 ) 27(1) 0(1) 297(1) 1340(1) 9974(1) 42(1) 0(2) 1816(1) 2682(1) 9897(1) 43(1) 0(3) -221(2) 2781(1) 10730(1) 48(1) N(I) 10850(1) 5609(1) 6297(1) 25(1) N(2) 8700(1) 5098(1) 7038(1) 25(1) B(I) 10005(2) 4880(1) 6572(1) 25(1) C(I) 12010(2) 5388(1) 5878(1) 30(1) C(2) 12377(2) 4497(1) 5715(1) 34(1) C(3) 11570(2) 3745(1) 5975(1) 35(1) C(4) 10387(2) 3894(1) 6391(1) 33(1) C(5) 10605(2) 6621(1) 6394(1) 31(1) C(6) 11710(2) 7055(1) 7189(1) 40(1) C(7) 7408(2) 4697(1) 6663(1) 32(1) C(8) 6215(2) 4800(1) 7078(1) 31(1) C(9) 6291(2) 5314(1) 7923(1) 25(1) C(lO) 7634(2) 5729(1) 8291(1) 26(1) C(1l) 8792(2) 5617(1) 7845(1) 26(1) C(12) 5042(2) 5390(1) 8411(1) 25(1) C(13) 3905(2) 4749(1) 8219(1) 30(1) C(14) 2764(2) 4779(1) 8710(1) 34(1) C(15) 2727(2) 5461(1) 9392(1) 35(1) C(16) 3834(2) 6107(1) 9582(1) 35(1) C(17) 4990(2) 6076(1) 9102(1) 30(1) C(18) -769(2) 2684(1) 890 I(I) 36(1) F(I) -784(2) 3606(1) 8789(1) 71(1) F(2) -2129(1) 2423(1) 8882(1) 63(1) F(3) -360(1) 2323(1) 8134(1) 55(1) Table 15. S(1)-0(3) S(1)-O(1) S(I)-0(2) S(1)-C(18) N(I)-C(I) N(I)-B(I) N(I)-C(5) N(2)-C(7) N(2)-C(11) N(2)-B(1) B(I)-C(4) C(1)-C(2) C(1)-H(1) C(2)-C(3) C(2)-H(2) C(3)-C(4) Bond lengths [A] and angles [0] for 14a. 1.4342(13) 1.4359(13) 1.4388(12) 1.8146(19) 1.3736(19) 1.413(2) 1.482(2) 1.356(2) 1.357(2) 1.531(2) 1.496(2) 1.358(2) 0.959(19) 1.408(3) 0.91(2) 1.369(2) C(3)-H(3) C(4)~H(4) C(5)~C(6) C(5)-H(5A) C(5)-H(5B) C(6)-H(6A) C(6)-H(6B) C(6)-H(6C) C(7)-C(8) C(7)-H(7) C(8)-C(9) C(8)-H(8) C(9)-C(10) C(9)-C(12) C(10)-C(11) C(1O)-H(10) C(11)-H(1l) C(12)-C(13) C(12)-C(17) C(13)-C(14) C(13)-H(13) C(14)-C(15) C(14)-H(14) C(15)-C(16) C(15)-H(15) C(16)-C(17) C(16)-H(16) C(17)-H(17) C(18)-F(2) C(18)-F(3) C(18)-F(1) 0(3)-8(1)-0(1) 0(3)-8(1)-0(2) 0(1)-8(1 )-0(2) 0(3)-8(1)-C(18) 0(1)-8(1 )-C(18) 0(2)-8(1 )-C(18) C(1)-N(1)-B(1 ) C(1)-N(1)-C(5) B(1)-N(1)-C(5) C(7)-N(2)-C(11) C(7)-N(2)-B(1) C(11)-N(2)-B(1) N(1)-B(1)-C(4) N(1)-B(1)-N(2) C(4)-B(1)-N(2) C(2)-C(1)-N(1) C(2)-C(1 )-H(1 ) N(1)-C(1)-H(1 ) C(1 )-C(2)-C(3) C(1)-C(2)-H(2) C(3)-C(2)-H(2) C(4)-C(3)-C(2) 0.938(19) 0.98(2) 1.515(3) 0.986(19) 0.94(2) 1.00(3) 0.91(2) 0.98(2) 1.368(2) 0.94(2) 1.401(2) 0.923(19) 1.402(2) 1.475(2) 1.367(2) 0.912(19) 0.930(19) 1.397(2) 1.399(2) 1.385(2) 0.975(19) 1.385(3) 0.96(2) 1.381(3) 0.90(2) 1.387(2) 0.97(2) 0.97(2) 1.326(2) 1.328(2) 1.333(2) 115.18(9) 115.88(8) 114.10(8) 103.21(8) 102.45(8) 103.50(8) 118.77(14) 114.61(13) 126.61(13) 118.28(13) 118.14(13) 123.40(12) 119.29(14) 120.27(14) 120.44(14) 122.62(15) 120.5(11) 116.9(11) 120.85(15) 118.7(13) 120.5(13) 120.90(16) 215 --- ~ ~ ~~ ~~------- C(4)-C(3)-H(3) C(2)-C(3)-H(3) C(3)-C(4)-B(1) C(3)-C(4)-H(4) B(1)-C(4)-H(4) N(l)-C(5)-C(6) N(l)-C(5)-H(5A) C(6)-C(5)-H(5A) N(1 )-C(5)-H(5B) C(6)-C(5)-H(5B) H(5A)-C(5)-H(5B) C(5)-C(6)-H(6A) C(5)-C(6)-H(6B) H(6A)-C(6)-H(6B) C(5)-C(6)-H(6C) H(6A)-C(6)-H(6C) H(6B)-C(6)-H(6C) N(2)-C(7)-C(8) N(2)-C(7)-H(7) C(8)-C(7)-H(7) C(7)-C(8)-C(9) C(7)-C(8)-H(8) C(9)-C(8)-H(8) C(8)-C(9)-C(10) C(8)-C(9)-C(12) C(10)-C(9)-C(12) C(11)-C(10)-C(9) C(11)-C(10)-H(10) C(9)-C(1 0)-H(1 0) N(2)-C(11)-C(10) N(2)-C(11)-H(11) C(10)-C(11)-H(11) C(13)-C(12)-C(17) C(13)-C(12)-C(9) C(17)-C(12)-C(9) C(14)-C(13)-C(12) C(14)-C(13)-H(13) C(12)-C(13)-H(13) C(15)-C(14)-C(13) C(15)-C(14)-H(14) C(13)-C(14)-H(14) C(16)-C(15)-C(14) C(16)-C(15)-H(15) C(14)-C(15)-H(15) C(15)-C(1 6)-C(17) C(15)-C(16)-H(16) C(17)-C(16)-H(16) C(16)-C(17)-C(12) C(16)-C(17)-H(17) C(12)-C(17)-H(17) F(2)-C(18)-F(3) F(2)-C(18)-F(1) F(3)-C(18)-F(1) 121.0(12) 118.1(12) 117.57(16) 118.0(12) 124.3(12) 112.13(14) 108.4(11) 111.0(11) 108.8(12) 109.3(12) 107.1(16) 109.5(15) 109.9(16) 109(2) 112.1(13) 107.2(19) 109(2) 121.87(15) 115.9(11) 122.2(12) 120.96(14) 118.0(11) 121.0(11) 116.08(14) 121.88(13) 122.02(13) 120.88(14) 117.3(11) 121.8(11) 121.91(14) 116.7(11) 121.3(11) 118.32(14) 120.28(14) 121.35(13) 121.03(16) 115.9(11) 123.1(10) 119.99(16) 120.7(12) 119.3(12) 119.70(15) 120.6(13) 119.7(13) 120.70(16) 120.9(11) 118.4(11) 120.25(15) 119.1(11) 120.7(11) 107.47(16) 106.86(15) 106.71(15) 216 217 F(2)-C(18)-S(1 ) 111.65(13) F(3)-C(18)-S(l) 112.25(12) F(1 )-C(18)-S(l) 111.59(14) Symmetry transfonnations used to generate equivalent atoms: Table 16. Anisotropic displacement parameters (A2x 103)for 14a. The anisotropic displacement factor exponent takes the fonn: -2p2[ h2a*2U 11 + ... + 2 h k a* b* U 12 ] Ul1 U22 U33 U23 U13 U12 S(1) 23(1) 33(1) 27(1) -3(1) 7(1) -1(1) 0(1) 43(1) 33(1) 53(1) 10(1) 15(1) 4(1) 0(2) 27(1) 54(1) 49(1) -14(1) 11(1) -12(1) 0(3) 43(1) 67(1) 38(1) -18(1 ) 15(1) 2(1) N(1) 22(1) 29(1) 23(1) 1(1) 4(1) 2(1) N(2) 25(1) 29(1) 22(1) -2(1) 6(1) -4(1) B(1) 26(1) 31(1) 19(1) 0(1) 3(1) 1(1) C(1) 24(1) 43(1) 24(1) 1(1) 5(1) -1(1) C(2) 26(1) 51(1) 24(1) -4(1) 4(1) 9(1) C(3) 41(1) 34(1) 27(1) -5(1) 1(1) 12(1) C(4) 40(1) 30(1) 29(1) -1(1) 6(1) -1(1) C(5) 36(1) 26(1) 33(1) 5(1) 9(1) 1(1) C(6) 47(1) 31(1) 43(1) -4(1) 13(1) -9(1) C(7) 31(1) 40(1) 24(1) -7(1) 6(1) -9(1) C(8) 26(1) 42(1) 26(1) -6(1) 4(1) -8(1) C(9) 24(1) 26(1) 23(1) 3(1) 3(1) -1(1) C(10) 27(1) 27(1) 25(1) -4(1) 4(1) ~2(1) C(l1) 24(1) 28(1) 26(1) -3(1) 4(1) -4(1) C(12) 23(1) 27(1) 24(1) 4(1) 3(1) 2(1) C(13) 29(1) 33(1) 27(1) 1(1) 4(1) -3(1) C(14) 26(1) 42(1) 34(1) 8(1) 5(1) -4(1) C(15) 28(1) 46(1) 33(1) 11(1) 11(1) 8(1) C(16) 34(1) 37(1) 33(1) 1(1) 9(1) 9(1) C(17) 28(1) 29(1) 32(1) 1(1) 6(1) 2(1) C(18) 32(1) 41 (1) 38(1) 4(1) 10(1) 3(1) F(1) 86(1) 46(1) 83(1) 27(1) 18(1) 20(1) F(2) 26(1) 105(1) 57(1) 4(1) 1(1) -2(1) F(3) 56(1) 81(1) 29(1) -2(1) 10(1) 3(1) Table 17. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2x 103) for 14a. x y z U(eq) H(1) 12570(20) 5897(13) 5707(13) 37(5) H(2) 13160(20) 4393(14) 5443(15) 45(5) H(3) 11890(20) 3140(14) 5882(14) 38(5) H(4) 9880(20) 3352(14) 6583(14) 42(5) 218 H(5A) 9610(20) 6713(13) 6507(13) 35(5) H(5B) 10660(20) 6913(14) 5811(15) 37(5) H(6A) 12710(30) 6924( 18) 7076( 18) 70(7) H(6B) 11570(30) 7680(17) 7197(18) 59(7) H(6C) 11650(20) 6798(15) 7817(16) 50(6) H(7) 7370(20) 4366(13) 6086( 14) 37(5) H(8) 5350(20) 4545( 13) 6768(13) 35(5) H(IO) 7781(19) 6069( 12) 8842(14) 29(4) H(II) 9690(20) 5879( 13) 8092(13) 33(5) H(13) 3841(19) 4270(13) 7727(13) 31 (5) H(14) 2020(20) 4316(14) 8582(14) 39(5) H(15) 1980(20) 5479(14) 9708(15) 43(5) J-I( 16) 3830(20) 6587(14) 10059(14) 36(5) J-I( 17) 5760(20) 6531(13) 9257(14) 36(5) , I ~. \1 ., j(-1~(()i" I Figure 11. ORTEP illustration of14b, with ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of 14b suitable for X-ray diffraction were obtained by evaporation of a solution of 14b in CH2Ch. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was 219 solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2• All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for ClOHISBF3N03PS are given in the following tables. Table 18. Crystal data and structure refmement for 14b (liu29). a = 108.031(2t. ~ = 106.341(2t· 'Y = 90.357(2t· Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 27.000 Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters liu29 ClO HIs B F3 N 0 3 P S 331.09 173(2) K 0.71073 A Triclinic P-l a = 8.3208(13) A b = 8.7590(13) A c= 11.6164(17) A 768.5(2) A3 2 1.431 Mg/m3 0.350 mm- 1 344 0.38 x 0.16 x 0.14 mm3 1.93 to 27.000 • -1O<=h<=10, -11 <=k<=II, -14<=1<=14 7185 3253 [R(int) = 0.0249] 96.7% Semi-empirical from equivalents 0.9526 and 0.8784 Full-matrix least-squares on F2 3253/0/253 Goodness-of-fit on F2 Final R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole 1.020 R1 = 0.0430, wR2 = 0.0949 R1 = 0.0598, wR2 = 0.1066 0.394 and -0.318 e.A-3 220 Table 19. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2x 103) for 14b. U(eq) is defmed as one third of the trace of the orthogonalized Uij tensor. x y z U(eq) P(1) 5606(1) 8361(1) 7055(1) 23(1) S(1) 1339(1) 6979(1) 3056(1) 27(1) 0(1) 1688(3) 8684(2) 3361(2) 52(1) 0(2) 430(2) 6148(2) 1759(2) 43(1) 0(3) 2727(2) 6212(2) 3613(2) 45(1) N(1) 7758(2) 8666(2) 9647(2) 23(1) B(1) 6856(3) 9477(3) 8821(2) 24(1) F(1) -1564(2) 7452(3) 3468(2) 86(1) F(2) -588(3) 5287(3) 3715(2) 91(1) F(3) 446(2) 7573(2) 5130(2) 61(1) C(1) 8637(3) 9518(3) 10870(2) 29(1) C(2) 8690(3) 11150(3) 11334(2) 31(1) C(3) 7848(3) 12036(3) 10569(2) 31(1) C(4) 6926(3) 11270(3) 9335(2) 29(1) C(5) 7842(3) 6892(3) 9283(2) 28(1) C(6) 6634(4) 6071(4) 9718(3) 38(1) C(7) 4350(4) 9787(3) 6492(3) 34(1) C(8) 4207(3) 6639(3) 6787(3) 33(1) C(9) 6905(3) 7656(3) 6034(2) 31(1) C(10) -165(3) 6837(4) 3889(3) 45(1) Table 20. Bond lengths [A] and angles [0] for 14b. P(1)-C(8) 1.792(3) P(1)-C(7) 1.794(2) P(1)-C(9) 1.798(2) P(1)-B(1) 1.947(3) S(1)-0(2) 1.4299(17) S(1)-O(1) 1.432(2) S(1)-0(3) 1.4361(17) S(1)-C(10) 1.809(3) N(1)-C(1) 1.365(3) N(1)-B(1) 1.419(3) N(1)-C(5) 1.486(3) B(1)-C(4) 1.492(3) F(1)-C(lO) 1.317(3) F(2)-C(10) 1.339(4) F(3)-C(10) 1.327(3) C(1)-C(2) 1.358(3) C(1)-H(1) 0.95(3) C(2)-C(3) 1.402(3) C(2)-H(2) C(3)-C(4) C(3)-H(3) C(4)-H(4) C(5)-C(6) C(5)-H(5A) C(5)-H(5B) C(6)-H(6A) C(6)-H(6B) C(6)-H(6C) C(7)-H(7A) C(7)-H(7B) C(7)-H(7C) C(8)-H(8A) C(8)-H(8B) C(8)-H(8C) C(9)-H(9A) C(9)-H(9B) C(9)-H(9C) C(8)-P(1)-C(7) C(8)-P(1)-C(9) C(7)-P(1)-C(9) C(8)-P(1)-B(1) C(7)-P(1)-B(1) C(9)-P(1)-B(1) 0(2)-S(1)-0(1 ) 0(2)-S( 1)-0(3) 0(1 )-S(1)-0(3) 0(2)-S(1)-C(10) 0(1 )-S(1 )-C(1 0) 0(3)-S(1)-C(10) C(l)-N(1)-B(1) C(1 )-N(1 )-C(5) B(1)-N(1)-C(5) N(1 )-B(1 )-C(4) N(1)-B(1)-P(l) C(4)-B(1)-P(1) C(2)-C(1)-N(1) C(2)-C(1)-H(1) N(1)-C(l)-H(1) C(1)-C(2)-C(3) C(1)-C(2)-H(2) C(3)-C(2)-H(2) C(4)-C(3)-C(2) C(4)-C(3)-H(3) C(2)-C(3)-H(3) C(3)-C(4)-B(1) C(3)-C(4)-H(4) B(l)-C(4)-H(4) N(1)-C(5)-C(6) N(l )-C(5)-H(5A) C(6)-C(5)-H(5A) N(1)-C(5)-H(5B) 0.89(3) 1.368(3) 0.99(3) 0.96(3) 1.511(4) 0.97(2) 0.94(2) 0.96(3) 0.96(3) 0.95(3) 0.95(3) 0.93(3) 1.01(3) 0.96(3) 0.92(3) 0.94(3) 0.91(3) 0.91(3) 1.00(3) 107.27(13) 105.49(13) 107.20(13) 115.28(12) 106.81(12) 114.34(12) 114.75(11) 115.94(11) 114.16(13) 103.25(13) 102.95(14) 103.37(12) 120.2(2) 115.20(18) 124.60(19) 117.7(2) 122.91(18) 119.37(17) 121.8(2) 124.2(15) 114.0(15) 121.2(2) 118.3(16) 120.5(16) 120.6(2) 120.5(15) 118.8(15) 118.5(2) 117.4(15) 124.0(15) 112.1(2) 106.7(13) 112.1(14) 108.6(14) 221 C(6)-C(5)-H(5B) 110.6(14) H(5A)-C(5)-H(5B) 106.6(19) C(5)-C(6)-H(6A) 112.7(18) C(5)-C(6)-H(6B) 112.9(16) H(6A)-C(6)-H(6B) 105(2) C(5)-C(6)-H(6C) 108.2(18) H(6A)-C(6)-H(6C) 110(2) H(6B)-C(6)-H(6C) 108(2) P(1 )-C(7)-H(7A) 109.7(17) P(1)-C(7)-H(7B) 110.8(18) H(7A)-C(7)-H(7B) 109(2) P(1)-C(7)-H(7C) 110.6(15) H(7A)-C(7)-H(7C) 109(2) H(7B)-C(7)-H(7C) 108(2) P(1 )-C(8)-H(8A) 110.5(17) P(1)-C(8)-H(8B) 110.2(18) H(8A)-C(8)-H(8B) 110(2) P(1 )-C(8)-H(8C) 108.3(17) H(8A)-C(8)-H(8C) 106(2) H(8B)-C(8)-H(8C) 111(2) P(1)-C(9)-H(9A) 109.8(17) P(1)-C(9)-H(9B) 109.4(18) H(9A)-C(9)-H(9B) 106(2) P(1 )-C(9)-H(9C) 107.4(15) H(9A)-C(9)-H(9C) 112(2) H(9B)-C(9)-H(9C) 113(2) F(1 )-C(10)-F(3) 108.2(3) F(1)-C(10)-F(2) 107.1(2) F(3)-C(10)-F(2) 107.1(2) F(1)-C(10)-S(1) 111.80(19) F(3)-C(1O)-S(1) 112.46(19) F(2)-C(1O)-S(1) 109.9(2) Symmetry transformations used to generate equivalent atoms: 222 Table 21. Anisotropic displacement parameters (A2x 103)for 14b. The anisotropic displacement factor exponent takes the form: _2p2[ h2a*2U ll + ... + 2 h k a* b* Ul2 ] UII U22 U33 U23 Ul3 Ul2 P(1) 25(1) 22(1) 23(1) 7(1) 5(1) 3(1) S(1) 29(1) 26(1) 25(1) 8(1) 5(1) 4(1) 0(1) 74(1) 34(1) 49(1) 16(1) 14(1) -10(1) 0(2) 51(1) 42(1) 26(1) 5(1) 0(1) 12(1) 0(3) 38(1) 59(1) 35(1) 14(1) 5(1) 22(1) N(1) 25(1) 22(1) 24(1) 9(1) 7(1) 4(1) B(1) 23(1) 26(1) 24(1) 9(1) 8(1) 2(1) F(1) 41(1) 163(2) 74(1) 58(2) 23(1) 45(1) F(2) 86(2) 96(2) 95(2) 52(1) 10(1) -45(1) F(3) 52(1) 100(2) 40(1) 26(1) 23(1) 15(1) C(1) 28(1) 34(1) 26(1) 13(1) 6(1) 6(1) C(2) 31(1) 34(1) 22(1) 3(1) 4(1) -1(1) C(3) 35(1) 23(1) 33(1) 3(1) 11(1) 3(1) C(4) 34(1) 23(1) 30(1) 10(1) 8(1) 5(1) 223 C(5) 30(1) 23(1) 32(1) 12(1) 6(1) 8(1) C(6) 41(2) 31(2) 46(2) 21(1) 13(1) 2(1) C(7) 36(1) 30(2) 30(1) 10(1) 1(1) 5(1) C(8) 32(1) 33(2) 33(1) 13(1) 7(1) -3(1) C(9) 36(1) 29(1) 29(1) 7(1) 13(1) 2(1) C(10) 30(1) 67(2) 44(2) 28(2) 6(1) 3(1) Table 22. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2x 103) for 14b. x y z U(eq) H(1) 9180(30) 8870(30) 11350(20) 34(7) H(2) 9300(30) 11650(30) 12130(20) 31(7) H(3) 7980(30) 13230(30) 10920(20) 43(8) H(4) 6410(30) 11940(30) 8840(20) 35(7) H(5A) 7610(30) 6500(30) 8370(20) 23(6) H(5B) 8950(30) 6700(30) 9630(20) 22(6) H(6A) 6870(40) 6440(30) 10620(30) 49(8) H(6B) 5490(40) 6270(30) 9400(20) 40(7) H(6C) 6710(40) 4940(40) 9420(30) 51(8) H(7A) 3610(40) 10150(30) 6990(30) 50(8) H(7B) 3720(40) 9320(40) 5650(30) 52(9) H(7C) 5090(40) 10740(40) 6550(30) 48(8) H(8A) 3470(40) 6920(30) 7310(30) 46(8) H(8B) 4810(30) 5820(30) 6950(30) 43(8) H(8C) 3520(40) 6320(30) 5950(30) 45(8) H(9A) 7670(40) 8470(40) 6140(20) 41(8) H(9B) 7510(40) 6890(40) 6270(30) 45(8) H(9C) 6140(30) 7250(30) 5140(30) 45(8) Table 23. Torsion angles [0] for 14b. C(1)-N(1)-B(1)-C(4) C(5)-N(1)-B(1)-C(4) C(1 )-N(1 )-B(1)-P(1) C(5)-N(1 )-B(1 )-P(1) C(8)-P(1)-B(1)-N(1) C(7)-P(1 )-B(1 )-N(1 ) C(9)-P(1)-B(1)-N(1) C(8)-P(1)-B(1)-C(4) C(7)-P(1)-B(1)-C(4) C(9)-P(1)-B(1)-C(4) B(1 )-N(1 )-C(1 )-C(2) C(5)-N(1 )-C(1 )-C(2) N(1)-C(1)-C(2)-C(3) C(1)-C(2)-C(3)-C(4) C(2)-C(3)-C(4)-B(l) N(1)-B(1)-C(4)-C(3) P(1)-B(1)-C(4)-C(3) C(1)-N(1)-C(5)-C(6) B(1)-N(1 )-C(5)-C(6) O(2)-S(1)-C(10)-F(1) 0.7(3) -179.1(2) 178.76(17) -1.0(3) 49.6(2) 168.7(2) -72.9(2) -132.4(2) -13.3(2) 105.1(2) -0.5(3) 179.3(2) -0.4(4) 1.0(4) -0.7(4) -0.1(3) -178.25(18) 80.7(3) -99.5(3) -57.0(3) 224 O( I)-S( I)-C(l O)-F( I) 0(3)-S( I )-C( JO)-F( I) 0(2)-S( 1)-C( 10)-F(3) O( I)-S( 1)-C( 10)-F(3) 0(3)-S( I )-C( I0)-F(3) 0(2)-S( I )-C( I0)-F(2) O( 1)-S( 1)-C( 10)-F(2) 0(3)-S( 1)-C( 10)-F(2) 62.7(2) -178.2(2) -179.1(2) -59.3(2) 59.8(2) 61.7(2) -178.57( 18) -59.5(2) Symmetry trans[OImations used to generate equivalent atoms: l I f<:/ , I (7/ 01 \ )\ r~I~( {,V «(~'l ( /) ~I C) / / ((4':~ C'i Figure 12. ORTEP illustration of 14c, with ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of 14c suitable for X- ray diffraction were obtained by evaporation of a solution of 14c in CH2CIz. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2• All non-H atoms were refined with anisotropic thennal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software 225 and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for C25H24BF3N04PS are given in the following tables. Table 24. Crystal data and structure refmement for 14c. a = 90°. ~ = 90°. y = 90°. Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 27.00° Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters Goodness-of-fit on F2 Final R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole liu25 C25 H24 B F3N 04 P S 533.29 173(2) K 0.71073 A Orthorhombic Pbca a = 9.1044(4) A b = 19.8146(8) A c = 28.1910(11) A 5085.7(4) A3 8 1.393 Mg/m3 0.245 mm- 1 2208 0.26 x 0.20 x 0.12 mm3 1.44 to 27.00°. -11 <=h<=10, -25<=k<=25, -36<=1<=36 48806 5550 [R(int) = 0.0393] 100.0 % Semi-empirical from equivalents 0.9712 and 0.9391 Full-matrix least-squares on F2 5550/0/421 1.057 Rl = 0.0450, wR2 = 0.1094 Rl = 0.0550, wR2 = 0.1169 0.450 and -0.272 e.A-3 226 Table 25. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2x 103) for 14c. U(eq) is defmed as one third of the trace of the orthogonalized uij tensor. x y z U(eq) P(1) 9768(1) 595(1) 6290(1) 23(1) S(1) 6965(1) 1870(1) 3602(1) 32(1) N(1) 7259(2) 2118(1) 5950(1) 28(1) 0(1) 8967(2) 1285(1) 6241(1) 28(1) 0(2) 6775(2) 1168(1) 3496(1) 53(1) 0(3) 5761(2) 2166(1) 3856(1) 49(1) 0(4) 8385(2) 2063(1) 3770(1) 64(1) B(1) 8277(2) 1598(1) 5840(1) 26(1) C(1) 6478(2) 2421(1) 5595(1) 33(1) C(2) 6659(2) 2255(1) 5131(1) 37(1) C(3) 7686(3) 1763(1) 4999(1) 39(1) C(4) 8500(2) 1421(1) 5329(1) 35(1) C(5) 6995(3) 2348(1) 6445(1) 36(1) C(6) 5949(3) 1890(1) 6701(1) 41(1) C(7) 8706(2) -77(1) 6045(1) 26(1) C(8) 7589(2) -354(1) 6319(1) 35(1) C(9) 6699(2) -857(1) 6136(1) 39(1) C(10) 6925(2) -1086(1) 5679(1) 38(1) C(11) 8036(3) -817(1) 5405(1) 42(1) C(12) 8932(3) -315(1) 5585(1) 36(1) C(13) 11516(2) 648(1) 6009(1) 29(1) C(14) 12314(3) 69(1) 5902(1) 43(1) C(15) 13704(3) 141(2) 5701(1) 58(1) C(16) 14264(3) 774(2) 5606(1) 59(1) C(17) 13464(3) 1341(2) 5709(1) 53(1) C(18) 12089(2) 1287(1) 5912(1) 39(1) C(19) 9865(2) 440(1) 6913(1) 25(1) C(20) 10490(2) -161(1) 7067(1) 34(1) C(21) 10369(3) -343(1) 7540(1) 40(1) C(22) 9630(3) 68(1) 7854(1) 38(1) C(23) 9043(3) 672(1) 7704(1) 37(1) C(24) 9159(2) 865(1) 7231(1) 31(1) C(25) 6839(3) 2259(1) 3023(1) 41(1) F(1) 7865(2) 2048(1) 2731(1) 80(1) F(2) 5549(2) 2133(1) 2822(1) 72(1) F(3) 6969(2) 2927(1) 3045(1) 72(1) Table 26. Bond lengths [A] and angles [0] for 14c. 227 P(1)-O(1) P(1)-C(13) P(1)-C(7) P(1)-C(19) S(1)-0(4) S(1)-0(2) S(1)-0(3) S(1)-C(25) N(1)-C(1) N(1)-B(1) N(1)-C(5) O(1)-B(1) B(1)-C(4) C(1)-C(2) C(1)-H(1) C(2)-C(3) C(2)-H(2) C(3)-C(4) C(3)-H(3) C(4)-H(4) C(5)-C(6) C(5)-H(5A) C(5)-H(5B) C(6)-H(6A) C(6)-H(6B) C(6)-H(6C) C(7)-C(8) C(7)-C(12) C(8)-C(9) C(8)-H(8) C(9)-C(10) C(9)-H(9) C(1 0)-C(11) C(10)-H(10) C(11)-C(12) C(11)-H(11) C(12)-H(12) C(13)-C(14) C(13)-C(18) C(14)-C(15) C(14)-H(14) C(15)-C(16) C(15)-H(15) C(16)-C(17) C(16)-H(16) C(17)-C( 18) C(17)-H(17) C(18)-H(18) C(19)-C(24) C(19)-C(20) C(20)-C(21) C(20)-H(20) 1.5563(13) 1.781(2) 1.7845(19) 1.7846(18) 1.4285(18) 1.4336(17) 1.4349(17) 1.810(2) 1.368(2) 1.420(3) 1.487(3) 1.433(2) 1.496(3) 1.357(3) 0.95(2) 1.403(3) 0.94(3) 1.369(3) 0.93(3) 1.00(3) 1.501(3) 0.99(2) 0.99(2) 1.03(3) 1.00(3) 1.00(2) 1.390(3) 1.394(3) 1.384(3) 0.95(2) 1.380(3) 0.93(3) 1.379(3) 0.93(2) 1.382(3) 0.96(3) 0.94(3) 1.391(3) 1.397(3) 1.395(4) 0.92(3) 1.381(5) 0.85(3) 1.370(4) 0.97(3) 1.381(3) 1.00(3) 0.98(2) 1.387(3) 1.391(3) 1.385(3) 0.93(3) C(21 )-C(22) C(21)-H(21) C(22)-C(23) C(22)-H(22) C(23)-C(24) C(23)-H(23) C(24)-H(24) C(25)-F(1) C(25)-F(2) C(25)-F(3) 0(1 )-P(1 )-C(13) 0(1 )-P(1 )-C(7) C(13)-P(1)-C(7) 0(1)-P(1)-C(19) C(13)-P(1 )-C(19) C(7)-P(1)-C(19) 0(4)-S(1)-0(2) 0(4)-S(1)-0(3) 0(2)-S(1)-0(3) 0(4)-S(1 )-C(25) 0(2)-S(1)-C(25) 0(3)-S(1)-C(25) C(1)-N(1)-B(1) C(1)-N(1)-C(5) B(1)-N(1)-C(5) B(1)-O(1)-P(1) N(1)-B(1)-O(1) N(1)-B(1)-C(4) 0(1 )-B(1)-C(4) C(2)-C(1)-N(1) C(2)-C(1)-H(1) N(l)-C(l)-H(l) C(1)-C(2)-C(3) C(1)-C(2)-H(2) C(3)-C(2)-H(2) C(4)-C(3)-C(2) C(4)-C(3)-H(3) C(2)-C(3)-H(3) C(3)-C(4)-B(1 ) C(3)-C(4)-H(4) B(1)-C(4)-H(4) N(1)-C(5)-C(6) N(1)-C(5)-H(5A) C(6)-C(5)-H(5A) N(1 )-C(5)-H(5B) C(6)-C(5)-H(5B) H(5A)-C(5)-H(5B) C(5)-C(6)-H(6A) C(5)-C(6)-H(6B) H(6A)-C(6)-H(6B) C(5)-C(6)-H(6C) H(6A)-C(6)-H(6C) H(6B)-C(6)-H(6C) 1.378(3) 0.94(3) 1.378(3) 0.92(3) 1.391(3) 0.96(3) 0.96(2) 1.312(3) 1.328(3) 1.332(3) 109.08(9) 111.54(8) 110.83(9) 105.20(8) 113.81(9) 106.26(9) 115.95(13) 114.61(12) 114.13(10) 103.99(11) 102.57(11) 103.23(11) 119.82(17) 117.97(17) 122.21(16) 131.01(12) 115.30(16) 118.01(17) 126.68(18) 122.4(2) 121.0(14) 116.6(14) 120.37(19) 117.0(15) 122.7(15) 121.6(2) 119.8(16) 118.5(15) 117.7(2) 117.4(14) 124.9(14) 111.65(18) 113.7(13) 109.1(14) 108.1(13) 112.1(13) 101.9(19) 110.7(17) 108.1(14) 110(2) 110.0(14) 109(2) 109(2) 228 C(8)-C(7)-C(12) C(8)-C(7)-P(1) C(12)-C(7)-P(1) C(9)-C(8)-C(7) C(9)-C(8)-H(8) C(7)-C(8)-H(8) C(10)-C(9)-C(8) C(10)-C(9)-H(9) C(8)-C(9)-H(9) C(11)-C(10)-C(9) C(11)-C(10)-H(10) C(9)-C(10)-H(10) C(1O)-C(11)-C(12) C(10)-C(11)-H(11) C(12)-C(11)-H(11) C(11)-C(12)-C(7) C(11)-C(12)-H(12) C(7)-C(12)-H(12) C(14)-C(13)-C(18) C(14)-C(13)-P(1) C(18)-C(13)-P(1 ) C(13)-C(14)-C(15) C(13)-C(14)-H(14) C(15)-C(14)~H(14) C(16)-C(15)-C(14) C(16)-C(15)-H(15) C(14)-C(15)-H(15) C(17)-C(16)-C(15) C( 17)-C(16)-H(16) C(15)-C(16)-H(16) C(16)-C(17)-C(18) C(16)-C(17)-H(17) C(18)-C(17)-H(17) C(17)-C(18)-C(13) C(17)-C(18)-H(18) C(13)-C(18)-H(18) C(24)-C(19)-C(20) C(24)-C(19)-P(1) C(20)-C(19)-P(1 ) C(21 )-C(20)-C(19) C(21 )-C(20)-H(20) C(19)-C(20)-H(20) C(22)-C(21 )-C(20) C(22)-C(21)-H(21) C(20)-C(21 )-H(21 ) C(23)-C(22)-C(21 ) C(23)-C(22)-H(22) C(21 )-C(22)-H(22) C(22)-C(23)-C(24) C(22)-C(23)-H(23) C(24)-C(23)-H(23) C(19)-C(24)-C(23) C(19)-C(24)-H(24) 119.35(18) 118.40(14) 122.21(15) 120.35(19) 118.8(15) 120.8(15) 119.8(2) 118.9(15) 121.3(15) 120.3(2) 119.3(15) 120.4(15) 120.3(2) 121.6(16) 118.1(16) 119.9(2) 120.5(15) 119.6(15) 120.7(2) 120.95(17) 118.32(16) 118.6(3) 119.4(15) 122.0(15) 120.4(3) 126.8(18) 112.7(18) 120.5(2) 122.2(18) 117.2(18) 120.5(3) 118.3(19) 121.2(19) 119.3(2) 119.9(14) 120.8(14) 120.44(18) 120.64(14) 118.35(15) 119.4(2) 119.0(15) 121.6(15) 120.2(2) 120.2(15) 119.6(15) 120.41(19) 119.1(16) 120.4(16) 120.1(2) 123.0(15) 116.8(15) 119.32(19) 122.0(13) 229 230 C(23)-C(24)-H(24) 118.6(13) F(1 )-C(25)-F(2) 107.7(2) F(1)-C(25)-F(3) 106.5(2) F(2)-C(25)-F(3) 106.6(2) F(1 )-C(25)-S(1) 112.63(17) F(2)-C(25)-S(1) 111.10(16) F(3)-C(25)-S(1 ) 112.03(16) Symmetry transformations used to generate equivalent atoms: Table 27. Anisotropic displacement parameters (A2x 103)for 14c. The anisotropic displacement factor exponent takes the form: _2p2[ h2a*2U11 + ... + 2 h k a* b* U 12 ] Ull U22 U33 U23 UB U12 P(1) 23(1) 25(1) 20(1) 1(1) -1 (1) 2(1) S(1) 30(1) 34(1) 32(1) 8(1) -2(1) -5(1) N(1) 27(1) 26(1) 30(1) 4(1) 0(1) 0(1) 0(1) 32(1) 28(1) 24(1) 2(1) -1(1) 6(1) 0(2) 56(1) 30(1) 74(1) 9(1) 9(1) 3(1) 0(3) 53(1) 46(1) 47(1) -7(1) 15(1) -7(1) 0(4) 42(1) 98(2) 51(1) 23(1) -18(1) -23(1) B(1) 25(1) 28(1) 26(1) 5(1) -1(1) 0(1) C(1) 28(1) 27(1) 44(1) 10(1) -4(1) 1(1) C(2) 35(1) 39(1) 37(1) 16(1) -8(1) -2(1) C(3) 45(1) 48(1) 24(1) 8(1) 0(1) -2(1) C(4) 38(1) 41(1) 26(1) 4(1) 4(1) 7(1) C(5) 40(1) 30(1) 38(1) -6(1) 0(1) 6(1) C(6) 37(1) 52(1) 33(1) -1 (1) 3(1) 3(1) C(7) 25(1) 26(1) 27(1) 0(1) -2(1) 2(1) C(8) 27(1) 43(1) 34(1) -7(1) 5(1) -2(1) C(9) 28(1) 40(1) 48(1) -4(1) 4(1) -5(1) C(10) 33(1) 30(1) 50(1) -8(1) -10(1) 1(1) C(11) 53(2) 42(1) 31(1) -9(1) -2(1) -4(1) C(12) 45(1) 38(1) 26(1) -2(1) 4(1) -8(1) C(13) 23(1) 42(1) 22(1) 2(1) -2(1) 1(1) C(14) 37(1) 53(1) 40(1) 16(1) 6(1) 17(1) C(15) 38(1) 90(2) 46(1) 9(1) 4(1) 33(2) C(16) 25(1) 114(3) 39(1) 4(1) 0(1) -11(1) C(17) 38(1) 79(2) 43(1) -13(1) 6(1) -28(1) C(18) 37(1) 49(1) 31(1) -11(1) 1(1) -15(1) C(19) 24(1) 29(1) 23(1) 2(1) -4(1) -1(1) C(20) 41(1) 32(1) 29(1) 2(1) -3(1) 7(1) C(21) 51(1) 36(1) 33(1) 10(1) -7(1) 4(1) C(22) 42(1) 48(1) 24(1) 7(1) -4(1) -6(1) C(23) 40(1) 47(1) 25(1) -4(1) 0(1) 3(1) C(24) 36(1) 33(1) 25(1) -1 (1) -2(1) 5(1) C(25) 42(1) 46(1) 35(1) 7(1) -3(1) -8(1) F(1) 85(1) 109(2) 46(1) 5(1) 28(1) 2(1) F(2) 63(1) 96(1) 55(1) 18(1) -31(1) -19(1) F(3) 98(1) 45(1) 72(1) 29(1) -11 (1) -17(1) c,) ~,~/-' I.' oj) Figure 13. ORTEP illustration of 14d, with ellipsoids drawn at the 35% probability level. 232 X-ray Crystal Structure Determination. Crystals of 14d suitable for X-ray diffraction were obtained by evaporation ofa solution of 14d in CHzCh. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on FZ. All non-H atoms were refmed with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for C12H14BF3Nz04S are given in the following tables. Table 29. Crystal data and structure refinement for 14d. Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size liu27 C1Z H14B F3Nz 04 S 350.12 173(2) K 0.71073 A Monoclinic P2(1)/c a = 9.6415(13) A b = 9.9617(14) A c = 16.668(2) A 1590.3(4) A3 4 .. ...,._.,. r , 'J l.£f.OL lVlg/mJ 0.254 mm- I 720 0.32 x 0.26 x 0.18 mm3 a = 90°. 13 = 96.612(2)°. Y= 90°. Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 27.00° Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters Goodness-of-fit on p2 Pinal R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole 2.13 to 27.00°. -12<=h<=12, -12<=k<=12, -20<=1<=21 14940 3448 [R(int) = 0.0393] 98.9 % Semi-empirical from equivalents 0.9557 and 0.9232 Pull-matrix least-squares on p2 3448/0/264 1.015 Rl = 0.0433, wR2 = 0.0976 Rl = 0.0688, wR2 = 0.1137 0.280 and -0.269 e.A-3 233 Table 30. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2x 103) for 14d. U(eq) is defmed as one third of the trace of the orthogona1ized Uij tensor. x y z U(eq) S(I) 0(1) 0(2) 0(3) 0(4) N(I) N(2) F(I) F(2) F(3) B(I) C(I) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(lO) C(II) C(12) 6805(1) 9909(2) 8172(2) 6684(2) 6093(2) 7845(2) 11006(2) 5815(2) 4490(1) 6316(2) 8915(2) 6810(2) 6779(2) 7829(2) 8913(2) 7808(3) 8656(3) 10931(2) 12044(2) 13203(2) 13221(2) 12099(2) 5807(2) 1980(1) 10054(2) 2574(2) 693(2) 2107(2) 9045(2) 9997(2) 4335(1) 2722(2) 3131(2) 8994(2) 8096(3) 7119(3) 7017(2) 7903(2) 10061(3) 9661(3) 10756(2) 10742(2) 9978(2) 9215(2) 9236(2) 3084(2) 1154(1) 2287(1) 1232(1) 774(1) 1859(1) 2649(1) 1821(1) 721(1) 294(1) -267(1) 2135(2) 2560(2) 1998(2) 1480(2) 1523(1) 3289(2) 4067(2) 1156(1) 717(2) 972(2) 1658(1) 2086(1) 439(2) 43(1) 42(1) 68(1) 66(1) 51(1) 37(1) 35(1) 76(1) 75(1) 74(1) 36(1) 48(1) 51(1) 48(1) 40(1) 46(1) 57(1) 40(1) 45(1) 44(1) 45(1) 41(1) 45(1) Table 31. S(I)-0(3) S(I)-0(4) S(I)-0(2) S(I)-C(12) Bond lengths [A] and angles [0] for 14d. 1.4288(18) 1.4331(16) 1.4368(18) 1.815(2) 0(1)-N(2) O(1)-B(1) N(1)-C(1) N(1)-B(1) N(1)-C(5) N(2)-C(11) N(2)-C(7) F(1)-C(12) F(2)-C(12) F(3)-C(12) B(1)-C(4) C(1)-C(2) C(1)-H(1) C(2)-C(3) C(2)-H(2) C(3)-C(4) C(3)-H(3) C(4)-H(4) C(5)-C(6) C(5)-H(5A) C(5)-H(5B) C(6)-H(6A) C(6)-H(6B) C(6)-H(6C) C(7)-C(8) C(7)-H(7) C(8)-C(9) C(8)-H(8) C(9)-C(10) C(9)-H(9) C(10)-C(11) C(1O)-H(10) C(11)-H(11) 0(3)-S(1)-0(4) 0(3)-S( 1)-0(2) 0(4)-S(1 )-0(2) 0(3)-S(1 )-C(12) 0(4)-S(1)-C(12) 0(2)-S(1 )-C(12) N(2)-0(1 )-B(1) C(1)-N(1)-B(1) C(1)-N(1)-C(5) B(1)-N(1)-C(5) C(11)-N(2)-C(7) C(11)-N(2)-0(1) C(7)-N(2)-0(1) N(1)-B(1)-O(1) N(1)-B(1)-C(4) 0(1)-B(l)-C(4) C(2)-C(I)-N(1) C(2)-C(1)-H(1 ) N(1)-C(1)-H(1) C(1)-C(2)-C(3) 1.383(2) 1.429(3) 1.371(3) 1.414(3) 1.474(3) 1.332(3) 1.337(3) 1.331(3) 1.316(3) 1.326(3) 1.492(3) 1.349(4) 0.91(3) 1.408(4) 0.91(2) 1.363(3) 0.94(2) 0.90(2) 1.505(4) 0.94(2) 0.96(2) 0.99(3) 0.93(3) 0.98(3) 1.367(3) 0.92(2) 1.378(3) 0.93(2) 1.372(3) 0.90(2) 1.364(3) 0.95(2) 0.92(2) 114.91(11) 115.92(12) 114.22(11) 103.98(11) 102.57(10) 102.76(11) 114.28(15) 118.8(2) 118.3(2) 122.86(19) 124.28(19) 117.64(17) 118.00(17) 112.82(19) 119.8(2) 127.4(2) 122.1(2) 122.6(17) 115.3(17) 121.2(2) 234 235 C(1)-C(2)-H(2) 116.3(16) C(3)-C(2)-H(2) 122.5(16) C(4)-C(3)-C(2) 121.5(2) C(4)-C(3)-H(3) 118.3(14) C(2)-C(3)-H(3) 120.1(14) C(3)-C(4)-B(1) 116.6(2) C(3)-C(4)-H(4) 118.4(14) B(1)-C(4)-H(4) 125.0(14) N(1)-C(5)-C(6) 112.7(2) N(1)-C(5)-H(5A) 109.0(14) C(6)-C(5)-H(5A) 113.6(14) N( 1)-C(5)-H(5B) 108.2(15) C(6)-C(5)-H(5B) 110.7(15) H(5A)-C(5)-H(5B) 102.0(19) C(5)-C(6)-H(6A) 109.8(16) C(5)-C(6)-H(6B) 111.0(18) H(6A)-C(6)-H(6B) 106(2) C(5)-C(6)-H(6C) 108.6(15) H(6A)-C(6)-H(6C) 112(2) H(6B)-C(6)-H(6C) 109(2) N(2)-C(7)-C(8) 117.8(2) N(2)-C(7)-H(7) 115.2(14) C(8)-C(7)-H(7) 127.0(14) C(7)-C(8)-C(9) 120.0(2) C(7)-C(8)-H(8) 118.0(15) C(9)-C(8)-H(8) 122.0(15) C(1O)-C(9)-C(8) 119.7(2) C(1O)-C(9)-H(9) 121.2(15) C(8)-C(9)-H(9) 119.1(15) C(11)-C(10)-C(9) 119.6(2) C(11)-C(10)-H(10) 117.0(14) C(9)-C(1O)-H(10) 123.4(14) N(2)-C(11)-C(10) 118.7(2) N(2)-C(11)-H(11) 114.8(14) C(10)-C(11)-H(11) 126.5(15) F(2)-C(12)-F(3) 107.1(2) F(2)-C(12)-F(1) 106.70(19) F(3)-C(12)-F(l) 107.02(19) F(2)-C(12)-S(l) 112.45(16) F(3)-C(12)-S(l) 112.44(16) F(1)-C(l2)-S(l) 110.76(16) Symmetry transfonnations used to generate equivalent atoms: Table 32. Anisotropic displacement parameters (A2x 103)for 14d. The anisotropic displacement factor exponent takes the fonn: _2p2[ h2a*2U ll + ... + 2 h k a* b* U12 ] S(1) 0(1) 0(2) 0(3) 0(4) 38(1) 41(1) 29(1) 102(2) 47(1) 54(1) 45(1) 107(2) 50(1) 70(1) 38(1) 44(1) 69(1) 47(1) 37(1) -7(1) -8(1) -11(1) -6(1) -5(1) 3(1) 21(1) 4(1) 10(1) 9(1) 14(1) -9(1) 8(1) 23(1) 13(1) 236 N(1) 30(1) 47(1) 35(1) 8(1) 6(1) 1(1) N(2) 35(1) 39(1) 34(1) -5(1) 12(1) -4(1) F(1) 89(1) 43(1) 93(1) -7(1) -4(1) 9(1) F(2) 47(1) 86(1) 85(1) 30(1) -22(1) -13(1) F(3) 95(1) 78(1) 52(1) 15(1) 20(1) 2(1) B(1) 33(1) 40(1) 36(1) 7(1) 3(1) 1(1) C(1) 31(1) 64(2) 48(2) 20(1) 3(1) -1(1) C(2) 37(1) 56(2) 58(2) 13(1) -4(1) -13(1) C(3) 49(1) 42(1) 49(2) 2(1) -9(1) -3(1) C(4) 39(1) 41(1) 40(1) 4(1) 4(1) 1(1) C(5) 42(1) 58(2) 42(1) 3(1) 14(1) 10(1) C(6) 60(2) 68(2) 43(2) -3(1) 6(1) 7(1) C(7) 37(1) 41(1) 43(1) 4(1) 8(1) 2(1) C(8) 48(1) 49(1) 39(1) 5(1) 13(1) -3(1) C(9) 36(1) 51(1) 46(1) -12(1) 14(1) -4(1) C(10) 38(1) 50(1) 45(1) -6(1) 4(1) 5(1) C(11) 43(1) 43(1) 36(1) 0(1) 4(1) 0(1) C(12) 43(1) 45(1) 47(1) -1(1) 4(1) -4(1) Table 33. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2x 103) for 14d. x y z U(eq) H(1) 6150(30) 8180(20) 2899(17) 62(8) H(2) 6060(30) 6530(20) 1983(14) 53(7) H(3) 7820(20) 6300(20) 1111(14) 46(7) H(4) 9580(20) 7780(20) 1189(14) 40(6) H(5A) 6880(30) 10260(20) 3348(13) 47(6) H(5B) 8140(20) 10890(20) 3095(15) 52(7) H(6A) 8290(30) 8820(30) 4268(17) 72(9) H(6B) 9580(30) 9490(30) 3987(17) 79(9) H(6C) 8630(30) 10400(30) 4456(16) 61(8) H(7) 10120(20) 11250(20) 1048(13) 42(6) H(8) 11990(20) 11260(20) 250(15) 56(7) H(9) 13930(20) 9980(20) 676(14) 47(7) H(IO) 13970(20) 8640(20) 1847(14) 52(7) H(11) 12000(20) 8750(20) 2546(15) 49(7) Table 34. Torsion angles [0] for 14d. B(1)-0(1)-N(2)-C(II) -85.5(2) B(1 )-0(1 )-N(2)-C(7) 97.7(2) C(1 )-N(1 )-B(1 )-0(1) 179.08(18) C(5)-N(1 )-B(1 )-0(1 ) -2.2(3) C(1 )-N(1 )-B(1 )-C(4) -1.2(3) C(5)-N(1 )-B(1 )-C(4) 177.53(19) N(2)-0(1 )-B(1 )-N(1 ) 177.08(16) N(2)-0(1 )-B(1)-C(4) -2.6(3) B(1)-N(1 )-C(1 )-C(2) -0.1(3) C(5)-N(1)-C(1 )-C(2) -178.9(2) N(1)-C(1)-C(2)-C(3) 0.9(4) C(1 )-C(2)-C(3)-C(4) -0.3(4) 237 C(2)-C(3)-C(4)-B( J) N( 1)-B( I)-C(4)-C(3) O( I )-B( I )-C(4)-C(3) C( I )-N( I )-C(5)-C(6) B( I )-N( I )-C(5)-C(6) C( II )-N(2)-C(7)-C(8) O( I )-N(2)-C(7)-C(8) N(2)-C(7)-C(8)-C(9) C(7)-C(8)-C(9)-C( I 0) C(8)-C(9)-C( I O)-C( I I) C(7)-N(2)-C( II )-C( 10) O( I )-N(2)-C( II )-C(l 0) C(9)-C( I O)-C( II )-N(2) O(3)-S( I )-C( 12)-F(2) O(4)-S( I )-C( 12)-F(2) O(2)-S( I )-C( 12)-F(2) O(3)-S( J)-C( 12)-F(3) O(4)-S( I )-C( 12)-F(3) O(2)-S( l)-C( 12)-F(3) O(3)-S( 1)-C( 12)-F( I) O(4)-S( I )-C( 12)-F( I) O(2)-S( I)-C( 12)-F( I) Symmetry transformations used to generate equivalent atoms: -0.9(3) 1.7(3) -178.6(2) 93.1 (3) -85.6(3) 0.5(3) 177.14( 18) -1.0(3) 1.2(3) -0.9(3) -0.2(3) -176.87( 18) 0.4(3) 60.0(2) -59.97(19) -178.74( 17) -60.99( 19) 178.99( 16) 60.22( 18) 179.33(17) 59.31 (19) -59.46( 19) r (0) - CUll I· II.:. --'"-' • ((10) ell"~ ,._f'/ l.l:1! 'Nt21 \;----, l / (.( /I !'IllI I ( ) CIS) I" ."""( / - ,CH,) Figure 14. ORTEP illustration of 14g, with ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of 14g suitable for X-ray diffraction were obtained by seeding an oil of 14g oil with 14a. ------------------ -------------- 238 Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2. All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for C13H13BF6N203S are given in the following tables. Table 35. Crystal data and structure refmement for 14g (Hu56). a = 90°. f) = 96.233(5) 0. y = 90°. Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size Theta range for data collection Index mnges Reflections collected Independent reflections Completeness to theta = 25.00° Absorption correction liu56 C13 H13 B F6N2 03 S 402.12 173(2) K 0.71073 A Monoclinic P2(1)/c a = 7.206(2) A b = 16.671(5) A c = 13.755(4) A 1642.6(9) A 3 4 1.626 Mg/m3 0.278 mm-1 816 0.39 x 0.09 x 0.03 mm3 1.93 to 25.00°. -8<=h<=8, -19<=k<=19, -16<=1<=16 14523 2902 [R(int) = 0.0790] 100.0 % Semi-empirical from equivalents Max. and min. transmission Refinement method Data / restraints / parameters Goodness-of-fit on F2 Final R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole 0.9917 and 0.8993 Full-matrix least-squares on F2 2902/0/287 1.006 R1 = 0.0558, wR2 = 0.1251 R1 = 0.0894, wR2 = 0.1415 0.342 and -0.361 e. A -3 239 Table 36. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2x 103) for 14g. U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. x y z U(eq) S(1) 0(1) 0(2) 0(3) N(1) N(2) B(1) F(1) F(2) F(3) F(4) F(5) F(6) C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(11) C(12) C(13) 1906(1) 2701(4) 2268(4) 33(3) 2125(4) 2408(4) 2431(5) 765(4) 2550(5) 3679(4) 2723(4) 5074(3) 3078(3) 2179(5) 2473(5) 2736(5) 2714(5) 1597(5) 3116(6) 3653(5) 3695(5) 2399(5) 1137(5) 1165(5) 2368(5) 3248(5) 7273(1) 6493(2) 7827(2) 7288(2) 4381(2) 2926(2) 3822(2) 187(2) 1(1) 179(2) 8426(2) 7714(2) 7246(2) 5181(2) 5451(2) 4921(2) 4112(2) 4171(2) 4371(3) 2593(2) 1787(2) 1308(2) 1642(2) 2453(2) 423(2) 7684(2) 2371(1) 2297(2) 1615(2) 2643(2) 4147(2) 4689(2) 4925(3) 3705(2) 4981(2) 3652(2) 3635(2) 3339(2) 4239(2) 4362(3) 5297(3) 6092(3) 5949(3) 3106(3) 2468(3) 4144(2) 3968(3) 4352(2) 4913(3) 5080(3) 4166(3) 3435(3) 27(1) 43(1) 44(1) 41(1) 24(1) 24(1) 24(1) 82(1) 71(1) 72(1) 66(1) 51(1) 54(1) 29(1) 32(1) 33(1) 32(1) 29(1) 36(1) 27(1) 28(1) 25(1) 29(1) 28(1) 34(1) 35(1) Table 37. 8(1)-0(1) 8(1)-0(2) S(1)-0(3) 8(1)-C(13) N(l)-C(1) N(l)-B(1) N(1)-C(5) N(2)-C(11) Bond lengths [A] and angles [0] for 14g. 1.429(3) 1.436(3) 1.439(3) 1.800(4) 1.367(5) 1.418(5) 1.483(4) 1.348(4) N(2)-C(7) N(2)-B(1) B(1)-C(4) F(1)-C(12) F(2)-C(12) F(3)-C(12) F(4)-C(13) F(5)-C(13) F(6)-C(13) C(1)-C(2) C(l)-H(1) C(2)-C(3) C(2)-H(2) C(3)-C(4) C(3)-H(3) C(4)-H(4) C(5)-C(6) C(5)-H(5A) C(5)-H(5B) C(6)-H(6A) C(6)-H(6B) C(6)-H(6C) C(7)-C(8) C(7)-H(7) C(8)-C(9) C(8)-H(8) C(9)-C(10) C(9)-C(12) C(10)-C(11) C(10)-H(10) C(11)-H(11) 0(1 )-S(1 )-0(2) 0(1 )-S(1)-0(3) 0(2)-S(1 )-0(3) 0(1)-S(1)-C(13) 0(2)-S(1)-C(13) 0(3)-S(1)-C(13) C(l)-N(l)-B(1) C(1)-N(1)-C(5) B(1)-N(1)-C(5) C(11)-N(2)-C(7) C(11)-N(2)-B(1) C(7)-N(2)-B(1 ) N(1)-B(1)-C(4) N(1)-B(1)-N(2) C(4)-B(1)-N(2) C(2)-C(1)-N(1) C(2)-C(1)-H(1) N(1)-C(1)-H(1) C(1 )-C(2)-C(3) C(1)-C(2)-H(2) C(3)-C(2)-H(2) C(4)-C(3)-C(2) 1.349(4) 1.528(5) 1.481(5) 1.316(4) 1.319(4) 1.305(4) 1.331(4) 1.338(4) 1.342(4) 1.356(5) 0.97(3) 1.403(6) 0.90(4) 1.363(5) 0.97(4) 0.93(4) 1.513(5) 0.96(3) 0.97(3) 0.93(4) 0.97(4) 0.98(4) 1.367(5) 0.86(3) 1.378(5) 0.91(4) 1.373(5) 1.497(5) 1.370(5) 0.88(3) 0.93(3) 115.30(16) 115.44(17) 115.24(16) 102.74(18) 102.67(17) 102.61(17) 118.7(3) 115.9(3) 125.2(3) 119.4(3) 118.7(3) 121.9(3) 119.8(3) 119.0(3) 121.2(3) 121.8(3) 122(2) 116(2) 121.6(4) 119(2) 120(2) 120.9(3) 240 C(4)-C(3)-H(3) C(2)-C(3)-H(3) C(3)-C(4)-B(1) C(3)-C(4)-H(4) B(1)-C(4)-H(4) N(1)-C(5)-C(6) N(1)-C(5)-H(5A) C(6)-C(5)-H(5A) N(1)-C(5)-H(5B) C(6)-C(5)-H(5B) H(5A)-C(5)-H(5B) C(5)-C(6)-H(6A) C(5)-C(6)-H(6B) H(6A)-C(6)-H(6B) C(5)-C(6)-H(6C) H(6A)-C(6)-H(6C) H(6B)-C(6)-H(6C) N(2)-C(7)-C(8) N(2)-C(7)-H(7) C(8)-C(7)-H(7) C(7)-C(8)-C(9) C(7)-C(8)-H(8) C(9)-C(8)-H(8) C(10)-C(9)-C(8) C(10)-C(9)-C(12) C(8)-C(9)-C(12) C(1l)-C(10)-C(9) C(1l)-C(10)-H(10) C(9)-C(10)-H(10) N(2)-C(11)-C(10) N(2)-C(11)-H(11) C(1O)-C(11)-H(11) F(3)-C(12)-F(1) F(3)-C(12)-F(2) F(1)-C(12)-F(2) F(3)-C(12)-C(9) F(1 )-C(12)-C(9) F(2)-C(12)-C(9) F(4)-C(13)-F(5) F(4)-C(13)-F(6) F(5)-C(13)-F(6) F(4)-C(13)-S(1) F(5)-C(13)-S(1) F(6)-C(13)-S(1) 122(3) 117(3) 117.3(4) 118(2) 124(2) 112.5(3) 108(2) 109(2) 108.5(19) 110.1(19) 108(3) 109(2) 109(2) 112(3) 115(2) 108(3) 105(3) 122.2(3) 117(2) 121(2) 118.2(3) 122(3) 120(3) 119.9(3) 119.9(3) 120.2(3) 119.7(3) 119(2) 121(2) 120.6(3) 115(2) 124(2) 107.2(3) 106.5(3) 104.5(3) 113.7(3) 111.9(3) 112.4(3) 106.9(3) 106.4(3) 106.3(3) 112.5(3) 112.4(3) 111.9(3) 241 Table 38. Anisotropic displacement parameters (A2x 103)for 14g. The anisotropic displacement factor exponent takes the form: _2p2[ h2a*2UIl + ... + 2 h k a* b* U12 ] S(1) 0(1) 0(2) 26(1) 49(2) 42(2) 36(1) 39(2) 63(2) 20(1) 44(2) 29(2) 5(1) -5(1) 21(1) 8(1) 15(1) 11(1) 2(1) 3(1) 3(1) 242 0(3) 23(1) 65(2) 38(2) 8(1) 9(1) 0(1) N(1) 21(2) 31(2) 20(2) 1(1) 2(1) -1(1) N(2) 21(2) 33(2) 16(1) 1(1) 3(1) 1(1) B(1) 16(2) 32(2) 26(2) 0(2) 8(2) -2(2) F(1) 67(2) 53(2) 117(3) -34(2) -32(2) -6(1) F(2) 141(3) 37(1) 37(1) 5(1) 17(2) 3(2) F(3) 89(2) 41(2) 98(2) -18(2) 62(2) ~3(l) F(4) 78(2) 48(2) 70(2) -22(1) 9(2) -2(1) F(5) 29(1) 69(2) 53(2) 11(1) 3(1) -13(1) F(6) 50(2) 89(2) 24(1) 16(1) 1(1) -15(1) C(1) 30(2) 31(2) 28(2) 3(2) 10(2) -1(2) C(2) 30(2) 35(2) 32(2) -8(2) 11(2) -3(2) C(3) 28(2) 48(3) 22(2) -11(2) 7(2) -1(2) C(4) 29(2) 45(2) 22(2) , 2(2) 6(2) 0(2) C(5) 35(2) 34(2) 18(2) 1(2) -1(2) -2(2) C(6) 48(3) 43(3) 19(2) 3(2) 9(2) 0(2) C(7) 25(2) 35(2) 21(2) 2(2) 7(2) -3(2) C(8) 25(2) 39(2) 22(2) -2(2) 9(2) 4(2) C(9) 25(2) 35(2) 14(2) -1(1) 4(1) 1(2) C(10) 31(2) 34(2) 25(2) 3(2) 13(2) -6(2) C(11) 25(2) 34(2) 27(2) 4(2) 15(2) 1(2) C(12) 38(2) 37(2) 27(2) -7(2) 8(2) -7(2) C(13) 33(2) 39(2) 34(2) 5(2) 6(2) -1(2) Table 39. Hydrogen coordinates ( x 104) and isotropic displacement parameters (A2x 103) for 14g. x y z U(eq) H(1) 1950(40) 5540(20) 3810(30) 22(9) H(2) 2510(50) 5980(20) 5410(30) 29(10) H(3) 2950(50) 5160(20) 6740(30) 54(13) H(4) 2930(50) 3780(20) 6490(30) 38(11) H(5A) 480(50) 4460(20) 2880(20) 25(9) H(5B) 1310(40) 3600(20) 3060(20) 18(9) H(6A) 2720(50) 4230(20) 1820(30) 44(12) H(6B) 4240(50) 4090(20) 2720(30) 30(10) H(6C) 3480(50) 4940(20) 2470(30) 39(11) H(7) 4430(50) 2910(20) 3920(20) 24(10) H(8) 4550(60) 1560(30) 3610(30) 60(13) H(10) 300(50) 1350(20) 5170(20) 24(9) H(11) 400(50) 2710(20) 5480(20) 27(9) Table 40. Torsion angles [0] for 14g. C(1)-N(1)-B(1)-C(4) 2.8(5) C(5)-N(1)-B(1)-C(4) -172.2(3) C(1)-N(1)-B(1)-N(2) -178.9(3) C(5)-N(1 )-B(1 )-N(2) 6.2(5) C(11)-N(2)-B(1)-N(1) -121.2(3) C(7)-N(2)-B(1)-N(1) 62.3(4) C(11)-N(2)-B(1)-C(4) 57.1(4) C(7)-N(2)-B(1 )-C(4) -119.4(4) B(1 )-N(1 )-C( 1)-C(2) C(5)-N(1)-C(1)-C(2) N(1)-C( 1)-C(2)-C(3) C(1 )-C(2)-C(3)-C(4) C(2)-C(3)-C(4)-B( 1) N(1 )-B(1 )-C(4)-C(3) N(2)-B(1 )-C(4)-C(3) C(1)-N(1 )-C(5)-C(6) B(1)-N(1 )-C(5)-C(6) C(11)-N(2)-C(7)-C(8) B(1 )-N(2)-C(7)-C(8) N(2)-C(7)-C(8)-C(9) C(7)-C(8)-C(9)-C(10) C(7)-C(8)-C(9)-C(12) C(8)-C(9)-C(1 0)-C(11) C(12)-C(9)-C( 1O)-C( 11) C(7)-N(2)-C(11 )-C(1 0) B(1)-N(2)-C(11)-C(10) C(9)-C(10)-C(11)-N(2) C(1 0)-C(9)-C( 12)-F(3) C(8)-C(9)-C(12)-F(3) C(1 0)-C(9)-C(12)-F(1) C(8)-C(9)-C(12)-F(1) C(10)-C(9)-C(12)-F(2) C(8)-C(9)-C(12)-F(2) 0(1 )-S(1 )-C(13)-F(4) 0(2)-S(1 )-C(13)-F(4) 0(3)-S(1)-C(13)-F(4) O( 1)-S(1 )-C(13)-F(5) 0(2)-S(1 )-C(13)-F(5) 0(3)-S(1 )-C(13)-F(5) 0(1 )-S(1 )-C( 13)-F(6) 0(2)-S(1)-C(13)-F(6) 0(3)-S(1)-C(13)-F(6) -1.6(5) 173.8(3) 0.0(6) 0.3(6) 0.9(5) -2.4(5) 179.3(3) 71.6(4) -113.4(4) 0.3(5) 176.9(3) 0.9(5) -1.4(5) 179.0(3) 0.6(5) -179.8(3) -1.2(5) -177.8(3) 0.7(6) -177.7(3) 1.9(5) 60.7(5) -119.7(4) -56.6(5) 123.0(4) 179.7(3) 59.7(3) -60.1 (3) 59.0(3) -61.0(3) 179.2(3) -60.5(3) 179.5(3) 59.6(3) 243 244 'I \CIHI I • _ , '..... elY) /, ........ ,/" ~7r('(p) (/1' . I (',]11) / ....... , JI rOll 0121 om -1 , 0(3) ~1'l1il/ "., III (,II ,I 1(') Figure 15. ORTEP illustration of 14h, with ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of 14h suitable for X-ray diffraction were obtained by seeding the oil of 14h with crystals of 14a. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2. All non-H atoms were refined with anisotropic thenual parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Brukcr XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for C13HI6BF3N203S are given in the following tables. Table 41. Crystal data and structure refinement for 14h (liu42a). 245 a = 90°. B= 90°. y = 90°. Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 25.00° Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters Goodness-of-fit on F2 Final R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole liu42a Cn H16 B F3 Nz 0 3 S 348.15 173(2) K 0.71073 A Orthorhombic Pbca a = 13.9209(8) A b = 13.1486(8) A c = 17.8275(11) A 3263.2(3) A3 8 1.417 Mg/m3 0.243 mm-1 1440 0.22 x 0.12 x 0.09 mm3 2.28 to 25.00°. -16<=h<=16, -15<=k<=15, -21 <=1<=21 24679 2874 [R(int) = 0.0819] 100.0 % Semi-empirical from equivalents 0.9785 and 0.9486 Full-matrix least-squares on F2 2874/0/272 1.004 Rl = 0.0400, wR2 = 0.0805 Rl = 0.0703, wR2 = 0.0952 0.213 and -0.273 e.A-3 Table 42. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (A2x 103) for 14h. U(eq) is defmed as one third of the trace of the orthogonalized Uij tensor. x y z U(eq) S(1) 2421(1) 7612(1) 1820(1) 29(1) 0(1) 2516(1) 7660(2) 2621(1) 46(1) 0(2) 1899(1) 6762(1) 1539(1) 44(1) 0(3) 3284(1) 7869(1) 1419(1) 44(1) F(l) 1456(1) 8748(1) 873(1) 51(1) F(2) 1986(1) 9562(1) 1831(1) 59(1) F(3) N(1) N(2) B(1) C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(11) C(12) C(13) 772(1) 744(1) 124(1) 679(2) 1229(2) 1639(2) 1598(2) 1137(2) 291(2) 1009(2) -635(2) -1130(2) -868(2) -74(2) 401(2) -1414(3) 1625(2) 8566(1) 939(2) 468(2) 211(2) 690(2) -235(2) -986(2) -803(2) 1962(2) 2817(2) -115(2) 56(2) 849(2) 1432(2) 1230(2) 1076(3) 8672(2) 1939(1) 4339(1) 3043(1) 3756(2) 4983(2) 5091(2) 4527(2) 3864(2) 4338(2) 4298(2) 2842(2) 2191(2) 1719(1) 1927(2) 2582(2) 1016(2) 1609(2) 47(1) 28(1) 27(1) 30(1) 34(1) 37(1) 36(1) 33(1) 32(1) 42(1) 30(1) 30(1) 31(1) 34(1) 33(1) 50(1) 34(1) 246 Table 43. Bond lengths [A] and angles [0] for 14h. S(1)-0(2) S(1)-O(1) S(1)-0(3) S(1)-C(13) F(1)-C(13) F(2)-C(13) F(3)-C(13) N(1)-C(l) N(1)-B(1) N(1)-C(5) N(2)-C(11) N(2)-C(7) N(2)-B(1) B(1)-C(4) C(1)-C(2) C(l)-H(1) C(2)-C(3) C(2)-H(5) C(3)-C(4) C(3)-H(3) C(4)-H(4) C(5)-C(6) C(5)-H(5A) C(5)-H(5B) C(6)-H(6A) C(6)-H(6B) C(6)-H(6C) C(7)-C(8) C(7)-H(7) C(8)-C(9) C(8)-H(8) C(9)-C(1O) C(9)-C(12) 1.4242(18) 1.4350(18) 1.4379(18) 1.820(3) 1.336(3) 1.333(3) 1.334(3) 1.371(3) 1.416(4) 1.486(3) 1.352(3) 1.353(3) 1.526(4) 1.489(4) 1.358(4) 0.93(2) 1.410(4) 0.95(3) 1.367(4) 0.98(2) 0.93(3) 1.505(4) 0.98(3) 0.97(2) 1.02(3) 0.98(3) 1.00(3) 1.370(4) 0.97(3) 1.388(4) 0.95(3) 1.395(4) 1.495(4) C(lO)-C(ll) C(1 O)-H(1 0) C(11)-H(11) C(12)-H( 12A) C(12)-H(12B) C(12)-H(12C) 0(2)-S(1 )-0(1) 0(2)-S(1 )-0(3) 0(1)-S(1)-0(3) 0(2)-S(1)-C(13) 0(1)-S(1)-C(13) 0(3)-S(1)-C(13) C(1)-N(1)-B(1) C(1 )-N(1 )-C(5) B(1)-N(1 )-C(5) C(11)-N(2)-C(7) C(11)-N(2)-B(1) C(7)-N(2)-B(1) N(1)-B(1)-C(4) N(1)-B(1)-N(2) C(4)-B(1)-N(2) C(2)-C(1)-N(1) C(2)-C(1 )-H(1 ) N(1)-C(1)-H(1) C(1)-C(2)-C(3) C(1)-C(2)-H(5) C(3)-C(2)-H(5) C(4)-C(3)-C(2) C(4)-C(3)-H(3) C(2)-C(3)-H(3) C(3)-C(4)-B(1) C(3)-C(4)-H(4) B(1)-C(4)-H(4) N(1)-C(5)-C(6) N(1)-C(5)-H(5A) C(6)-C(5)-H(5A) N(1)-C(5)-H(5B) C(6)-C(5)-H(5B) H(5A)-C(5)-H(5B) C(5)-C(6)-H(6A) C(5)-C(6)-H(6B) H(6A)-C(6)-H(6B) C(5)-C(6)-H(6C) H(6A)-C(6)-H(6C) H(6B)-C(6)-H(6C) N(2)-C(7)-C(8) N(2)-C(7)-H(7) C(8)~C(7)-H(7) C(7)-C(8)-C(9) C(7)-C(8)-H(8) C(9)-C(8)-H(8) C(8)-C(9)-C(10) C(8)-C(9)-C(12) 1.368(4) 0.95(3) 0.96(3) 0.97(4) 0.96(4) 0.82(4) 115.58(12) 115.77(12) 114.03(12) 102.59(12) 103.23(12) 103.06(12) 119.0(2) 115.3(2) 125.7(2) 118.8(2) 121.8(2) 119.3(2) 118.9(2) 119.6(2) 121.5(2) 122.7(3) 121.0(15) 116.4(15) 120.6(3) 119.2(16) 120.2(16) 120.8(3) 120.1(14) 119.0(14) 118.0(3) 119.8(16) 122.1(16) 113.2(2) 106.8(15) 110.7(15) 108.0(14) 111.5(14) 106(2) 110.9(17) 112.3(16) 109(2) 111.0(16) 108(2) 105(2) 121.6(3) 116.8(15) 121.6(15) 120.3(3) 120.3(15) 119.3(15) 117.4(2) 121.6(3) 247 C(10)-C(9)-C(12) C(11)-C(10)-C(9) C(11)-C(10)-H(10) C(9)-C(1 O)-H(1 0) N(2)-C(11)-C(10) N(2)-C(11)-H(11) C(10)-C(11)-H(11) C(9)-C(12)-H(12A) C(9)-C(12)-H(12B) H(12A)-C(12)-H(12B) C(9)-C(12)-H(12C) H(12A)-C(12)-H(12C) H(12B)-C(12)-H(12C) F(2)-C(13)-F(3) F(2)-C(13)-F(1) F(3)-C(13)-F(1 ) F(2)-C(13)-S(1) F(3)-C(13)-S(1) F(1)-C(13)-S(1) 121.0(3) 120.2(3) 116.0(16) 123.7(16) 121.6(3) 115.9(15) 122.5(15) 111(2) 109(2) 107(3) 111 (3) 106(3) 112(4) 107.3(2) 107.0(2) 106.5(2) 112.39(18) 111.73(18) 111.56(18) 248 Table 44. Anisotropic displacement parameters (A2x 103)for 14h. The anisotropic displacement factor exponent takes the form: _2p2[ h2a*2U 11 + ... + 2 h k a* b* Ul2 ] Ul1 U22 U33 U23 UB Ul2 S(1) 28(1) 29(1) 30(1) 0(1) -2(1) 0(1) 0(1) 51(1) 59(1) 29(1) 0(1) -8(1) 13(1) 0(2) 40(1) 33(1) 59(1) -8(1) -6(1) -6(1) 0(3) 29(1) 48(1) 54(1) 13(1) 10(1) 2(1) F(1) 51(1) 62(1) 40(1) 11(1) -9(1) 8(1) F(2) 55(1) 30(1) 92(1) -8(1) -21(1) 3(1) F(3) 32(1) 59(1) 52(1) -7(1) 3(1) 10(1) N(1) 22(1) 35(1) 27(1) 1(1) -1(1) -2(1) N(2) 24(1) 28(1) 29(1) 0(1) 1(1) -3(1) B(1) 20(2) 39(2) 30(2) 4(1) 2(1) -5(1) C(1) 30(2) 44(2) 29(2) -1(1) 0(1) -7(1) C(2) 29(2) 51(2) 31(2) 10(1) -2(1) -3(1) C(3) 27(2) 36(2) 45(2) 8(1) 4(1) 4(1) C(4) 32(2) 37(2) 31(2) -3(1) 1(1) 0(1) C(5) 25(2) 34(2) 37(2) -4(1) 0(1) 0(1) C(6) 35(2) 41(2) 50(2) -1(2) 2(2) -6(1) C(7) 26(2) 30(2) 33(2) -2(1) 4(1) -2(1) C(8) 23(1) 36(2) 32(2) -9(1) -1(1) -3(1) C(9) 29(2) 35(2) 30(2) -4(1) 0(1) 0(1) C(10) 35(2) 35(2) 32(2) 4(1) -1(1) -5(1) C(11) 30(2) 35(2) 33(2) -1(1) -2(1) -9(1) C(12) 54(2) 59(2) 37(2) 4(2) -17(2) -4(2) C(13) 30(2) 35(2) 36(2) -4(1) -4(1) -2(1) 249 Table 45. Hydrogen coordinates ( x 104) and isotropic displacement parameters (A2x 103) for 14h. x y z U(eq) H(1) 1266(17) 1195(18) 5350(14) 29(7) H(3) 1891(17) -1652(18) 4622(13) 30(7) H(4) 1101(18) -1310(19) 3504(14) 38(8) H(5) 1955(18) -372(19) 5552(15) 37(8) H(5A) -93(18) 2011(18) 4796(14) 32(7) H(5B) -161(18) 1989(17) 3922(14) 29(7) H(6A) 670(20) 3500(20) 4291(15) 58(9) H(6B) 1420(20) 2770(20) 3859(16) 49(9) H(6C) 1450(20) 2800(20) 4739(16) 49(9) H(7) -791(18) -680(20) 3169(14) 37(7) H(8) -1663(19) -362(19) 2059(14) 36(8) H(10) 175(18) 1972(19) 1634(14) 38(8) H(11) 957(18) 1610(18) 2740(13) 33(7) H(12A) -990(30) 1330(30) 620(20) 89(13) H(12B) -1880(30) 1600(30) 1120(20) 109(16) H(12C) -1660(30) 560(30) 850(20) 95(16) Table 46. Torsion angles [0] for 14h. C(1)-N(1)-B(1)-C(4) C(5)-N(1 )-B(1)-C(4) C(1)-N(1)-B(1)-N(2) C(5)-N(1)-B(1)-N(2) C(11)-N(2)-B(1)-N(1) C(7)-N(2)-B(1)-N(1) C(11)-N(2)-B(1)-C(4) C(7)-N(2)-B(1)-C(4) B(1)-N(1)-C(I)-C(2) C(5)-N(1 )-C(1)-C(2) N(1)-C(1)-C(2)-C(3) C(1)-C(2)-C(3)-C(4) C(2)-C(3)-C(4)-B(1 ) N(l)-B(1 )-C(4)-C(3) N(2)-B(1)-C(4)-C(3) C(1)-N(1 )-C(5)-C(6) B(1)-N(1)-C(5)-C(6) C(11)-N(2)-C(7)-C(8) B(1)-N(2)-C(7)-C(8) N(2)-C(7)-C(8)-C(9) C(7)-C(8)-C(9)-C(10) C(7)-C(8)-C(9)-C(12) C(8)-C(9)-C(1 0)-C(11) C(12)-C(9)-C(10)-C(II) C(7)-N(2)-C(II)-C(10) B(I)-N(2)-C(11)-C(lO) C(9)-C(10)-C(11)-N(2) 0(2)-S(1 )-C(13)-F(2) 0(1 )-S(1 )-C(13)-F(2) 0(3)-S(1 )-C(13)-F(2) 0.1(4) -176.9(2) 178.8(2) 1.7(4) 63.1(3) -120.6(3) -118.3(3) 58.0(3) -1.1(4) 176.3(2) 1.4(4) -0.7(4) -0.1(4) 0.4(4) -178.2(2) 70.5(3) -112.4(3) -0.7(4) -177.1(2) -0.6(4) 1.6(4) -178.0(3) -1.4(4) 178.2(3) 0.9(4) 177.3(3) 0.2(4) -179.96(19) 59.6(2) -59.4(2) 250 O(2)-S( I)-C( 13)-F(3) O( I )-S( I )-C( 13)-F(3) O(3)-S( l)-C( 13 )-F(3) O(2)-S( l)-C( 13 )-F( I) O( I)-S( I)-C( 13)-F( I) O(3)-S(I )-C(l3)-F(1) 59.4(2) -61.1(2) 179.97(18) -59.7(2) 179.81(18) 60.9(2) ( ~ ') elf))/. ~) Figure 16. ORTEP illustration of 14i, with ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of 14i suitable for X-ray diffraction were obtained by seeding the oil of 14i with crystals of 14a. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2• All non-H atoms were refined with 251 anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for CI4HI9BF3N303S are given in the following tables. Table 47. Crystal data and structure refmement for 14i (liu54). a = 69.556(3t. ~ = 73.803(3t. Y= 73.958(3t. Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 25.00° Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters .r-l" ro ~. ........."'") uooaneSS-OI-Ilt on 1'''''' Final R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole liu54 CI4 HI9 B F3N3 0 3 S 377.19 173(2) K 0.71073 A Tric1inic P-l a = 8.9833(17) A b = 9.9383(19) A c = 10.988(2) A 865.1(3) A3 2 1.448 Mg/m3 0.236 mm- l 392 0.18 x 0.12 x 0.08 mm3 2.02 to 25.00°. -IO<=h<=IO, -l1<=k<=l1, -13<=1<=13 8158 3025 [R(int) = 0.0309] 99.5 % Semi-empirical from equivalents 0.9813 and 0.9587 Full-matrix least-squares on F2 3025/0/302 1.047 Rl = 0.0539, wR2 = 0.1311 Rl = 0.0694, wR2 = 0.1395 0.334 and -0.253 e.A-3 252 Table 48. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (A2X 103) for 14i. U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. x y z U(eq) S(1) 7566(1) 6446(1) 2182(1) 27(1) 0(1) 8599(3) 5620(3) 3098(3) 45(1) 0(2) 6914(3) 5580(3) 1738(3) 40(1) 0(3) 6481(3) 7694(3) 2509(3) 36(1) F(1) 10029(3) 6290(3) 235(3) 52(1) F(2) 8135(3) 8087(3) -286(2) 50(1) F(3) 9622(3) 8168(3) 885(3) 58(1) B(1) 5541(5) 2471(5) 2895(4) 28(1) N(1) 5143(3) 2870(3) 1632(3) 28(1) N(2) 7182(3) 1555(3) 3066(3) 26(1) N(3) 11666(4) -971(3) 3380(3) 29(1) C(1) 3649(5) 3621(4) 1477(5) 35(1) C(2) 2535(5) 3998(4) 2493(5) 38(1) C(3) 2867(5) 3664(4) 3739(5) 37(1) C(4) 4323(5) 2902(5) 4000(4) 36(1) C(5) 6270(5) 2574(5) 442(4) 35(1) C(6) 6032(6) 1294(5) 132(5) 42(1) C(7) 7497(5) 94(4) 3227(4) 32(1) C(8) 8934(5) -781(4) 3371(4) 31(1) C(9) 10201(4) -170(4) 3324(3) 25(1) C(10) 9833(4) 1342(4) 3205(4) 28(1) C(11) 8358(4) 2150(4) 3079(4) 28(1) C(12) 12005(6) -2552(5) 3577(6) 41(1) C(13) 12946(5) -297(5) 3309(5) 36(1) C(14) 8902(5) 7286(4) 687(4) 35(1) Table 49. Bond lengths [A] and angles [0] for 14i. S(1)-0(2) 1.433(3) S(1)-0(3) 1.437(3) S(1)-O(1) 1.439(3) S(1)-C(14) 1.826(4) F(1)-C(14) 1.327(4) F(2)-C(14) 1.328(5) F(3)-C(14) 1.327(5) B(1)-N(1) 1.423(5) B(1)-C(4) 1.489(6) B(1)-N(2) 1.527(5) N(1)-C(1) 1.368(5) N(1)-C(5) 1.478(5) N(2)-C(Il) 1.352(5) N(2)-C(7) 1.357(5) N(3)-C(9) 1.342(4) N(3)-C(13) 1.455(5) N(3)-C(12) 1.464(5) C(1)-C(2) 1.360(6) C(1)-H(1) 0.96(5) C(2)-C(3) 1.389(6) C(2)-H(2) C(3)-C(4) C(3)-H(3) C(4)-H(4) C(5)-C(6) C(5)-H(5A) C(5)-H(5B) C(6)-H(6A) C(6)-H(6B) C(6)-H(6C) C(7)-C(8) C(7)-H(7) C(8)-C(9) C(8)-H(8) C(9)-C(10) C(1O)-C(11) C(1O)-H(10) C(1l)-H(11) C(12)-H(12A) C(12)-H(12B) C(12)-H(12C) C(13)-H(13A) C(13)-H(13B) C(13)-H(13C) 0(2)-S(1 )-0(3) 0(2)-S(1 )-0(1) 0(3)-S(1 )-0(1) 0(2)-S(1)-C(14) 0(3)-S(1)-C(14) 0(1)-S(1)~C(14) N(1)-B(1)-C(4) N(1)-B(1)-N(2) C(4)-B(1)-N(2) C(l)-N(1)-B(1) C(1)-N(1)-C(5) B(1)-N(1)-C(5) C(1l)-N(2)-C(7) C(1l)-N(2)-B(1) C(7)-N(2)-B(1) C(9)-N(3)-C(13) C(9)-N(3)-C(12) C(13)-N(3)-C(12) C(2)-C(1)-N(1) C(2)-C(1)-H(1) N(1)-C(1)-H(1) C(1 )-C(2)-C(3) C(1 )-C(2)-H(2) C(3)-C(2)-H(2) C(4)-C(3)-C(2) C(4)-C(3)-H(3) C(2)-C(3)-H(3) C(3)-C(4)-B(1) C(3)-C(4)-H(4) 0.82(5) 1.370(6) 0.97(4) 0.95(4) 1.508(6) 0.95(5) 0.88(4) 0.91(5) 1.01(5) 1.01(5) 1.358(5) 0.88(4) 1.412(5) 0.92(4) 1.413(5) 1.362(5) 0.95(4) 1.07(3) 0.91(5) 0.97(5) 0.90(5) 0.85(5) 0.97(5) 1.03(5) 115.53(17) 114.92(18) 114.84(18) 102.90(18) 102.73(17) 103.36(18) 118.9(3) 118.0(3) 123.0(4) 118.9(3) 117.0(3) 124.0(3) 117.7(3) 122.0(3) 120.3(3) 120.5(3) 121.2(3) 118.2(3) 122.0(4) 123(3) 115(3) 121.5(4) 121(3) 118(3) 121.0(4) 117(3) 122(3) 117.6(4) 120(3) 253 B(1)-C(4)-H(4) 122(3) N(1)-C(5)-C(6) 112.8(4) N(1)-C(5)-H(5A) 111(3) C(6)-C(5)-H(5A) 106(3) N(1)-C(5)-H(5B) 108(3) C(6)-C(5)-H(5B) 107(3) H(5A)-C(5)-H(5B) 111(4) C(5)-C(6)-H(6A) 115(3) C(5)-C(6)-H(6B) 113(3) H(6A)-C(6)-H(6B) 106(4) C(5)-C(6)-H(6C) 111(3) H(6A)-C(6)-H(6C) 108(4) H(6B)-C(6)-H(6C) 102(4) N(2)-C(7)-C(8) 123.3(4) N(2)-C(7)-H(7) 116(3) C(8)-C(7)-H(7) 120(3) C(7)-C(8)-C(9) 120.0(4) C(7)-C(8)-H(8) 119(2) C(9)-C(8)-H(8) 121(2) N(3)-C(9)-C(8) 122.2(3) N(3)-C(9)-C(10) 122.0(3) C(8)-C(9)-C(10) 115.8(3) C(11)-C(10)-C(9) 121.0(4) C(11)-C(10)-H(10) 119(2) C(9)-C(10)-H(10) 120(2) N(2)-C(11)-C(10) 122.1(3) N(2)-C(11)-H(11) 115.5(18) C(10)-C(11)-H(11) 121.7(18) N(3)-C(12)-H(12A) 110(3) N(3)-C(12)-H(12B) 114(3) H(12A)-C(12)-H(12B) 102(4) N(3)-C(12)-H(12C) 111(3) H(12A)-C(12)-H(12C) 117(4) H(12B)-C(12)-H(12C) 102(4) N(3)-C(13)-H(13A) 107(3) N(3)-C(13)-H(13B) 108(3) H(13A)-C(13)-H(13B) 101(4) N(3)-C(13)-H(13C) 116(3) H(13A)-C(13)-H(13C) 117(4) H(13B)-C(13)-H(13C) 106(4) F(3)-C(14)-F(1) 106.8(3) F(3)-C(14)-F(2) 106.7(3) F(1)-C(14)-F(2) 107.1(3) F(3)-C(14)-S(1) 112.5(3) F(1)-C(14)-S(1) 111.9(3) F(2)-C(14)-S(1) 111.5(3) Symmetry transformations used to generate equivalent atoms: 254 255 Table 50. Anisotropic displacement parameters (A2x 103)for 14i. The anisotropic displacement factor exponent takes the form: _2p2[ h2a*2Ull + ... + 2 h k a* b* U12 ] Ull U22 U33 U23 Ul3 Ul2 S(1) 24(1) 24(1) 30(1) -8(1) -6(1) 2(1) 0(1) 40(2) 52(2) 36(2) -9(1) -16(1) 10(1) 0(2) 44(2) 32(2) 47(2) -10(1) -11(1) -11(1) 0(3) 30(2) 30(2) 41(2) -14(1) 1(1) 1(1) F(1) 38(1) 55(2) 53(2) -27(1) 8(1) 5(1) F(2) 48(2) 51(2) 36(1) 1(1) -7(1) -5(1) F(3) 53(2) 74(2) 62(2) -36(2) 9(1) -36(2) B(1) 20(2) 25(2) 37(3) -8(2) -8(2) -2(2) N(1) 23(2) 25(2) 32(2) -5(1) -6(1) -6(1) N(2) 25(2) 22(2) 30(2) -7(1) -9(1) -1(1) N(3) 24(2) 29(2) 31(2) -8(1) -8(1) 2(1) C(1) 32(2) 26(2) 47(3) -5(2) -20(2) -3(2) C(2) 24(2) 26(2) 60(3) -8(2) -15(2) 1(2) C(3) 29(2) 28(2) 45(3) -11 (2) 1(2) -2(2) C(4) 34(2) 38(2) 34(2) -10(2) -8(2) -2(2) C(5) 35(2) 36(2) 28(2) -4(2) -4(2) -9(2) C(6) 46(3) 36(3) 39(3) -13(2) -6(2) -2(2) C(7) 29(2) 30(2) 39(2) -10(2) -12(2) -6(2) C(8) 31(2) 23(2) 40(2) -11(2) -10(2) 0(2) C(9) 25(2) 26(2) 21(2) -6(2) -5(2) 0(2) C(10) 23(2) 29(2) 31(2) -7(2) -7(2) -4(2) C(11) 27(2) 24(2) 31(2) -7(2) -5(2) -2(2) C(12) 38(3) 28(2) 52(3) -13(2) -12(2) 8(2) C(13) 21(2) 40(3) 43(3) -13(2) -9(2) 4(2) C(14) 29(2) 37(2) 39(2) -19(2) -6(2) 2(2) Table 51. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2x 103) for 14i. x y z U(eq) H(1) 3440(50) 3820(50) 610(50) 48(13) H(2) 1660(60) 4490(50) 2370(40) 48(14) H(3) 2060(50) 3890(50) 4480(40) 43(12) H(4) 4530(50) 2690(50) 4850(40) 42(12) H(5A) 7320(60) 2340(50) 560(40) 49(13) H(5B) 6120(50) 3350(50) -240(40) 29(11) H(6A) 6040(60) 440(60) 810(50) 61(15) H(6B) 6840(50) 1050(50) -640(50) 48(13) H(6C) 5010(60) 1540(60) -190(50) 69(16) H(7) 6720(50) -270(40) 3200(40) 37(12) H(8) 9070(40) -1750(40) 3450(40) 28(10) H(10) 10600(40) 1790(40) 3280(40) 25(10) H(11) 8110(40) 3320(40) 2830(30) 16(8) H(i2A) 11480(60) -3010(60) 4380(50) 60(16) H(12B) 11610(50) -2830(50) 2980(50) 51(14) H(12C) 13050(60) -2890(50) 3380(50) 54(14) H(13A) 13810(60) -890(50) 3140(40) 44(13) H(13B) 13030(50) 520(60) 2500(50) 57(14) H(13C) 12820(50) 140(50) 4070(50) 57(14) 256 Table 52. Torsion angles [0] for 14i. C(4)-B(1)-N(1)-C(1) N(2)-B(1)-N(1)-C(1) C(4)-B(1)-N(1 )-C(5) N(2)-B(1)-N(1)-C(5) N(1)-B(1)-N(2)-C(1l) C(4)-B(1)-N(2)-C(11) N(1)-B(1)-N(2)-C(7) C(4)-B(1 )-N(2)-C(7) B(1 )-N(1 )-C(1 )-C(2) C(5)-N(1 )-C(1 )-C(2) N(1)-C(l)-C(2)-C(3) C(1 )-C(2)-C(3)-C(4) C(2)-C(3)-C(4)-B(1) N(l)-B(1)-C(4)-C(3) N(2)-B(1)-C(4)-C(3) C(l)-N(1)-C(5)-C(6) B(1)-N(1)-C(5)-C(6) C(11)-N(2)-C(7)-C(8) B(l)-N(2)-C(7)-C(8) N(2)-C(7)-C(8)-C(9) C(13)-N(3)-C(9)-C(8) C(12)-N(3)-C(9)-C(8) C(13)-N(3)-C(9)-C(10) C(12)-N(3 )-C(9)-C(1 0) C(7)-C(8)-C(9)-N(3) C(7)-C(8)-C(9)-C(10) N(3)-C(9)-C(10)-C(11) C(8)-C(9)-C(10)-C(11) C(7)-N(2)-C(11)-C(1 0) B(1)-N(2)-C(1l)-C(10) C(9)-C(10)-C(1l)-N(2) 0(2)-S(1)-C(14)-F(3) 0(3)-S(1)-C(14)-F(3) 0(1 )-S(1)-C(14)-F(3) 0(2)-S(1 )-C(14)-F(1) 0(3)-S(1)-C(14)-F(1) 0(1)-S(l)-C(14)-F(1) 0(2)-S(1 )-C(14)-F(2) 0(3)-S(1 )-C(14)-F(2) 0(1 )-S(1)-C(14)-F(2) Symmetry transfonnations used to generate equivalent atoms: -0.9(5) 176.4(3) 176.7(4) -6.0(5) 102.9(4) -79.9(5) -77.8(5) 99.4(5) 0.1(6) -177.7(4) 1.3(6) -1.9(6) 1.0(6) 0.3(6) -176.8(4) -79.5(5) 102.9(5) -1.3(6) 179.3(4) -1.7(6) 179.1(4) -3.9(6) -0.4(5) 176.6(4) -175.8(4) 3.8(6) 176.4(4) -3.1(5) 2.1(6) -178.6(4) 0.2(6) 179.1(3) 58.7(3) -61.0(3) -60.7(3) 179.0(3) 59.2(3) 59.2(3) -61.1(3) 179.1(3) A.2.6 Supplementai information/or Chapter II, section 2.6 Compound 16. A solution ofallyltriphenyltin (24.45 g, 62.5 mmol in 110 mL CH2Ch) was cooled to -78°C, to which was added dropwise a solution ofBCh (lM in 257 hexanes; 62.5 mL, 62.5 mmol). The reaction was stirred at -78 DC for 4 h, whereupon allylbenzylamine (9.19 g, 62.5 mmol) was added dropwise to the reaction flask. After 20 minutes, NEt3 was added dropwise and the reaction was allowed to warm to rt. After 12 h of stirring, approximately one-half of the solvent was removed under vacuum, and 150 mL pentane was added to the reaction flask. The reaction mixture was passed through a medium-porosity frit, and the filtrate was concentrated under reduced pressure. Vacuum distillation (91 DC, 100 mT) provided 16 as a clear, colorless liquid (6.73g, 46%). IH NMR (600 MHz, CD2Ch): () 7.35-7.45 (m, 5H), 6.15 (m, IH), 5.93 (m, IH), 5.1-5.4 (m, 4H), 4.5-4.6 (app br d, 2H), 3.8-3.95 (m, 2H), 2.28 (m, 2H). llB NMR (192.5 MHz, CD2Ch): () 38.6. Compound 17. In a glove box, a solution ofGrubbs 1st generation catalyst (0.169 g, 0.21 mmol in 20 mL CH2Ch) was added to a stirring solution ofaminoborane 16 (9.6 g, 41.1 mmol in 280 mL CH2Ch). The reaction was stirred at room temperature for 2 h, after which the solvent was removed under vacuum. The desired product was purified by vacuum distillation (bp 82°C at 100 mT) to furnish 17 as a clear, colorless liquid (7.66 g, 91%). IH NMR (600 MHz, CD2Ch): () 7.2-7.4 (m, 5H), 5.75 (br, IH), 5.55 (m, IH), 4.45 (s, 2H), 3.58 (br m, 2H), 1.79 (br m, 2H). llB NMR (192.5 MHz, CD2Ch): () 38.0. Compound 15. In a glovebox, a Schlenk flask was charged with 17 (7.66 g, 37.3 mmol), Pd/C (10 wt%; 7.93 g, 7.46 mmol), and cyclohexene (120 mL). The flask was sealed, then heated to 80 DC for 24 h. The solvent was removed under reduced pressure, after which vacuum distillation provided 15 as a clear, colorless liquid (3.60 g, 47% yield). 258 1 1 3H NMR (600 MHz, CD2C 2): 67.60 (br, IH), 7.2-7.35 (m, 6H), 6.72 (d, JHH = 11.2 Hz, IH), 6.35 (app t, 3JHH = 6.3 Hz, IH), 5.10 (s, 2H). 13C NMR (75 MHz, CD2Ch): 116145.3, 139.5, 139.0, 129.2, 129 (br), 128.1, 127.8, 111.7,56.4. B NMR (192.5 MHz, Compound 18 was observed in the liB NMR (6 29 ppm) of 15 as a minor peak. Compound 18: IH NMR (600 MHz, CD2Ch): 67.58 (dd, 3JHH = 6.1 Hz, 4.7 Hz, IH), 7.05-7.25 (m, 6H) 6.45 (d, 3JHH = 11.4 Hz, IH), 6.02 (app t, 3JHH = 6.1 Hz, IH), 4.82 (s,2H). Compound 19. A vial was charged with a solution of 15 (0.100 g, 0.491 mmol in 3 mL THF) and cooled to -20 cC. To this stirring solution phenylmagnesium bromide (1.8 M solution in BU20; 0.3 mL, 0.54 mmol) was added dropwise. Then the reaction was allowed to warm to room temperature and stirred for 10 h. The solvent was then removed under reduced pressure, and the remaining crude material was subjected to silica gel chromatography using hexane/CH2Ch as eluent. Pure 19 was obtained as a white, crystalline solid (0.085 g, 71 %). IH NMR (600 MHz, CD2Ch): 67.66 (dd, 3JHH = 10.9,6.5 Hz, IH), 7.48 (d, 3JHH = 4.7 Hz, 2H), 7.2-7.4 (m, 7H), 7.05 (d, 3JHH = 6.8 Hz, 2H), 6.87 (d, 3JHH = 10.6 Hz, IH), 6.40 (app t, 3JHH = 6.5 Hz, IH), 5.08 (s, 2H). 13C NMR (125 MHz, CD2Ch): 6 143, 142 11(br), 139, 138, 133, 132 (br), 129, 128, 127.5, 127, 126, 112,57. B NMR (192.5 MHz, 259 Compound 20. To a stirring solution of 15 (0.150 g, 0.737 mmol in 4 mL THF) at -20°C was added phenylethynylmagnesium bromide (0.8 M solution in THF; 0.97 mL, 0.774 mmol). The solution was allowed to warm to room temperature and stirred for 6 h. Approximately one-half of the solvent was removed, and the remaining mixture was passed through an acrodisc. This material was then subjected to silica gel chromatography using a mixture pentane/CH2Ch (10:1) as eluent to afford 20 as a white, crystalline solid (0.145 g, 73%). IH NMR (300 MHz, CD2Clz): 6 7.69 (dd, 3JHH = 10.8,6.8 Hz, IH), 7.56 (dd, 3JHH = 5.6, 4.2 Hz, 2H), 7.4-7.3 (m, 9H), 7.02 (d, 3JHH = 10.9 Hz, IH), 6.43 (app t, 3JHH 6 13= .8 Hz, IH), 5.31 (s,2H). C NMR (125 MHz, CD2Ch): 6 143.6, 140.0, 139.4, 132.3, 132 (br), 129.2, 129.0, 128.9, 128.11, 128.05, 124.2, 112.5, 107.5,59.0. llB NMR (192.5 MHz, CD2Clz): 627.0. Compound 21. In a glove box, a vial was charged with a solution of 15 (0.150 g, 0.737 mmol in 3 mL THF) and cooled to -20°C. To this solution was added BuLi (1.6 M in hexane; 0.51 mL, 0.81 mmol), and the solution was allowed to warm to room temperature. After stirring for 8 h, approximately 75% ofthe solvent was removed. The crude material was subjected to silica gel chromatography using pentane as eluent, providing pure 21 as a clear, colorless liquid (0.064 g, 42%). 1 3H NMR (600 MHz, CD2Ch): 6 7.55 (dd, JHH = 11.7,6.3 Hz, IH), 7.1-7.4 (m, 6H), 6.78 (d, 3JHH = 10.9 Hz, IH), 6.23 (app t, 3JHH = 6.3 Hz, IH), 1.55 (m, 2H), 1.48 260 3 11(m,2H), 1.16 (m, 2H), 0.88 (t, JHH = 7.0 Hz, 3H). B NMR (96.3 MHz, CD2Ch): b 39.1. Compound 22. To a solution of 15 (0.030 g, 0.147 mmol in 1 mL CD2Ch) at- 20 °C was added solid NaOMe (0.008 g, 0.15 mmol). The solution was kept at -20 °C, with occasional stirring, for 6h, whereupon it was warmed to rt. The mixture was then passed through an acrodisc. 1H NMR indicated greater than 90% conversion to 22, and this solution was used directly for the competition bromination experiment with substrate 15. Compound 23. To a stirred solution of 15 (0.150 g, 0.737 mmol in 3 mL THF) was added dropwise a solution of LiHBEt3 (l.0 M in THF; 0.81 mL, 0.81 mmol) at -20 °C. The reaction mixture was allowed to stand at -20°C, with occasional stirring, for 1 h, and then it was warmed to room temperature and stirred for 12 h. Approximately half the solvent was removed, and 5 mL pentane was added. The mixture was then passed through an acrodisc and concentrated under reduced pressure. The crude material was purified by silica gel chromatography using pentane as eluent to furnish 22 as a clear, colorless liquid (0.110 g, 88%). 1 3H NMR (600 MHz, CD2C12): b 7.62 (dd, JHH = 10.2,6.7 Hz, IH), 7.2-7.4 (m, 3 36H) 6.91 (d, JHH = 11.2 Hz, IH), 6.43 (app t, JHH = 6.8 Hz, IH), 5.02 (s, 2H), 5 (br). 13 ~C NMR (75 MHz, CD2Ch): u 143.1, 138.9, 129.2, 128.1, 127.8, 112.8,61.9, C3 not observed. lIB NMR (192.5 MHz, CD2C12): b 33.6 (d, i JBH = 122 Hz). Competition experiment. Compound 15 and a second 1,2-azaborine substrate 261 (19,21,22, or 23) were added to an NMR tube in equimolar amounts. Solvent (1 mL CDzClz) was added to the tube, followed by hexamethylbenzene (approximately 2 mg). An initial IH NMR established the relative ratios of substrates to hexamethylbenzene. The tube was then cooled to -20°C, whereupon 15 fA-L of a 10 vol% Brz solution in CDzClz was added to the tube. The tube was kept at -20°C for 1 h with periodic shaking. The tube was then warmed to rt and a IH NMR spectrum was taken. Integration versus hexamethylbenzene was used to determine the extent of reaction for each substrate, which was compared to the initial spectrum. 15 versus 19: IH NMR indicated 38% of 19 had reacted, while 7% of 15 had reacted; the relative reactivity of 19 to 15 was calculated from these values to be 5.4 to 1. 15 versus 21: IH NMR indicated 28% of21 had been reacted, while 15% of 15 had reacted; the relative reactivity of21 to 15 was calculated from these values to be 1.9 to 1. 15 versus 22: IH NMR indicated 35% of 22 had reacted, while 17% of 15 had reacted; the relative reactivity of22 to 15 was calculated from these values to be 2.1 to 1. 15 versus 23: 1H NMR indicated 21 % of 23 had reacted, while 19% of 15 had reacted; the relative reactivity of23 to 15 was calculated from these values to be 1.1 to 1. 262 ( ,j 02 I l) q(' 03 ~ ) Figure 17. ORTEP illustration of7, with ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of7 suitable for X-ray diffraction were obtained by slow evaporation of an Et20 solution of 7. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71 073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2. All non-H atoms were refined with anisotropic thennal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for C9H 14BN03 are given in the following tables. Table 53. Crystal data and structure refinement for 7 (liu II). a = 90°. f3 = 93.584(2)°. Y= 90°. Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 27.00° Absorption correction Max. and min. transmission Refinement method Data 1restraints 1parameters Goodness-of-fit on F2 Final R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole 263 liu11 C9 H14 B N 0 3 195.02 173(2) K 0.71073 A Monoclinic P2(1)/c a = 8.0468(12) A b = 8.2968(13) A c = 15.361(2) A 1023.5(3) A3 4 1.266 Mg/m3 0.092 mm-1 416 0.39 x 0.32 x 0.26 mm3 2.54 to 27.00°. -10<=h<=10, -10<=k<=10, -19<=1<=19 9259 2216 [R(int) = 0.0276] 98.9% Semi-empirical from equivalents 0.9764 and 0.9649 Full-matrix least-squares on F2 221610/183 1.001 R1 = 0.0376, wR2 = 0.1046 R1 = 0.0445, wR2 = 0.1125 0.245 and -0.160 e.A-3 Table 54. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (A2X 103) for 7. U(eq) is defmed as one third of the trace of the orthogonalized Uij tensor. x y z U(eq) 0(1) 6063(1) 1999(1) 5561(1) 31(1) 0(2) 6803(1) -947(1) 6266(1) 43(1) 0(3) 8327(1) -1599(1) 5148(1) 33(1) N(l) 5792(1) 3738(1) 6793(1) 24(1) B(1) 6848(2) 2805(2) 6265(1) 26(1) C(1) 6445(2) 4598(2) 7494(1) 30(1) C(2) 8099(2) 4626(2) 7723(1) 36(1) C(3) 9225(2) 3747(2) 7237(1) 38(1) C(4) 8698(2) 2850(2) 6529(1) 34(1) 264 C(5) 3972(2) 3846(2) 6610(1) 29(1) C(6) 3446(2) 5473(2) 6258(1) 49(1) C(7) 7005(2) 925(2) 5082(1) 31(1) C(8) 7342(1) -623(1) 5582(1) 28(1) C(9) 8660(2) -3143(2) 5560(1) 42(1) Table 55. Bond lengths [A] and angles [0] for 7. O(1)-B(1) 1.3894(15) 0(1)-C(7) 1.4076(14) O(2)-C(8) 1.1933(15) O(3)-C(8) 1.3392(14) O(3)-C(9) 1.4468(16) N(1)-C(l) 1.3696(15) N(1)-B(1) 1.4359(17) N(1)-C(5) 1.4764(15) B(1)-C(4) 1.5183(19) C(1)-C(2) 1.3552(18) C(l)-H(1) 0.973(16) C(2)-C(3) 1.413(2) C(2)-H(2) 0.971(16) C(3)-C(4) 1.363(2) C(3)-H(3) 0.963(16) C(4)-H(4) 0.952(16) C(5)-C(6) 1.5051(19) C(5)-H(5A) 0.933(16) C(5)-H(5B) 0.983(14) C(6)-H(6A) 0.99(2) C(6)-H(6B) 0.959(19) C(6)-H(6C) 0.923(19) C(7)-C(8) 1.5111(17) C(7)-H(7A) 0.970(15) C(7)-H(7B) 0.985(14) C(9)-H(9A) 0.94(2) C(9)-H(9B) 0.973(18) C(9)-H(9C) 1.006(19) B(1)-0(1)-C(7) 118.57(9) C(8)-O(3)-C(9) 114.69(10) C(1)-N(1)-B(1) 120.87(10) C(1)-N(1)-C(5) 116.40(10) B(1)-N(1)-C(5) 122.72(10) O(1)-B(1)-N(1) 116.23(10) O(1)-B(1)-C(4) 127.60(11) N(1)-B(1)-C(4) 116.15(11) C(2)-C(1)-N(1) 122.37(12) C(2)-C(1)-H(1) 121.8(8) N(1)-C(1)-H(1) 115.8(8) C(1)-C(2)-C(3) 120.37(12) C(1)-C(2)-H(2) 119.6(9) C(3)-C(2)-H(2) 119.9(9) C(4)-C(3)-C(2) 121.70(12) C(4)-C(3)-H(3) 118.8(9) C(2)-C(3)-H(3) 119.5(9) C(3)-C(4)-B(1) 118.54(12) C(3)-C(4)-H(4) 117.7(9) B(1)-C(4)-H(4) 123.7(9) N(1)-C(5)-C(6) 112.10(11) N(1)-C(5)-H(5A) 108.1(9) C(6)-C(5)-H(5A) 111.1(9) N(1)-C(5)-H(5B) 107.8(8) C(6)-C(5)-H(5B) 111.9(8) H(5A)-C(5)-H(5B) 105.6(12) C(5)-C(6)-H(6A) 112.9(12) C(5)-C(6)-H(6B) 111.3(11) H(6A)-C(6)-H(6B) 109.1(16) C(5)-C(6)-H(6C) 109.5(11) H(6A)-C(6)-H(6C) 105.7(16) H(6B)-C(6)-H(6C) 107.9(15) 0(1)-C(7)-C(8) 110.97(10) 0(1)-C(7)-H(7A) 109.0(9) C(8)-C(7)-H(7A) 108.2(9) 0(1)-C(7)-H(7B) 111.8(8) C(8)-C(7)-H(7B) 109.2(8) H(7A)-C(7)-H(7B) 107.6(12) 0(2)-C(8)-0(3) 124.09(11) 0(2)-C(8)-C(7) 125.15(11) 0(3)-C(8)-C(7) 110.76(10) 0(3)-C(9)-H(9A) 109.2(11) 0(3)-C(9)-H(9B) 110.6(10) H(9A)-C(9)-H(9B) 110.8(16) 0(3)-C(9)-H(9C) 102.5(10) H(9A)-C(9)-H(9C) 111.1(15) H(9B)-C(9)-H(9C) 112.4(15) Symmetry transfonnations used to generate equivalent atoms: Table 56. Anisotropic displacement parameters (A2X 103)for 7. The anisotropic displacement factor exponent takes the fonn: _2p2[ h2a*2U 11 + ... + 2 h k a* b* U12] Ull U22 U33 U23 UB U12 0(1) 33(1) 31(1) 28(1) -4(1) 2(1) 10(1) 0(2) 54(1) 43(1) 33(1) 7(1) 17(1) 13(1) 0(3) 36(1) 28(1) 35(1) -1(1) 9(1) 7(1) N(1) 24(1) 24(1) 25(1) 1(1) 3(1) 0(1) B(1) 30(1) 24(1) 26(1) 5(1) 4(1) 5(1) C(1) 34(1) 28(1) 28(1) -1(1) 5(1) -2(1) C(2) 36(1) 40(1) 31(1) -1(1) 0(1) -10(1) C(3) 26(1) 48(1) 38(1) 9(1) -1(1) -4(1) C(4) 28(1) 39(1) 35(1) 7(1) 6(1) 9(1) C(5) 24(1) 34(1) 28(1) -2(1) 4(1) 3(1) C(6) 43(1) 40(1) 63(1) 1(1) -11(1) 14(1) C(7) 35(1) 32(1) 25(1) -2(1) 7(1) 8(1) C(8) 28(1) 30(1) 26(1) -4(1) 3(1) 3(1) C(9) 48(1) 30(1) 47(1) 2(1) 5(1) 11(1) . 265 266 Table 57. Hydrogen coordinates ( x 104) and isotropic displacement parameters (A2X 103) for 7. x Y z U(eq) H(J) 5644( J8) 5172(18) 7827(9) 37(4) 1-1(2) 8514(19) 5293( 19) 8208( I0) 42(4) H(3) 10400(20) 3775(18) 7408( I0) 43(4) H(4) 9520(20) 2291 (\8) 6226( 10) 38(4) H(5A) 3462( 18) 3616(17) 7125(10) 34(4) 1-1(58) 3637(17) 2971 (16) 6204(9) 30(3) 1-1(6A) 3790(20) 6360(20) 6653(13) 70(6) H(68) 2260(20) 5520(20) 6133(11) 62(5) H(6C) 3950(20) 5670(20) 5746(12) 51 (5) H(7A) 6383( 18) 663( (7) 4539( 10) 37(4) H(78) 8072( 18) 1403(16) 4934(9) 29(3) H(9A) 7640(30) -3680(20) 5626(13) 69(6) H(9B) 9270(20) -3000(20) 6122(12) 51(5) H(9C) 9340(20) -3710(20) 5125(12) 58(5) l i (I ['1 Figure 18. ORTEP illustration of 6h, with ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of 6h suitable for X-ray diffraction were obtained by slow evaporation of an Et20 solution of 6h. Diffraction intensity data were collected with a Bruker Smart Apex CCD difffactorneicl ai j 73(2) K Llsing ivloKa - radiaiion (0.7 i 073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and 267 refined by full matrix least-squares procedures on F2• All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for CIsH I9BNP are given in the following tables. Table 57. Crystal data and structure refinement for 6h (liuS). a = 90°. ~ = 90°. y = 90°. Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 27.00° Absorption correction Max. and min. transmission Refinement method Data 1restraints 1parameters Goodness-of-fit on F2 Final R indices [I>2sigma(I)] R indices (all data) liu8 CIS HI9B N P 291.12 173(2) K 0.71073 A Orthorhombic P2(1 )2(1 )2(1) a = 8.9841(6) A b = 10.1554(7) A c = 17.6058(12) A 1606.30(19) A3 4 1.204 Mg/m3 0.163 mm- 1 616 0.32 x 0.28 x 0.18 mm3 2.31 to 27.00°. -11 <=h<=10, -12<=k<=12, -21 <=1<=22 14708 3511 [R(int) = 0.0203] 99.8 % Semi-empirical from equivalents 0.9712 and 0.9497 Full-matrix least-squares on F2 3511/0/266 1.042 Rl = 0.0301, wR2 = 0.0749 Rl = 0.0318, wR2 = 0.0763 Absolute structure parameter Largest diff. peak and hole 0.00(8) 0.241 and -0.116 e.A-3 268 Table 58. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2x 103) for 6h. V(eq) is defmed as one third of the trace of the orthogonalized Vij tensor. x y z V(eq) P(1) B(1) N(1) C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(11) C(12) C(13) C(14) C(15) C(16) C(17) C(18) 2509(1) 1221(2) -47(1) 1342(2) 290(2) -905(2) -1043(2) -400(2) -1432(2) 3945(2) 3629(2) 4663(2) 6058(2) 6394(2) 5341(2) 3513(2) 4388(2) 5113(2) 4966(2) 4109(2) 3405(2) 4049(1) 5533(2) 5818(1) 6349(2) 7288(2) 7505(2) 6780(1) 5083(2) 3943(2) 4178(1) 3622(2) 3630(2) 4171(2) 4729(2) 4742(2) 4514(1) 3554(2) 3814(2) 5030(2) 5995(2) 5742(2) 8332(1) 8577(1) 8106(1) 9289(1) 9439(1) 8941(1) 8298(1) 7400(1) 7548(1) 9069(1) 9774(1) 10353(1) 10240(1) 9546(1) 8965(1) 7464(1) 7111(1) 6433(1) 6087(1) 6428(1) 7116(1) 27(1) 28(1) 27(1) 35(1) 41(1) 38(1) 33(1) 32(1) 48(1) 27(1) 40(1) 44(1) 40(1) 36(1) 31(1) 28(1) 36(1) 46(1) 46(1) 42(1) 34(1) Table 59. Bond lengths [A] and angles [0] for 6h. P(1)-C(7) P(1)-C(13) P(1)-B(1) B(1)-N(1) B(1)-C(1) N(1)-C(4) N(1)-C(5) C(1)-C(2) C(1)-H(1) C(2)-C(3) C(2)-H(2) C(3)-C(4) C(3)-H(3) C(4)-H(4) C(5)-C(6) C(5)-H(5A) C(5)-H(5B) C(6)-H(6A) C(6)-H(6B) 1.8342(14) 1.8360(15) 1.9481(17) 1.439(2) 1.506(2) 1.3670(19) 1.4834(18) 1.369(2) 0.911(18) 1.403(3) 0.93(2) 1.357(2) 0.964(18) 1.002(18) 1.506(2) 0.965(19) 0.943(18) 1.09(3) 0.99(2) C(6)-H(6C) C(7)-C(12) C(7)-C(8) C(8)-C(9) C(8)-H(8) C(9)-C(10) C(9)-H(9) C(1O)-C(1l) C(1O)-H(10) C(11)-C(12) C(ll)-H(1l) C(12)-H(12) C(13)-C(18) C(13)-C(14) C(14)-C(15) C(14)-H(14) C(15)-C(16) C(15)-H(15) C(16)-C(17) C(16)-H(16) C( 17)-C(18) C(17)-H(17) C(18)-H(18) C(7)-P(1)-C(13) C(7)-P(1)-B(1 ) C(13)-P(1)-B(1) N(1)-B(l)-C(1) N(1)-B(1)-P(1) C(1 )-B(1 )-P(1 ) C(4)-N(1)-B(1) C(4)-N(1)-C(5) B(1)-N(1)-C(5) C(2)-C( 1)-B(1 ) C(2)-C(1)-H(1) B(l)-C(1)-H(1) C(1)-C(2)-C(3) C(l)-C(2)-H(2) C(3)-C(2)-H(2) C(4)-C(3)-C(2) C(4)-C(3)-H(3) C(2)-C(3)-H(3) C(3)-C(4)-N(1) C(3)-C(4)-H(4) N(1)-C(4)-H(4) N(1)-C(5)-C(6) N(1 )-C(5)-H(5A) C(6)-C(5)-H(5A) N(1)-C(5)-H(5B) C(6)-C(5)-H(5B) H(5A)-C(5)-H(5B) C(5)-C(6)-H(6A) C(5)-C(6)-H(6B) H(6A)-C(6)-H(6B) 0.85(2) 1.391(2) 1.392(2) 1.380(2) 0.924(19) 1.383(3) 0.97(2) 1.380(2) 0.954(19) 1.394(2) 0.97(2) 0.952(16) 1.393(2) 1.398(2) 1.385(2) 0.973(18) 1.384(3) 0.94(2) 1.384(3) 0.95(2) 1.390(2) 0.93(2) 0.940(17) 103.02(6) 101.88(7) 106.10(7) 115.20(14) 119.90(11) 124.53(12) 121.30(12) 115.28(13) 123.40(12) 119.67(15) 119.1(11) 121.2(11) 121.09(14) 119.8(12) 119.1(12) 120.39(15) 117.5(10) 122.1(10) 122.34(16) 122.6(10) 115.1(11) 111.91(13) 109.1(11) 108.7(11) 109.3(11) 111.8(11) 105.8(15) 107.4(14) 108.8(12) 109.5(19) 269 270 C(5)-C(6)-H(6C) 111.6(16) H(6A)-C(6)-H(6C) 114(2) H(6B)-C(6)-H(6C) 105.4(19) C(12)-C(7)-C(8) 117.91(14) C(12)-C(7)-P(1) 124.76(11) C(8)-C(7)-P(1) 117.28(11) C(9)-C(8)-C(7) 121.29(15) C(9)-C(8)-H(8) 119.0(11) C(7)-C(8)-H(8) 119.7(11) C(8)-C(9)-C(10) 120.37(15) C(8)-C(9)-H(9) 119.2(12) C(10)-C(9)-H(9) 120.4(12) C(11)-C(10)-C(9) 119.30(15) C(11)-C(10)-H(10) 121.9(11) C(9)-C(10)-H(10) 118.8(11) C(10)-C(11)-C(12) 120.36(15) C(10)-C(11)-H(11) 121.2(11) C(12)-C(11)-H(11) 118.4(11) C(7)-C(12)-C(11) 120.75(14) C(7)-C(12)-H(12) 116.3(10) C(11)-C(12)-H(12) 122.9(10) C(18)-C(13)-C(14) 117.89(14) C(18)-C(13)-P(1) 124.20(11) C(14)-C(13)-P(1) 117.84(11) C(15)-C(14)-C(13) 120.97(16) C(15)-C(14)-H(14) 118.9(10) C(13)-C(14)-H(14) 120.1(10) C(14)-C(15)-C(16) 120.35(16) C(14)-C(15)-H(15) 117.0(14) C(16)-C(15)-H(15) 122.6(14) C(15)-C(16)-C(17) 119.57(16) C(15)-C(16)-H(16) 119.8(12) C(17)-C(16)-H(16) 120.6(12) C(16)-C(17)-C(18) 120.05(17) C(16)-C(17)-H(17) 120.1(12) C(18)-C(17)-H(17) 119.8(12) C(17)-C(18)-C(13) 121.15(15) C(17)-C(18)-H(18) 117.2(10) C(13)-C(18)-H(18) 121.7(10) Symmetry transfonnations used to generate equivalent atoms: Table 60. Anisotropic displacement parameters (A2x 103)for 6h. The anisotropic displacement factor exponent takes the fonn: _2p2[ h2a*2U11 + .. , + 2 h k a* b* Ul2] P(l) B(1) N(1) C(1) C(2) C(3) C(4) 27(1) 30(1) 29(1) 42(1) 60(1) 46(1) 33(1) 30(1) 28(1) 28(1) 37(1) 34(1) 29(1) 32(1) 25(1) 25(1) 25(1) 27(1) 29(1) 39(1) 35(1) -un -\.-/ 0(1) 0(1) -3(1) -8(1) 1(1) 6(1) -1(1) 3(1) 4(1) -2(1) 11(1) 15(1) 8(1) 0(1) -3(1) -1(1) -3(1) -4(1) 5(1) 3(1) 271 C(5) 33(1) 38(1) 26(1) -3(1) -2(1) 3(1) C(6) 35(1) 60(1) 49(1) -20(1) 8(1) -12(1) C(7) 28(1) 26(1) 28(1) -1(1) -2(1) 3(1) C(8) 35(1) 49(1) 35(1) 7(1) -1(1) -9(1) C(9) 50(1) 56(1) 28(1) 10(1) -4(1) -6(1) C(10) 39(1) 48(1) 33(1) -2(1) -10(1) 4(1) C(11) 31(1) 41(1) 37(1) -3(1) -2(1) -2(1) C(12) 33(1) 32(1) 29(1) 0(1) 1(1) -1(1) C(13) 24(1) 36(1) 24(1) -4(1) -2(1) -2(1) C(14) 32(1) 44(1) 32(1) -8(1) -5(1) 5(1) C(15) 33(1) 71(1) 35(1) -17(1) 2(1) 6(1) C(16) 35(1) 75(1) 29(1) -8(1) 5(1) -15(1) C(17) 42(1) 49(1) 36(1) 5(1) 0(1) -14(1) C(18) 33(1) 34(1) 35(1) -3(1) 3(1) -4(1) Table 61. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2x 103) for 6h. x y z U(eq) H(1) 2130(20) 6261(18) 9609(10) 40(5) H(2) 380(20) 7815(19) 9872(11) 45(5) H(3) -1647(19) 8172(17) 9035(9) 32(4) H(4) -1870(20) 6915(18) 7926(10) 42(5) H(5A) 510(20) 4748(19) 7183(10) 42(5) H(5B) -794(19) 5670(18) 7037(10) 40(5) H(6A) -850(30) 3260(20) 7927(14) 84(8) H(6B) -1650(20) 3500(20) 7059(12) 55(6) H(6C) -2270(20) 4200(20) 7714(12) 61(6) H(8) 2720(20) 3221(18) 9854(10) 45(5) H(9) 4400(20) 3240(20) 10841(11) 51(6) H(10) 6740(20) 4185(19) 10653(10) 42(5) H(11) 7350(20) 5148(18) 9456(10) 40(4) H(12) 5519(18) 5138(16) 8484(9) 29(4) H(14) 4493(19) 2687(18) 7340(9) 35(4) H(15) 5700(30) 3130(20) 6227(13) 65(7) H(16) 5490(20) 5210(20) 5628(11) 50(5) H(17) 4050(20) 6830(20) 6215(11) 50(5) H(18) 2881(18) 6441(17) 7342(9) 32(4) 272 i I (! ~) J( ) c : Figure 19. ORTEP illustration of 6g, with ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of 6g suitable for X-ray diffraction were obtained by slow evaporation of an Et20 solution of 6g. Diffraction intcnsity data were collccted with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2 . All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package data collection and crystal structure refinement for C I3H I6BNS are given in the 273 following tables. Table 62. Crystal data and structure refmement for 6g (liu37). a = 900 , ~ = 91.043(5)0. Y= 900 • Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated). Absorption coefficient F(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 27.000 Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters Goodness-of-fit on F2 Final R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole liu37 C13 H16 B N S 229.14 173(2) K 0.71073 A Monoclinic P2(1)/c a = 4.6680(10) A b = 13.476(3) A c = 19.953(4) A 1254.9(5) A3 4 1.213 Mg/m3 0.229 mm- 1 488 0.40 x 0.05 x 0.04 mm3 1.82 to 27.000. -5<=h<=5, -17<=k<=17, -25<=1<=25 13796 2723 [R(int) = 0.0845] 100.0 % Semi-empirical from equivalents 0.9909 and 0.9141 Full-matrix least-squares on F2 2723/0/209 1.021 Rl = 0.0518, wR2 = 0.1035 Rl = 0.0995, wR2 = 0.1276 0.250 and -0.263 e.A-3 Table 63. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2x 103) for 6g. U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. x y z U(eq) S(1) 903(1) 4422(1) 3511(1) 41(1) N(1) 488(4) 6028(1) 2618(1) 34(1) B(1) 1862(6) 5669(2) 3216(2) 34(1) C(1) 1177(6) 6942(2) 2360(2) 40(1) C(2) 3188(6) 7530(2) 2648(2) 44(1) C(3) 4609(6) 7237(2) 3244(2) 44(1) ------ --- 274 C(4) 4042(6) 6352(2) 3544(1) 39(1) C(5) -1649(6) 5442(2) 2233(1) 40(1) C(6) -292(8) 4836(2) 1688(2) 51(1) C(7) 3157(6) 4270(2) 4263(1) 40(1) C(8) 2806(5) 3238(2) 4534(1) 35(1) C(9) 991(6) 3043(2) 5055(1) 45(1) C(10) 662(7) 2094(2) 5305(2) 54(1) C(11) 2163(7) 1322(2) 5029(2) 55(1) C(12) 3968(8) 1505(2) 4507(2) 55(1) C(13) 4282(7) 2451(2) 4259(2) 47(1) Table 64. Bond lengths [A] and angles (OJ for 6g. S(I)-C(7) S(1)-B(l) N(1)-C(1) N(1)-B(1) N(1)-C(5) B(1)-C(4) C(1)-C(2) C(1)-H(l) C(2)-C(3) C(2)-H(2) C(3)-C(4) C(3)-H(3) C(4)-H(4) C(5)-C(6) C(5)-H(5A) C(5)-H(5B) C(6)-H(6A) C(6)-H(6B) C(6)-H(6C) C(7)-C(8) C(7)-H(7A) C(7)-H(7B) C(8)-C(9) C(8)-C(13) C(9)-C(10) C(9)-H(9) C(l 0)-C(11) C(10)-H(10) C(11)-C(l2) C(lI)-H(lI) C(12)-C(13) C(12)-H(12) C(l3)-H(l3) C(7)-S(l)-B(l) C(l)-N(l)-!3(l) C(1)-N(1)-C(5) B(1)-N(1)-C(5) N(1)-B(1)-C(4) N(1)-B(1)-S(l) C(4)-B(1)-S(l) 1.828(3) 1.838(3) 1.376(3) 1.429(3) 1.477(3) 1.512(4) 1.348(4) 0.97(2) 1.408(4) 0.96(3) 1.362(4) 0.95(3) 0.96(3) 1.507(4) 0.99(2) 0.99(2) 1.04(3) 0.96(3) 0.94(3) 1.503(3) 0.97(3) 1.01(2) 1.379(4) 1.384(4) 1.382(4) 0.95(2) 1.375(4) 1.00(3) 1.374(4) 0.91 (3) 1.375(4) 0.90(3) 0.89(3) 103.00(13) 120.7(2) 116.4(2) 122.9(2) 116.3(2) 118.0(2) 125.8(2) ---------------------- C(2)-C(1)-N(1) 122.2(3) C(2)-C(1)-H(1) 123.5(14) N(1)-C(1)-H(1) 114.1(14) C(1)-C(2)-C(3) 120.5(3) C(1)-C(2)-H(2) 117.2(16) C(3)-C(2)-H(2) 122.2(16) C(4)-C(3)-C(2) 121.6(3) C(4)-C(3)-H(3) 116.6(16) C(2)-C(3)-H(3) 121.7(16) C(3)-C(4)-B(1) 118.6(3) C(3)-C(4)-H(4) 120.2(16) B(1)-C(4)-H(4) 121.3(15) N(1)-C(5)-C(6) 112.1(3) N(1)-C(5)-H(5A) 108.9(14) C(6)-C(5)-H(5A) 109.6(14) N(1)-C(5)-H(5B) 108.5(13) C(6)-C(5)-H(5B) 111.5(14) H(5A)-C(5)-H(5B) 106(2) C(5)-C(6)-H(6A) 108.5(17) C(5)-C(6)-H(6B) 110.8(17) H(6A)-C(6)-H(6B) 105(2) C(5)-C(6)-H(6C) 109.7(17) H(6A)-C(6)-H(6C) 117(2) H(6B)-C(6)-H(6C) 106(2) C(8)-C(7)-S(1) 109.49(18) C(8)-C(7)-H(7A) 109.8(15) S(1 )-C(7)-H(7A) 109.4(16) C(8)-C(7)-H(7B) 109.7(14) S(1)-C(7)-H(7B) 109.1(13) H(7A)-C(7)-H(7B) 109(2) C(9)-C(8)-C(13) 118.1(3) C(9)-C(8)-C(7) 121.3(2) C(13)-C(8)-C(7) 120.6(3) C(8)-C(9)-C(10) 121.5(3) C(8)-C(9)-H(9) 121.0(15) C(10)-C(9)-H(9) 117.6(15) C(11)-C(10)-C(9) 119.7(3) C(11)-C(10)-H(1 0) 121.2(17) C(9)-C(10)-H(10) 119.1(17) C(10)-C(11)-C(12) 119.5(3) C(10)-C(11)-H(11) 121(2) C(12)-C(11)-H(11) 119(2) C(13)-C(12)-C(11) 120.7(3) C(13)-C(12)-H(12) 117(2) C(11 )-C(12)-H(12) 121.9(19) C(12)-C(13)-C(8) 120.7(3) C(12)-C(13)-H(13) 119.8(18) C(8)-C(13)-H(13) 119.3(18) Symmetry transfonnations used to generate equivalent atoms: 275 276 Table 65. Anisotropic displacement parameters (A2X 103)for 6g. The anisotropic displacement factor exponent takes the form: _2p2[ h2a*2U11 + .. ,+ 2 h k a* b* U12 ] Ull U22 U33 U23 Ul3 U12 S(1) 47(1) 31(1) 45(1) 7(1) -8(1) -5(1) N(1) 40(1) 22(1) 39(1) 1(1) 3(1) 3(1) B(1) 36(2) 28(1) 39(2) -1(1) 9(1) 6(1) C(1) 50(2) 28(1) 43(2) 5(1) 6(1) 7(1) C(2) 57(2) 26(1) 48(2) 4(1) 11(2) -1(1) C(3) 50(2) 31(2) 50(2) -6(1) 9(1) -6(1) C(4) 45(2) 35(2) 38(2) 0(1) 4(1) -1(1) C(5) 47(2) 32(2) 42(2) 2(1) -3(1) 2(1) C(6) 68(2) 39(2) 48(2) -6(2) 2(2) 4(2) C(7) 45(2) 35(2) 39(2) 4(1) -2(1) -3(1) C(8) 37(2) 33(1) 35(1) 1(1) -5(1) 0(1) C(9) 50(2) 40(2) 44(2) 4(1) 7(1) 5(1) C(10) 61(2) 51(2) 49(2) 14(2) 5(2) -4(2) C(11) 72(2) 35(2) 56(2) 11(2) -15(2) -7(2) C(12) 71(2) 38(2) 55(2) -3(2) -6(2) 16(2) C(13) 54(2) 45(2) 42(2) 3(1) 7(2) 5(2) Table 66. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2X 103) for 6g. x y z U(eq) H(1) 200(50) 7100(16) 1944(12) 32(7) H(2) 3610(50) 8140(20) 2426(13) 53(8) H(3) 6000(50) 7640(20) 3456(13) 49(8) H(4) 5040(50) 6168(18) 3948(14) 49(8) H(5A) -3080(50) 5898(19) 2032(12) 42(7) H(5B) -2710(50) 5015(18) 2550(12) 35(7) H(6A) -1910(70) 4480(20) 1414(16) 71(10) H(6B) 620(60) 5260(20) 1371 (15) 60(9) H(6C) 1150(60) 4430(20) 1876(14) 54(9) H(7A) 5140(60) 4382(18) 4152(13) 51(8) H(7B) 2560(50) 4769(17) 4611(12) 35(7) H(9) -100(50) 3558(19) 5252(12) 42(7) H(10) -680(70) 1980(20) 5684(15) 72(10) H(11) 1950(60) 690(20) 5180(16) 72(10) H(12) 5030(60) 1020(20) 4324(15) 62(9) H(13) 5560(60) 2568(19) 3947(14) 49(9) 277 Table 67. Torsion angles [°1 for 6g. C( 1)-N( I )-B( I )-C(4) C(5)-N( I )-B( 1)-C(4) C( 1)-N( I )-B( I )-S( I) C(5)-N( I )-B( I )-S( 1) C(7)-S( I )-B( I )-N( J) C(7)-S( I )-B( 1)-C(4) B( 1)-N( 1)-C( 1)-C(2) C(5)-N( I )-C( I )-C(2) N( I )-C( I )-C(2)-C(3) C( 1)-C(2)-C(3)-C(4) C(2)-C(3)-C(4)-B( I) N( I )-B( I )-C(4)-C(3) S( I )-B( I )-C(4)-C(3) C( 1)-N( 1)-C(5)-C(6) B( I )-N( I )-C(5)-C(6) B( I )-S( I )-C(7)-C(8) S( 1)-C(7)-C(8)-C(9) S( 1)-C(7)-C(8)-C( 13) C( 13)-C(8)-C(9)-C( I 0) C(7)-C(8)-C(9)-C( 10) C(8)-C(9)-C(10)-C(II) C(9)-C( 1O)-C( I I)-C( 12) C( 1O)-C( II )-C( 12)-C(l3) C(ll )-C( 12)-C( 13)-C(8) C(9)-C(8)-C( 13)-C( 12) C(7)-C(8)-C( 13)-C( 12) Symmetry transformations used to generate equivalent atoms: 0.8(3) 178.8(2) -178.03(18) 0.1 (3) 179.2(2) 0.6(3) 1.2(4) -177 .0(2) -2.1(4) 0.9(4) 1.0(4) -1.8(4) 176.8(2) 86.2(3) -92.0(3) -175.1(2) -98.2(3) 81.0(3) 0.7(4) 180.0(3) -0.3(5) -0.J(5) -0.1(5) 0.6(5) -0.9(4) 179.9(3) f I ell Figure 20. ORTEP illustration of 15, with ellipsoids drawn at the 35% probability level. 278 X-ray Crystal Structure Determination. Crystals of 15 suitable for X-ray diffraction were obtained by placing a vial containing 15 in a glove box freezer at -20 °C. Frozen crystals of 15 were quickly transferred to the diffractometer while attempting to keep the crystals air-free. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2. All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for CIlHlIBCIN are given in the following tables. Table 68. Crystal data and structure refinement for 15 (HuB). Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) liu13 Cl1 Hl1 B CI N 203.47 173(2) K 0.71073 A Monoclinic P2(1)/n a = 6.6633(11) A .. _ ...... ,.." .. ,. ........ , If 0= l.b4l54U j ) A C = 20.966(3) A 1060.3(3) A3 4 1.275 Mg/m3 u= 90°. ~= 97.092(2)°. y = 90°. Absorption coefficient P(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 26.99° Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters Goodness-of-fit on p2 Pinal R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole 0.316 mm-1 424 0.48 x 0.45 x 0.24 mm3 1.96 to 26.99°. -8<=h<=8, -9<=k<=9, -26<=1<=26 9247 2295 [R(int) = 0.0187] 99.1 % Semi-empirical from equivalents 1.000 and 0.642 Pull-matrix least-squares on p2 2295/0/171 1.011 Rl = 0.0340, wR2 = 0.0942 Rl = 0.0371, wR2 = 0.0971 0.336 and -0.287 e.A-3 279 Table 69. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2x 103) for 15. U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. x y z U~~ CI(1) N(1) B(1) C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(11) 8132(1) 5257(2) 7191(2) 8378(2) 7538(3) 5608(3) 4543(2) 3937(2) 4063(2) 5840(2) 5940(3) 4260(3) 2490(3) 2381(2) 1678(1) 3613(1) 3633(2) 5303(2) 6709(2) 6607(2) 5099(2) 2060(2) 1142(2) 1093(2) 167(2) -721(2) -675(2) 254(2) 246(1) 800(1) 580(1) 649(1) 911(1) 1118(1) 1062(1) 789(1) 1432(1) 1855(1) 2428(1) 2582(1) 2170(1) 1597(1) 44(1) 30(1) 31(1) 40(1) 46(1) 47(1) 39(1) 37(1) 32(1) 37(1) 45(1) 50(1) 52(1) 41(1) --------- Table 70. Bond lengths [A] and angles [0] for 15. 280 CI(1)-B(1) N(1)-C(4) N(1)-B(I) N(1)-C(5) B(1)-C(1) C(1)-C(2) C(1)-H(1) C(2)-C(3) C(2)-H(2) C(3)-C(4) C(3)-H(3) C(4)-H(4) C(5)-C(6) C(5)-H(5A) C(5)-H(5B) C(6)-C(7) C(6)-C(11) C(7)-C(8) C(7)-H(7) C(8)-C(9) C(8)-H(8) C(9)-C(10) C(9)-H(9) C(10)-C(II) C(1 0)-H(1 0) C(1I)-H(1I) C(4)-N(1)-B(1) C(4)-N(1)-C(5) B(1)-N(1 )-C(5) N(1)-B(1)-C(1) N(1)-B(1)-Cl(1) C(1)-B(1)-Cl(1) C(2)-C(1)-B(1) C(2)-C(1)-H(1) B(1)-C(1)-H(1) C(1 )-C(2)-C(3) C(1 )-C(2)-H(2) C(3)-C(2)-H(2) C(4)-C(3)-C(2) C(4)-C(3)-H(3) C(2)-C(3)-H(3) C(3)-C(4)-N(1) C(3)-C(4)-H(4) N(I)-C(4)-H(4) N(1)-C(5)-C(6) N(1 )-C(5)-H(5A) C(6)-C(5)-H(5A) N(1 )-C(5)-H(5B) C(6)-C(5)-H(5B) H(5A)-C(5)-H(5B) C(7)-C(6)-C(1I) C(7)-C(6)-C(5) 1.7962(15) 1.3723(18) 1.4220(19) 1.4762(17) 1.500(2) 1.359(2) 0.968(18) 1.409(3) 0.95(2) 1.352(2) 0.93(2) 0.952(19) 1.5144(19) 0.988(18) 0.983(18) 1.3892(19) 1.3900(19) 1.389(2) 0.971(19) 1.381(2) 0.962(18) 1.374(3) 0.99(2) 1.390(2) 0.93(2) 0.950(17) 119.57(12) 115.96(12) 124.44(12) 117.78(13) 119.43(10) 122.78(11) 118.32(14) 119.1(11) 122.6(11) 121.18(14) 122.0(12) 116.8(12) 120.62(14) 116.7(13) 122.6(13) 122.52(14) 122.0(11) 115.5(12) 113.04(11) 107.4(10) 109.4(10) 108.3(11) 111.9(10) 106.4(14) 118.58(13) 122.02(12) C(11)-C(6)-C(5) 119.34(12) C(6)-C(7)-C(8) 120.77(14) C(6)-C(7)-H(7) 119.9(10) C(8)-C(7)-H(7) 119.3(11) C(9)-C(8)-C(7) 119.97(15) C(9)-C(8)-H(8) 119.2(11) C(7)-C(8)-H(8) 120.8(11) C(1O)-C(9)-C(8) 119.88(15) C(10)-C(9)-H(9) 123.4(12) C(8)-C(9)-H(9) 116.7(12) C(9)-C(10)-C(11) 120.37(15) C(9)-C(10)-H(10) 123.2(13) C(11)-C(10)-H(10) 116.5(13) C(6)-C(11)-C(10) 120.43(15) C(6)-C(II)-H(11) 117.0(10) C(10)-C(11)-H(11) 122.6(10) Symmetry transfonnations used to generate equivalent atoms: 281 Table 71. Anisotropic displacement parameters (A2x 103)for 15. The anisotropic displacement factor exponent takes the fonn: -2n2 [ h2a*2UII + ... + 2 h k a* b* Ul2 ] U11 U22 U33 U23 Ul3 Ul2 Cl(1) 43(1) 39(1) 51(1) -8(1) 8(1) 7(1) N(1) 31(1) 28(1) 31(1) 2(1) 2(1) -2(1) B(1) 32(1) 30(1) 29(1) 1(1) 2(1) 0(1) C(1) 41(1) 42(1) 35(1) 3(1) 5(1) -12(1) C(2) 67(1) 30(1) 39(1) 2(1) -2(1) -15(1 ) C(3) 66(1) 30(1) 43(1) -4(1) 3(1) 9(1) C(4) 40(1) 40(1) 39(1) 0(1) 7(1) 9(1) C(5) 33(1) 39(1) 38(1) 1(1) 1(1) -11(1) C(6) 35(1) 26(1) 36(1) -3(1) 8(1) -2(1) C(7) 40(1) 35(1) 37(1) -1(1) 4(1) -6(1) C(8) 57(1) 40(1) 38(1) 0(1) 1(1) 0(1) C(9) 70(1) 41(1) 42(1) 7(1) 16(1) 1(1) C(10) 54(1) 44(1) 62(1) 7(1) 26(1) -7(1) C(11) 36(1) 37(1) 51(1) 1(1) 12(1) -3(1) Table 72. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2x 103) for 15. x y z U(eq) H(1) 9720(30) 5410(20) 519(8) 50(5) H(2) 8200(30) 7820(30) 950(9) 57(5) H(3) 5000(30) 7550(30) 1294(10) 61(5) H(4) 3260(30) 4990(20) 1212(9) 54(5) ur<;" ) 4360(30) 1250(20) 464(8) 47(5) ..l..l\J.cJ.) H(5B) 2550(30) 2420(20) 632(8) 45(4) H(7) 7030(30) 1700(20) 1750(8) 50(5) H(8) 7170(30) 140(20) 2723(8) 49(5) H(9) 4410(30) -1350(30) 2996(9) 57(5) H(10) 1320(30) -1240(30) 2253(10) 71(6) 282 H(ll) J 190(30) ( I. ~ II lill .~ I( (I,,(f~ / N2 \t",,-/ ~ ([ ) > 300(20) J299(8) 44(4) Figure 21. ORTEP illustration of 18, with ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of 18 suitable for X-ray diffraction were obtained by collecting the crystals that had formed when 15 was distilled to dryness after having inadvertently been exposed to air. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2. All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package 283 (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for C22H22B2N20 are given in the following tables. Table 73. Crystal data and structure refinement for 18 (Uu3). a = 90°. 13 = 106.372(2)°. y = 90°. Identification code Empirical formula Pormula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient P(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 27.00° Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters Goodness-of-fit on p2 Pinal R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole liu3 C22 H2z B2Nz 0 352.04 173(2) K 0.71073 A Monoclinic C2/c a = 19.339(2) A b = 10.9026(12) A c = 28.379(3) A 5741.1(11) A3 12 1.222 Mg/m3 0.074 mm- 1 2232 0.23 x 0.19 x 0.12 mm3 1.50 to 27.00°. -24<=h<=24, -13<=k<=13, -36<=1<=36 31623 6263 [R(int) = 0.0469] 99.9% Semi-empirical from equivalents 0.9912 and 0.9833 Pull-matrix least-squares on p2 6263/0/498 1.040 Rl = 0.0485, wR2 = 0.0972 Rl = 0.0774, wR2 = 0.1109 0.168 and -0.133 e.A-3 Table 74. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2x 103) for 18. U(eq) is dermed as one third of the trace of the orthogonalized Uij tensor. x y z U(eq) 0(1) 2026(1) 7562(1) 913(1) 40(1) 284 0(2) 0 4830(1) 2500 33(1) N(1) 1660(1) 8000(1) 53(1) 36(1) N(2) 2598(1) 7593(1) 1775(1) 33(1) N(3) 902(1) 4954(1) 2066(1) 36(1) B(1) 1655(1) 7176(2) 446(1) 34(1) B(2) 2443(1) 6945(2) 1313(1) 33(1) B(3) 341(1) 4271(2) 2190(1) 31(1) C(1) 1226(1) 6005(2) 306(1) 39(1) C(2) 868(1) 5815(2) -175(1) 45(1) C(3) 901(1) 6679(2) -540(1) 49(1) C(4) 1285(1) 7726(2) -422(1) 44(1) C(5) 2059(1) 9169(2) 138(1) 42(1) C(6) 1598(1) 10277(2) 147(1) 35(1) C(7) 1030(1) 10238(2) 355(1) 47(1) C(8) 644(1) 11293(2) 385(1) 49(1) C(9) 822(1) 12391(2) 218(1) 48(1) C(10) 1381(1) 12435(2) 4(1) 53(1) C(11) 1759(1) 11385(2) -33(1) 46(1) C(12) 2782(1) 5689(2) 1331(1) 38(1) C(13) 3214(1) 5271(2) 1767(1) 44(1) C(14) 3342(1) 5976(2) 2201(1) 48(1) C(15) 3041(1) 7096(2) 2194(1) 42(1) C(16) 2310(1) 8832(2) 1800(1) 37(1) C(17) 2715(1) 9835(1) 1620(1) 32(1) C(18) 2405(1) 10985(2) 1534(1) 47(1) C(19) 2757(1) 11939(2) 1377(1) 58(1) C(20) 3423(1) 11756(2) 1303(1) 48(1) C(21) 3737(1) 10616(2) 1389(1) 42(1) C(22) 3384(1) 9659(2) 1546(1) 37(1) C(23) 172(1) 3023(2) 1951(1) 36(1) C(24) 538(1) 2641(2) 1633(1) 44(1) C(25) 1081(1) 3368(2) 1532(1) 51(1) C(26) 1253(1) 4471(2) 1748(1) 47(1) C(27) 1103(1) . 6198(2) 2251(1) 41(1) C(28) 701(1) 7201(2) 1917(1) 36(1) C(29) 498(1) 7100(2) 1407(1) 42(1) C(30) 145(1) 8054(2) 1115(1) 51(1) C(31) -15(1 ) 9117(2) 1323(1) 56(1) C(32) 186(1) 9230(2) 1828(1) 56(1) C(33) 544(1) 8280(2) 2121(1) 46(1) Table 75. Bond lengths [A] and angles [0] for 18. 0(1)-B(2) 1.369(2) O(1)-B(1) 1.382(2) 0(2)-B(3)#1 1.3797(18) 0(2)-B(3) 1.3797(18) N(l)-C(4) 1.371(2) N(1)-B(1) 1.434(2) N(1)-C(5) 1.474(2) N(2)-C(15) 1.367(2) N(2)-B(2) 1.445(2) N(2)-C(16) 1.471(2) N(3)-C(26) N(3)-B(3) N(3)-C(27) B(I)-C(1) B(2)-C(12) B(3)-C(23) C(1)-C(2) C(I)-H(1) C(2)-C(3) C(2)-H(2) C(3)-C(4) C(3)-H(3) C(4)-H(4) C(5)-C(6) C(5)-H(5A) C(5)-H(5B) C(6)-C(11) C(6)-C(7) C(7)-C(8) C(7)-H(7) C(8)-C(9) C(8)-H(8) C(9)-C(10) C(9)-H(9) C(1O)-C(11 ) C(1O)-H(10) C(1I)-H(1I) C(12)-C(13) C(12)-H(12) C(13)-C(14) C(13)-H(13) C(14)-C(15) C(l4)-H(14) C(15)-H(15) C(16)-C(17) C(16)-H(16A) C(16)-H(16B) C(17)-C(18) C(17)-C(22) C(18)-C(19) C(18)-H(18) C(19)-C(20) C(19)-H(19) C(20)-C(21 ) C(20)-H(20) C(21 )-C(22) C(2 1)-H(21 ) C(22)-H(22) C(23)-C(24) C(23)-H(23) C(24)-C(25) C(24)-H(24) C(25)-C(26) 1.378(2) 1.440(2) 1.467(2) 1.514(3) 1.514(2) 1.515(2) 1.362(2) 0.944(17) 1.415(3) 0.971(18) 1.350(3) 0.936(19) 0.959(18) 1.506(2) 0.999(18) 1.03(2) 1.381(2) 1.386(2) 1.387(2) 0.974(19) 1.368(3) 0.99(2) 1.382(3) 0.995(18) 1.379(3) 0.98(2) 0.966(18) 1.363(2) 0.964(16) 1.413(3) 0.996(18) 1.351(3) 0.98(2) 0.993(17) 1.516(2) 0.980(16) 1.010(18) 1.381(2) 1.383(2) 1.384(3) 0.994(18) 1.378(3) 0.97(2) 1.374(3) 0.948(19) 1.387(2) 0.987(18) () 011')(1 ~\ "1.'/ VoW,,LV J 1.359(2) 0.959(16) 1.408(3) 1.003(18) 1.349(3) 285 C(25)-H(25) C(26)-H(26) C(27)-C(28) C(27)-H(27A) C(27)-H(27B) C(28)-C(33 ) C(28)-C(29) C(29)-C(30) C(29)-H(29) C(30)-C(31 ) C(30)-H(30) C(31)-C(32) C(31 )-H(31) C(32)-C(33) C(32)-H(32) C(33)-H(33) B(2)-0(1 )-B(1 ) B(3)#1-0(2)-B(3) C(4)-N(1)-B(1) C(4)-N(1)-C(5) B(1)-N(1)-C(5) C(15)-N(2)-B(2) C(15)-N(2)-C(16) B(2)-N(2)-C(16) C(26)-N(3)-B(3) C(26)-N(3)-C(27) B(3)-N(3)-C(27) O(1)-B(1)-N(1) 0(1)-B(1)-C(1 ) N(1)-B(1)-C(1) 0(1)-B(2)-N(2) 0(1 )-B(2)-C(12) N(2)-B(2)-C(12) 0(2)-B(3)-N(3) 0(2)-B(3)-C(23) N(3)-B(3)-C(23) C(2)-C(1)-B(1) C(2)-C(1)-H(1) B(1)-C(1)-H(1) C(1 )-C(2)-C(3) C(1)-C(2)-H(2) C(3)-C(2)-H(2) C(4)-C(3)-C(2) C(4)-C(3)-H(3) C(2)-C(3)-H(3) C(3)-C(4)-N(1) C(3)-C(4)-H(4) N(1)-C(4)-H(4) N(1 )-C(5)-C(6) N(1 )-C(5)-H(5A) C(6)-C(5)-H(5A) N(1)-C(5)-H(5B) C(6)-C(5)-H(5B) 0.974(18) 0.988(18) 1.512(2) 1.006(18) 0.997(17) 1.382(2) 1.392(2) 1.384(3) 0.956(18) 1.374(3) 0.977(19) 1.379(3) 0.98(2) 1.385(3) 1.00(2) 0.965(18) 132.08(14) 127.59(18) 120.72(15) 117.14(15) 122.14(14) 121.00(14) 118.37(14) 120.58(14) 120.53(15) 117.22(15) 122.20(14) 116.11(15) 127.32(15) 116.53(15) 115.81(15) 128.35(16) 115.80(15) 117.13(15) 126.99(15) 115.84(14) 118.52(17) 119.2(11) 122.2(11) 121.21(19) 119.9(11) 118.9(10) 120.99(18) 120.3(12) 118.7(12) 122.02(17) 123.3(11) 114.7(11) 114.32(14) 109.4(10) 108.8(10) 106.7(10) 109.0(10) 286 H(5A)-C(5)-H(5B) C(11 )-C(6)-C(7) C(11)-C(6)-C(5) C(7)-C(6)-C(5) C(6)-C(7)-C(8) C(6)-C(7)-H(7) C(8)-C(7)-H(7) C(9)-C(8)-C(7) C(9)-C(8)-H(8) C(7)-C(8)-H(8) C(8)-C(9)-C(10) C(8)-C(9)-H(9) C(10)-C(9)-H(9) C(11 )-C(10)-C(9) C(11)-C(10)-H(10) C(9)-C(10)-H(10) C(1 O)-C(11 )-C(6) C(10)-C(11)-H(11) C(6)-C(II)-H(11) C(13)-C(12)-B(2) C(13)-C(12)-H(12) B(2)-C(12)-H(12) C(12)-C( 13)-C(14) C(12)-C(13)-H(13) C(l4)-C(13)-H(13) C(15)-C(14)-C(13) C(15)-C(14)-H(14) C(13)-C(14)-H(14) C(l4)-C(15)-N(2) C(14)-C(15)-H(15) N(2)-C(15)-H(15) N(2)-C(16)-C(17) N(2)-C(16)-H(16A) C(17)-C(16)-H(16A) N(2)-C(16)-H(16B) C(l7)-C(16)-H(16B) H(l6A)-C(16)-H(16B) C(18)-C(17)-C(22) C(18)-C(17)-C(16) C(22)-C(17)-C(16) C(l7)-C(18)-C(19) C(l7)-C(18)-H(18) C(l9)-C( 18)-H(18) C(20)-C(19)-C(18) C(20)-C(19)-H(19) C(l8)-C(19)-H(19) C(21)-C(20)-C(19) C(21)-C(20)-H(20) C(19)-C(20)-H(20) C(20)-C(21 )-C(22) C(20)-C(21 )-H(21) C(22)-C(21 )-H,(21) C(17)-C(22)-C(21) 108.4(14) 118.22(16) 119.93(15) 121.77(15) 120.44(18) 118.1(11) 121.4(11) 120.72(18) 121.4(11) 117.9(11) 119.23(17) 120.2(10) 120.5(10) 120.14(19) 122.3(12) 117.6(12) 121.21(17) 119.7(11) 119.1(11) 118.77(16) 118.0(10) 123.3(10) 121.53(17) 120.3(10) 118.1(10) 120.65(17) 118.6(11) 120.7(11) 122.23(17) 122.1(10) 115.6(10) 114.01(13) 108.8(9) 108.2(9) 109.1(10) 107.8(10) 108.8(13) 118.55(15) 118.34(14) 123.10(15) 120.72(17) 117.9(10) 121.4(10) 120.43(18) 119.4(13) 120.2(13) 119.25(18) 119.7(11) 121.0(11) 120.36(17) 119.8(10) 119.9(10) 120.69(16) 287 C(17)-C(22)-H(22) 118.7(9) C(21 )-C(22)-H(22) 120.6(9) C(24)-C(23)-B(3) 119.17(17) C(24)-C(23)-H(23) 117.4(9) B(3)-C(23)-H(23) 123.4(9) C(23)-C(24)-C(25) 121.30(18) C(23)-C(24)-H(24) 120.7(10) C(25)-C(24)-H(24) 118.0(10) C(26)-C(25)-C(24) 120.86(17) C(26)-C(25)-H(25) 118.8(11) C(24)-C(25)-H(25) 120.3(11) C(25)-C(26)-N(3) 122.27(18) C(25)-C(26)-H(26) 123.8(10) N(3)-C(26)-H(26) 113.9(10) N(3)-C(27)-C(28) 114.00(14) N(3)-C(27)-H(27A) 109.1(10) C(28)-C(27)-H(27A) 110.0(10) N(3)-C(27)-H(27B) 107.9(9) C(28)-C(27)-H(27B) 109.6(9) H(27A)-C(27)-H(27B) 105.9(14) C(33)-C(28)-C(29) 118.13(17) C(33)-C(28)-C(27) 119.22(16) C(29)-C(28)-C(27) 122.62(16) C(30)-C(29)-C(28) 120.63(19) C(30)-C(29)-H(29) 119.5(11) C(28)-C(29)-H(29) 119.7(11) C(31 )-C(30)-C(29) 120.64(19) C(31)-C(30)-H(30) 121.3(11) C(29)-C(30)-H(30) 118.1(11) C(30)-C(31 )-C(32) 119.2(2) C(30)-C(31)-H(31) 119.0(12) C(32)-C(31)-H(31) 121.8(12) C(31)-C(32)-C(33) 120.2(2) C(31)-C(32)-H(32) 120.4(12) C(33)-C(32)-H(32) 119.3(12) C(28)-C(33)-C(32) 121.10(19) C(28)-C(33)-H(33) 117.8(11) C(32)-C(33)-H(33) 121.1(11) Symmetry transfonnations used to generate equivalent atoms: #1 -x,y,-z+1/2 288 Table 76. Anisotropic displacement parameters (A2x 103)for 18. The anisotropic displacement factor exponent takes the fonn: -2p2[ h2a*2U11 + .. , + 2 h k a* b* Ul2 ] 0(1) 0(2) N(1) N(2) N(3) B(1) B(2) 49(1) 37(1) 37(1) 34(1) 34(1) 34(1) 33(1) 34(1) 32(1) 37(1) 30(1) 40(1) 36(1) 34(1) 35(1) 34(1) 37(1) 36(1) 35(1) 33(1) 34(1) 2(1) o 4(1) 1(1) 4(1) 1(1) 2(1) 8(1) 16(1) 17(1) 12(1) 14(1) 13(1) 13(1) 2(1) o 10(1) -3(1) 2(1) 9(1) -5(1) 289 B(3) 30(1) 35(1) 28(1) 5(1) 9(1) 6(1) C(1) 41(1) 39(1) 40(1) 2(1) 14(1) 7(1) C(2) 41(1) 41(1) 51(1) -10(1) 9(1) 9(1) C(3) 52(1) 59(1) 32(1) -7(1) 4(1) 23(1) C(4) 51(1) 51(1) 35(1) 7(1) 19(1) 21(1) C(5) 39(1) 41(1) 53(1) 11(1) 23(1) 7(1) C(6) 35(1) 39(1) 33(1) 3(1) 13(1) 4(1) C(7) 51(1) 44(1) 55(1) 7(1) 31(1) 6(1) C(8) 49(1) 54(1) 54(1) -5(1) 28(1) 8(1) C(9) 47(1) 43(1) 52(1) -10(1) 12(1) 10(1) C(10) 51(1) 37(1) 71(1) 6(1) 19(1) 5(1) C(11) 41(1) 42(1) 58(1) 8(1) 21(1) 6(1) C(12) 44(1) 34(1) 39(1) -1(1) 16(1) -3(1) C(13) 42(1) 37(1) 52(1) 6(1) 11(1) 4(1) C(14) 48(1) 46(1) 42(1) 9(1) 0(1) -1(1) C(15) 44(1) 45(1) 33(1) 0(1) 7(1) -7(1) C(16) 39(1) 36(1) 42(1) -4(1) 18(1) -2(1) C(17) 31(1) 34(1) 30(1) -5(1) 9(1) -3(1) C(18) 35(1) 39(1) 70(1) 3(1) 19(1) 2(1) C(19) 49(1) 37(1) 89(2) 12(1) 22(1) 5(1) C(20) 50(1) 41(1) 56(1) 7(1) 20(1) -9(1) C(21) 39(1) 43(1) 48(1) -7(1) 19(1) -7(1) C(22) 37(1) 34(1) 44(1) -3(1) 15(1) 0(1) C(23) 39(1) 34(1) 35(1) 2(1) 9(1) 4(1) C(24) 57(1) 39(1) 33(1) 0(1) 9(1) 17(1) C(25) 61(1) 57(1) 43(1) 7(1) 28(1) 23(1) C(26) 42(1) 60(1) 47(1) 14(1) 26(1) 10(1) C(27) 40(1) 47(1) 37(1) 4(1) 11(1) -12(1) C(28) 33(1) 40(1) 39(1) 3(1) 15(1) -11(1) C(29) 47(1) 43(1) 38(1) 1(1) 16(1) -10(1) C(30) 51(1) 59(1) 40(1) 12(1) 8(1) -13(1) C(31) 43(1) 50(1) 70(2) 19(1) 10(1) -5(1) C(32) 50(1) 45(1) 74(2) -3(1) 21(1) -2(1) C(33) 46(1) 50(1) 45(1) -5(1) 15(1) -8(1) Table 77. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2x 103) for 18. x y z U(eq) H(1) 1208(9) 5398(16) 539(6) 50(5) H(2) 591(9) 5070(17) -273(6) 52(5) H(3) 649(10) 6516(17) -867(7) 63(6) H(4) 1328(10) 8323(17) -660(7) 56(6) H(5A) 2310(9) 9287(16) -122(6) 53(5) H(5B) 2441(11) 9092(17) 471(7) 61(6) H(7) 909(10) 9452(18) 474(7) 60(6) H(8) 233(11) 11221(17) 525(7) 67(6) H(9) 537(9) 13140(16) 237(6) 51(5) H(10) 1487(10) 13225(19) -122(7) 69(6) H(11) 2147(10) 11421(16) -185(6) 55(5) H(12) 2704(9) 5160(15) 1048(6) 41(5) H(13) 3451(10) 4453(17) 1788(6) 56(5) H(14) 3656(10) 5665(17) 2513(7) 65(6) H(15) H(16A) H(16B) H(18) H(19) H(20) H(21) H(22) H(23) H(24) H(25) H(26) H(27A) H(27B) H(29) H(30) H(31) H(32) H(33) 3127(9) 2329(8) 1791(10) 1927(10) 2531(11) 3668(10) 4214(10) 3606(9) -194(8) 439(9) 1332(9) 1633(10) 1638(10) 1013(9) 578(9) 4(10) -275(10) 59(11) 678(10) 7612(15) 9011(14) 8859(15) 11104(16) 12740(20) 12404(17) 10477(16) 8843(15) 2490(14) 1815(17) 3088(16) 5010(16) 6308(15) 6269(14) 6348(17) 7941(17) 9773(18) 9980(20) 8339(16) 2493(6) 2142(6) 1594(6) 1593(6) 1311(7) 1195(6) 1336(6) 1607(6) 2002(6) 1472(6) 1299(7) 1692(6) 2311(6) 2579(6) 1258(6) 759(7) 1107(7) 1986(8) 2474(7) 47(5) 37(4) 49(5) 57(5) 79(7) 58(6) 53(5) 41(5) 38(4) 54(5) 56(5) 53(5) 51(5) 43(5) 51(5) 63(6) 66(6) 78(7) 57(6) 290 Table 78. Torsion angles [0] for 18. B(2)-0(1)-B(1)-N(1) B(2)-0(1 )-B(1 )-C(1) C(4)-N(1)-B(1 )-0(1) C(5)-N(1)-B(1 )-0(1) C(4)-N(1)-B(1)-C(1 ) C(5)-N(1 )-B(1)-C(l) B(1)-0(1)-B(2)-N(2) B(l )-0(1 )-B(2)-C(12) C(15)-N(2)-B(2)-0(1) C(16)-N(2)-B(2)-0(1) C(15)-N(2)-B(2)-C(12) C(16)-N(2)-B(2)-C(12) B(3)#1-0(2)-B(3)-N(3) B(3)#1-0(2)-B(3)-C(23) C(26)-N(3)-B(3)-0(2) C(27)-N(3)-B(3)-0(2) C(26)-N(3)-B(3)-C(23) C(27)-N(3)-B(3)-C(23) 0(1)-B(1)-C(1)-C(2) N(1 )-B(1 )-C(1)-C(2) B(1)-C(1 )-C(2)-C(3) C(1 )-C(2)-C(3)-C(4) C(2)-C(3)-C(4)-N(1) B(1)-N(1)-C(4)-C(3) C(5)-N(1)-C(4)-C(3) C(4)-N(l)-C(5)-C(6) B(1)-N(1 )-C(5)-C(6) N(1)-C(5)-C(6)-C(11) N(1)-C(5)-C(6)-C(7) C(11)-C(6)-C(7)-C(8) C(5)-C(6)-C(7)-C(8) -142.21(16) 40.0(3) -177.43(14) 2.3(2) 0.6(2) -179.74(14) -165.22(15) 17.1 (3) -176.41(14) 0.8(2) 1.6(2) 178.71(14) -154.12(15) 28.07(13) -178.17(13) -0.9(2) -0.1 (2) 177.16(14) 176.92(16) -0.8(2) 0.8(2) -0.5(3) 0.2(3) -0.3(2) 180.00(15) 79.51(19) -100.18(18) -145.76(16) 37.5(2) -0.9(3) 175.96(18) C(6)-C(7)-C(8)-C(9) C(7)-C(8)-C(9)-C( 10) C(8)-C(9)-C(10)-C(11) C(9)-C(10)·C(11)-C(6) C(7)-C(6)-C(11)-C(1 0) C(5)-C(6)-C(11)-C(10) O( 1)-B(2)-C(12)-C(13) N(2)-B(2)-C( 12)-C(13) B(2)-C(12)-C(13)-C(14) C(12)-C(13)-C( 14)-C( 15) C( 13)-C(14)-C(15)-N(2) B(2)-N(2)-C( 15)-C(14) C( 16)-N(2)-C( 15)-C(14) C(15)-N(2)-C(16)-C(17) B(2)-N(2)-C(16)-C(17) N(2)-C(16)-C( 17)-C(18) N(2)-C( 16)-C(17)-C(22) C(22)-C(17)-C(18)-C(19) C(16)-C(17)-C(18)-C( 19) C(17)-C(18)-C( 19)-C(20) C( 18)-C(19)-C(20)-C(21) C(19)-C(20)-C(21 )-C(22) C(18)-C(17)-C(22)-C(21) C( 16)-C(17)-C(22)-C(21) C(20)-C(21)-C(22)-C(17) O(2)-B(3)-C(23)-C(24) N(3)-B(3)-C(23)-C(24) B(3)-C(23)-C(24)-C(25) C(23)-C(24)-C(25)-C(26) C(24)-C(25)-C(26)-N(3) B(3)-N(3)-C(26)-C(25) C(27)-N(3)-C(26)-C(25) C(26)-N(3)-C(27)-C(28) B(3)-N(3)-C(27)-C(28) N(3)-C(27)-C(28)-C(33) N(3)-C(27)-C(28)-C(29) C(33)-C(28)-C(29)-C(30) C(27)-C(28)-C(29)-C(30) C(28)-C(29)-C(30)-C(31) C(29)-C(30)-C(31 )-C(32) C(30)-C(31)-C(32)-C(33) C(29)-C(28)-C(33)-C(32) C(27)-C(28)-C(33)-C(32) C(31 )-C(32)-C(33)-C(28) Symmetry transfonnations used to generate equivalent atoms: #1 -x,y,-z+1I2 -0.9(3) 1.8(3) -0.9(3) -0.9(3) 1.8(3) -175.13(18) 176.32(16) -1.3(2) 0.8(3) -0.4(3) 0.6(3) -1.2(2) -178.45(16) 99.37(17) -77.86(19) 167.06(15) -14.2(2) 0.1(3) 178.89(18) 0.1(3) -0.3(3) 0.4(3) 0.0(2) -178.72(16) -0.3(3) 176.43(15) -1.4(2) 1.5(2) -0.1(3) -1.6(3) 1.6(3) -175.81(17) 85.82(19) -91.55(18) 147.24(15) -34.6(2) -0.4(2) -178.51(16) -0.3(3) 0.5(3) 0.0(3) 0.8(3) 179.03(16) -0.6(3) 291 292 (~ I I(n -)~ ( I Figure 22. ORTEP illustration of 19, with ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of 19 suitable for X-ray diffraction were obtained by slow evaporation of an Et20 solution of 19. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2. All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.She1drick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for C 17H t6BN are given in the following tablcs. 293 Table 79. Crystal data and structure refmement for 19 (liu5). a = 103.079(2)°. P= 102.604(2)°. y = 113.009(2)°. Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions liu5 C17 H16 B N 245.12 173(2) K 0.71073 A Triclinic P-l a = 8.0839(8) A b = 9.9545(10) A c = 10.0860(10) A Volume 683.79(12) A3 Z 2 Density (calculated) 1.191 Mg/m3 Absorption coefficient 0.068 mm-1 F(OOO) 260 Crystal size 0.29 x 0.16 x 0.12 mm3 Theta range for data collection 2.21 to 27.50°. Index ranges -1O<=h<=10, -12<=k<=12, -12<=1<=12 Reflections collected 7826 Independent reflections 3079 [R(int) = 0.0193] Completeness to theta = 27.50° 97.9 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.9919 and 0.9806 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 3079/0/236 Goodness-of-fit on F2 1.014 ----- ------~---- -- ---~-- -~-- ------------ Final R indices [I>2sigma(I)] Rl = 0.0476, wR2 = 0.1206 R indices (all data) Rl = 0.0602, wR2 = 0.1302 Largest diff. peak and hole 0.266 and -0.181 e.A-3 Table 80. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2x 103) for 19. V(eq) is defmed as one third of the trace of the orthogonalized Vij tensor. x y z V(eq) B(1) 1564(2) 2558(2) 4775(2) 28(1) N(1) 1968(2) 1904(1) 5858(1) 29(1) C(l) 1h'2r?\ 3208(2) 4880(2) 33(1) - - - ....- ~ C(2) -586(2) 3173(2) 5975(2) 37(1) C(3) -96(2) 2500(2) 6991(2) 38(1) C(4) 1116(2) 1884(2) 6901(2) 34(1) C(5) 3193(2) 1117(2) 5902(2) 33(1) C(6) 4812(2) 1808(2) 7335(2) 28(1) 294 C(7) 5236(2) 828(2) 7973(2) 33(1) C(8) 6707(2) 1433(2) 9288(2) 37(1) C(9) 7766(2) 3029(2) 9988(2) 36(1) C(10) 7351(2) 4014(2) 9359(2) 35(1) C(11) 5889(2) 3408(2) 8039(2) 32(1) C(12) 2433(2) 2557(2) 3520(2) 27(1) C(13) 1168(2) 1982(2) 2093(2) 31(1) C(14) 1809(2) 2011(2) 925(2) 35(1) C(15) 3742(2) 2632(2) 1150(2) 36(1) C(16) 5035(2) 3219(2) 2545(2) 36(1) C(17) 4384(2) 3176(2) 3705(2) 32(1) Table 81. Bond lengths [A] and angles [0] for 19. B(1)-N(1) 1.434(2) B(1 )-C(1) 1.520(2) B(1)-C(12) 1.576(2) N(1)-C(4) 1.377(2) N(1 )-C(5) 1.483(2) C(1)-C(2) 1.371(2) C(1)-H(1) 0.994(18) C(2)-C(3) 1.412(2) C(2)-H(2) 1.02(2) C(3)-C(4) 1.353(2) C(3)-H(3) 0.96(2) C(4)-H(4) 0.961(19) C(5)-C(6) 1.515(2) C(5)-H(5A) 1.00(2) C(5)-H(5B) 1.001(19) C(6)-C(7) 1.390(2) C(6)-C(11) 1.391(2) C(7)-C(8) 1.388(2) C(7)-H(7) 0.971(19) C(8)-C(9) 1.386(2) C(8)-H(8) 0.948(19) C(9)-C(10) 1.387(2) C(9)-H(9) 0.970(18) C(10)-C(11) 1.387(2) C(1O)-H(10) 0.98(2) C(11)-H(11) 0.965(18) C(12)-C(17) 1.400(2) C(12)-C(13) 1.404(2) C(13)-C(14) 1.389(2) C(13)-H(13) 0.972(17) C(14)-C(15) 1.380(2) C(14)-H(14) 0.974(19) C(15)-C(16) 1.386(2) C(15)~H(15) 1.00(2) C(16)-C(17) 1.386(2) C(16)-H(16) 0.97(2) C(17)-H(17) 0.960(18) N(l)-B(1)-C(l) 115.24(14) N(1)-B(1)-C(12) 123.18(14) C(l)-B(1)-C(12) C(4)-N(1)-B(1) C(4)-N(1)-C(5) B(l)-N(1)-C(5) C(2)-C(l)-B(1) C(2)-C(l)-H(1) B(l)-C(l)-H(l) C(1)-C(2)-C(3) C(1)-C(2)-H(2) C(3)-C(2)-H(2) C(4)-C(3)-C(2) C(4)-C(3)-H(3) C(2)-C(3)-H(3) C(3)-C(4)-N(1) C(3)-C(4)-H(4) N(1)-C(4)-H(4) N(1)-C(5)-C(6) N(1)-C(5)-H(5A) C(6)-C(5)-H(5A) N(1)-C(5)-H(5B) C(6)-C(5)-H(5B) H(5A)-C(5)-H(5B) C(7)-C(6)-C(11) C(7)-C(6)-C(5) C(11)-C(6)-C(5) C(8)-C(7)-C(6) C(8)-C(7)-H(7) C(6)-C(7)-H(7) C(9)-C(8)-C(7) C(9)-C(8)-H(8) C(7)-C(8)-H(8) C(8)-C(9)-C(10) C(8)-C(9)-H(9) C(10)-C(9)-H(9) C(9)-C(10)-C(11) C(9)-C(10)-H(10) C(1l)-C(1 O)-H(1 0) C(10)-C(11)-C(6) C(10)-C(11)-H(11) C(6)-C(11)-H(11) C(17)-C(12)-C(13) C(17)-C(12)-B(1) C(13)-C(12)-B(1) C(14)-C(13)-C(12) C(14)-C( 13)-H(13) C(12)-C(13)-H(13) C(15)-C(14)-C(13) C(15)-C(14)-H(14) C(13)-C(14)-H(14) C(14)-C( 15)-C(16) C(14)-C(15)-H(15) C(16)-C(15)-H(15) C(15)-C(16)-C(17) 121.54(13) 120.87(13) 114.82(13) 124.18(13) 120.01(15) 119.5(11) 120.4(11) 120.40(15) 119.6(11) 120.0(11) 120.64(15) 119.2(12) 120.2(12) 122.80(15) 121.2(11) 116.0(11) 113.06(12) 109.6(11) 108.5(10) 108.4(11) 110.4(10) 106.7(15) 118.79(14) 119.66(14) 121.54(13) 120.73(15) 119.1(10) 120.2(10) 120.16(15) 119.0(12) 120.9(12) 119.45(15) 121.7(11) 118.8(11) 120.32(15) 120.4(12) 119.3(12) 120.55(15) 117.9(11) 121.5(11) 116.43(14) 125.62(13) 117.82(13) 121.96(14) 118.5(10) 119.5(10) 119.98(15) 120.4(11) 119.6(12) 119.63(15) 120.3(11) 119.9(11) 120.08(15) 295 --------------- -- --- 296 C(15)-C(16)-H(16) 119.0(11) C(17)-C(16)-H(16) 120.9(11) C(16)-C(17)-C(12) 121.91(15) C(16)-C(17)-H(17) 119.8(11) C(12)-C(17)-H(17) 118.2(11) Symmetry transfonnations used to generate equivalent atoms: Table 82. Anisotropic displacement parameters (A2x 103)for 19. The anisotropic displacement factor exponent takes the fonn: _2p2[ h2a*2UII + ... + 2 h k a* b* Ul2 ] Ull U22 U33 U23 UB Ul2 B(1) 28(1) 27(1) 25(1) 6(1) 6(1) 11(1) N(1) 30(1) 31(1) 22(1) 7(1) 6(1) 14(1) C(1) 33(1) 34(1) 33(1) 12(1) 11(1) 17(1) C(2) 33(1) 38(1) 37(1) 7(1) 12(1) 17(1) C(3) 35(1) 48(1) 27(1) 8(1) 14(1) 15(1) C(4) 35(1) 39(1) 23(1) 11(1) 7(1) 13(1) C(5) 39(1) 31(1) 26(1) 8(1) 6(1) 19(1) C(6) 30(1) 31(1) 27(1) 11(1) 11(1) 16(1) C(7) 33(1) 32(1) 35(1) 15(1) 11(1) 16(1) C(8) 37(1) 46(1) 40(1) 24(1) 14(1) 25(1) C(9) 27(1) 50(1) 31(1) 15(1) 9(1) 18(1) C(10) 29(1) 34(1) 35(1) 9(1) 10(1) 11(1) C(11) 34(1) 31(1) 31(1) 13(1) 10(1) 15(1) C(12) 31(1) 27(1) 27(1) 11(1) 10(1) 16(1) C(13) 29(1) 37(1) 29(1) 14(1) 10(1) 16(1) C(14) 38(1) 41(1) 27(1) 13(1) 10(1) 19(1) C(15) 43(1) 39(1) 36(1) 16(1) 21(1) 22(1) C(16) 31(1) 38(1) 44(1) 14(1) 17(1) 17(1) C(17) 31(1) 33(1) 30(1) 7(1) 6(1) 16(1) Table 83. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2x 103) for 19. x y z U(eq) H(1) -180(30) 3700(20) 4180(20) 39(5) H(2) -1500(30) 3630(20) 6050(20) 47(5) H(3) -620(30) 2480(20) 7760(20) 45(5) H(4) 1430(30) 1400(20) 7570(20) 41(5) H(5A) 2400(30) -10(20) 5720(20) 42(5) H(5B) 3710(30) 1170(20) 5090(20) 42(5) H(7) 4500(30) -290(20) 7501(19) 37(5) H(8) 7000(30) 770(20) 9720(20) 42(5) H(9) 8790(30) 3480(20) 10910(20) 37(5) H(10) 8110(30) 5150(30) 9830(20) 53(6) H(lI) 5640(20) 4130(20) 7637(19) 37(5) H(l3) -200(20) 1565(19) 1911(17) 29(4) H(14) 890(30) 1620(20) -50(20) 47(5) H(15) 4220(30) 2720(20) 320(20) 51(5) H(16) 6390(30) 3650(20) 2690(20) 46(5) H(17) 5280(30) 3610(20) 4670(20) 37(5) Table 84. Torsion angles [0] for 19. C(1 )-B(1)-N(1)-C(4) C(12)-B(1)-N(1)-C(4) C(I )-B(1 )-N(1 )-C(5) C(12)-B(1)-N(1)-C(5) N(1 )-B(1 )-C(1)-C(2) C(12)-B( I)-C( I)-C(2) B(1 )-C(1 )-C(2)-C(3) C(1)-C(2)-C(3)-C(4) C(2)-C(3)-C(4)-N(1) B(1)-N(1 )-C(4)-C(3) C(5)-N(1)-C(4)-C(3) C(4)-N (1 )-C(5)-C(6) B(1 )-N(I )-C(5)-C(6) N(1)-C(5)-C(6)-C(7) N(1)-C(5)-C(6)-C(1I) C(11 )-C(6)-C(7)-C(8) C(5)-C(6)-C(7)-C(8) C(6)-C(7)-C(8)-C(9) C(7)-C(8)-C(9)-C( I0) C(8)-C(9)-C(1 O)-C( II) C(9)-C( I0)-C(11)-C(6) C(7)-C(6)-C(11 )-C(10) C(5)-C(6)-C(11)-C(1 0) N(1 )-B(1 )-C(12)-C(17) C(1)-B(1)-C(12)-C(17) N( l)-B(1 )-C( 12)-C(13) C(1)-B(1)-C(12)-C(13) C(17)-C(12)-C(13)-C(14) B(1 )-C( 12)-C(13)-C(14) C(12)-C( 13)-C( 14)-C(15) C(13)-C(14)-C(15)-C( 16) C(14)-C( 15)-C(16)-C(17) C(15)-C(16)-C(17)-C(12) C(13)-C(12)-C(17)-C(16) B(1)-C(12)-C(17)-C(16) Symmetry transformations used to generate equivalent atoms: 0.2(2) -177.59(13) 175.90(13) -1.9(2) 1.4(2) 179.17(14) -1.5(2) 0.0(3) 1.6(3) -1.7(2) -177.78(15) -58.78(18) 125.26(15) 136.53(15) -43.2(2) -0.1(2) -179.77(15) 0.5(2) -0.4(2) 0.0(2) 0.4(2) -0.4(2) 179.29(15) -55.8(2) 126.60(17) 128.60(16) -49.0(2) 0.5(2) 176.50(14) -0.6(2) 0.3(2) 0.2(2) -0.4(2) 0.0(2) -175.65(14) 297 298 l! / J ~) /~) Figure 23. ORTEP illustration of20, with ellipsoids drawn at the 35% probability level. ( I X-ray Crystal Structure Determination. Crystals of20 suitable for X-ray diffraction were obtained by slow evaporation of an EtzO solution of 20. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on FZ• All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of 299 data collection and crystal structure refmement for Cn H16BN are given in the following tables. Table 85. Crystal data and structure refinement for 20 (liu39a). a = 90°. P= 90°. y = 90°. Identification code Empirical formula Pormula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient P(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 26.00° Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters Goodness-of-fit on p2 Final R indices [I>2sigma(I)] R indices (all data) Absolute structure parameter Largest diff. peak and hole liu39a Cn H16 B N 269.14 173(2) K 0.71073 A Orthorhombic Pna2(1) a = 11.1782(11) A b= 16.9314(17) A c = 8.1703(8) A 1546.3(3) A3 4 1.156 Mg/m3 0.066 mm- l 568 0.28 x 0.18 x 0.04 mm3 2.18 to 26.00°. -l1<=h<=13, -20<=k<=20, -10<=1<=7 8760 2798 [R(int) = 0.0498] 99.9% Semi-empirical from equivalents 0.9974 and 0.9818 Pull-matrix least-squares on p2 2798/1/254 1.029 Rl = 0.0547, wR2 = 0.1137 Rl = 0.0887, wR2 = 0.1353 0(5) 0.211 and -0.127 e.A-3 --------~~- _._-- 300 Table 86. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2x 103) for 20. U(eq) is defmed as one third of the trace of the orthogonalized Uii tensor. x y z U(eq) N(1) 144(2) 1505(1) 8225(3) 36(1) B(1) 1125(3) 1917(2) 7485(6) 33(1) C(1) 126(3) 676(2) 8296(5) 46(1) C(2) 1036(3) 248(2) 7585(6) 59(1) C(3) 2028(3) 603(2) 6892(5) 55(1) C(4) 2142(3) 1420(2) 6837(4) 45(1) C(5) 1088(2) 2822(2) 7441(4) 37(1) C(6) 1108(2) 3536(2) 7407(5) 35(1) C(7) 1189(2) 4391(1) 7411(4) 34(1) C(8) 425(3) 4833(2) 8412(4) 51(1) C(9) 537(4) 5649(2) 8439(5) 60(1) C(1O) 1370(3) 6024(2) 7477(5) 54(1) C(ll) 2122(3) 5585(2) 6508(5) 51(1) C(12) 2037(3) 4780(2) 6467(5) 46(1) C(13) -919(3) 1899(2) 8918(4) 41(1) C(14) -1007(3) 1865(2) 10742(4) 34(1) C(15) 9(3) 1937(2) 11729(4) 41(1) C(16) -101(3) 1945(2) 13416(5) 47(1) C(17) -1195(3) 1885(2) 14130(5) 45(1) C(18) -2206(3) 1807(2) 13194(5) 44(1) C(19) -2111(3) 1795(2) 11500(4) 37(1) Table 87. Bond lengths [A] and angles [0] for 20. N(1)-C(1) 1.405(3) N(1)-B(1) 1.433(4) N(1)-C(13) 1.477(4) B(1)-C(4) l.510(5) B(1)-C(5) 1.534(4) C(1)-C(2) 1.377(5) C(1)-H(l) 0.96(3) C(2)-C(3) 1.382(5) C(2)-H(2) 1.00(3) C(3)-C(4) 1.390(5) C(3)-H(3) 1.02(3) C(4)-H(4) 0.82(3) C(5)-C(6) 1.208(3) C(6)-C(7) 1.450(3) C(7)-C(l2) 1.389(4) C(7)-C(8) 1.400(4) C(8)-C(9) 1.386(5) C(8)-H(8) 1.05(4) C(9)-C(l0) 1.375(5) C(9)-H(9) 0.89(3) C(10)-C(11) 1.373(5) C(l O)-H(l 0) 0.95(3) C(11)-C(12) 1.367(4) C(11)-H(l1) 0.99(3) C(12)-H(12) C(13)-C(14) C(13)-H(13A) C(13)-H(13B) C(14)-C(19) C(14)-C(15) C(15)-C(16) C(15)-H(15) C(16)-C(17) C(16)-H(16) C(17)-C(18) C(17)-H(17) C(18)-C(19) C(18)-H(18) C(19)-H(19) C(l)-N(1)-B(1) C(1 )-N(1 )-C(13) B(1)-N(1)-C(13) N(1)-B(1)-C(4) N(1)-B(1)-C(5) C(4)-B(1)-C(5) C(2)-C(1)-N(1) C(2)-C(1)-H(1) N(l)-C(l)-H(1) C(1)-C(2)-C(3) C(1)-C(2)-H(2) C(3)-C(2)-H(2) C(2)-C(3)-C(4) C(2)-C(3)-H(3) C(4)-C(3)-H(3) C(3)-C(4)-B(1) C(3)-C(4)-H(4) B(1)-C(4)-H(4) C(6)-C(5)-B(1) C(5)-C(6)-C(7) C(12)-C(7)-C(8) C(12)-C(7)-C(6) C(8)-C(7)-C(6) C(9)-C(8)-C(7) C(9)-C(8)-H(8) C(7)-C(8)-H(8) C(1O)-C(9)-C(8) C(10)-C(9)-H(9) C(8)-C(9)-H(9) C(11)-C(1O)-C(9) C(11)-C(10)-H(10) C(9)-C(10)-H(10) C(l2)-C(l1)-C(10) C(12)-C(11)-H(11) C(10)-C(11)-H(11) C(11)-C(12)-C(7) C(11)-C(12)-H(12) C(7)-C(12)-H(12) 0.96(3) 1.494(5) 1.03(3) 0.97(3) 1.386(4) 1.399(4) 1.384(5) 1.00(4) 1.359(5) 0.98(4) 1.370(5) 0.91(4) 1.389(5) 0.97(4) 0.92(4) 121.0(3) 115.1(3) 123.9(2) 116.9(2) 118.4(3) 124.7(3) 119.8(3) 118(2) 121(2) 122.5(3) 116.8(18) 120.7(18) 121.3(3) 116.8(19) 121.9(19) 118.3(3) 122(2) 120(2) 177.4(3) 177.1(3) 119.1(3) 121.0(3) 119.8(3) 119.2(3) 118.5(18) 122.2(18) 120.8(3) 126(2) 113(2) 119.6(3) 117(2) 124(2) 120.8(4) 116.2(18) 123.0(18) 120.5(3) 122.5(19) 117.0(19) 301 N(1)-C(13)-C(14) 114.7(3) N(1)-C(13)-H(13A) 105.3(17) C(14)-C(13)-H(13A) 108.6(17) N(1 )-C(13)-H(13B) 106.9(17) C(14)-C(13)-H(13B) 104.5(19) H(13A)-C(13)-H(13B) 117(2) C(19)-C(14)-C(15) 118.2(3) C(19)-C(14)-C(13) 120.5(3) C(15)-C(14)-C(13) 121.2(3) C(16)-C(15)-C(14) 120.2(4) C(16)-C(15)-H(15) 122.6(19) C(14)-C(15)-H(15) 117.2(18) C(17)-C(16)-C(15) 120.5(4) C(17)-C(16)-H(16) 118(2) C(15)-C(16)-H(16) 121(2) C(16)-C(17)-C(18) 120.6(4) C(16)-C(17)-H(17) 116(2) C(18)-C(17)-H(17) 124(2) C(17)-C(18)-C(19) 119.7(4) C(17)-C(18)-H(18) 119(2) C(19)-C(18)-H(18) 121(2) C(18)-C(19)-C(14) 120.8(4) C(18)-C(19)-H(19) 120(2) C(14)-C(19)-H(19) 119(2) Symmetry transfonnations used to generate equivalent atoms: 302 Table 88. Anisotropic displacement parameters (A2x 103)for 20. The anisotropic displacement factor exponent takes the form: -2p2[ h2a*2Ull + ... + 2 h k a* b* Ul2 ] UII U22 U33 U23 Ul3 Ul2 N(1) 40(1) 33(1) 35(1) -1(1) -5(1) 1(1) B(I) 38(2) 33(2) 30(2) 1(2) -8(2) -3(1) C(1) 51(2) 36(2) 51(2) 1(2) -3(2) -9(2) C(2) 76(3) 28(2) 71(2) -2(2) 4(2) -2(2) C(3) 60(2) 44(2) 59(3) -9(2) 2(2) 12(2) C(4) 47(2) 41(2) 48(2) -1(2) 8(2) 3(2) C(5) 35(1) 38(2) 39(2) 0(2) -7(2) -1(1) C(6) 35(2) 36(2) 33(2) 1(2) -4(1) 0(1) C(7) 38(2) 28(1) 37(2) 2(2) -7(1) 1(1) C(8) 54(2) 42(2) 57(2) 5(2) 17(2) 7(2) C(9) 78(3) 42(2) 59(2) -6(2) 15(2) 14(2) C(10) 80(3) 28(2) 54(2) -2(2) -5(2) -1(2) C(11) 56(2) 40(2) 58(2) -2(2) 11(2) -9(2) C(12) 50(2) 35(2) 54(2) -1(2) 9(2) 2(2) C(13) 38(2) 49(2) 36(2) 1(2) -3(2) 0(2) C(14) 40(2) 26(2) 34(2) 2(1) 3(1) 0(1) C(15) 36(2) 42(2) 45(2) 2(2) -3(2) -2(1) C(16) 52(2) 45(2) 42(2) 1(2) -10(2) -5(2) C(17) 66(3) 38(2) 32(2) 1(2) -2(2) 1(2) C(18) 46(2) 37(2) 49(2) 5(2) 7(2) 1(1) C(19) 36(2) 39(2) 35(2) 1(2) -5(2) 0(1) Table 89. Hydrogen coordinates ( x 104) and isotropic displacement parameters (A2x 103) for 20. x y z U(eq) H(1) -560(30) 390(20) 8700(40) 64(11) H(2) 970(20) -339(18) 7640(50) 61(9) H(3) 2660(30) 237(19) 6400(40) 64(10) H(4) 2730(30) 1633(18) 6430(50) 56(11) H(8) -280(30) 4573(19) 9070(40) 67(11) H(9) -60(30) 5880(20) 8970(40) 66(11) H(10) 1500(30) 6577(19) 7490(50) 64(9) H(11) 2740(30) 5825(19) 5790(40) 53(9) H(12) 2520(30) 4460(18) 5760(40) 50(9) H(13A) -850(30) 2480(20) 8570(40) 63(10) H(13B) -1610(30) 1609(16) 8530(40) 48(9) H(15) 800(30) 1958(18) 11170(40) 49(9) H(16) 600(30) 1987(19) 14120(50) 58(11) H(17) -1200(30) 1916(19) 15240(50) 52(11) H(18) -2980(30) 1789(18) 13730(50) 65(11) H(19) -2770(30) 1679(19) 10880(40) 60(11) Table 90. Torsion angles [0] for 20. 303 C(1 )-N(1 )-B(1 )-C(4) C(13)-N(1 )-B(1)-C(4) C(1 )-N(1 )-B(1)-C(5) C(13)-N(1 )-B(1)-C(5) B(1 )-N(1 )-C( 1)-C(2) C(13)-N( 1)-C( 1)-C(2) N(1 )-C(l )-C(2)-C(3) C(1)-C(2)-C(3)-C(4) C(2)-C(3)-C(4)-B(1 ) N (1 )-B(1 )-C(4)-C(3 ) C(5)-B(1 )-C(4)-C(3) N(1)-B(1)-C(5)-C(6) C(4)-B(1 )-C(5)-C(6) B(1)-C(5)-C(6)-C(7) C(5)-C(6)-C(7)-C(12) C(5)-C(6)-C(7)-C(8) C(12)-C(7)-C(8)-C(9) C(6)-C(7)-C(8)-C(9) C(7)-C(8)-C(9)-C(10) C(8)-C(9)-C(1O)-C(11) C(9)-C(1O)-C( II )-C( 12) C(10)-C(II)-C(12)-C(7) C(8)-C(7)-C(12)-C(11) C(6)-C(7)-C(12)-C(1I) C(I)-N(I )-C(13)-C(14) B(1 )-N(1)-C(13)-C(14) N(1)-C(13)-C(14)-C(19) N(1)-C(13)-C(14)-C(15) C(19)-C(14)-C(l5)-C(16) C(13)-C(l4)-C( 15)-C(16) -1.7(5) -180.0(3) 179.7(3) 1.4(5) -2.8(5) 175.6(3) 4.7(7) -1.8(7) -2.8(6) 4.4(6) -177.1(3) 151(8) -27(9) -29(14) 70(8) -108(8) -0.2(6) 178.1(3) 1.2(6) -1.7(6) 1.2(6) -0.2(6) -0.3(6) -178.5(3) 71.7(4) -109.9(4) -144.6(3) 38.2(4) -0.7(5) 176.6(3) C( 14)-C( 15)-C(16)-C(17) C( 15)-C(16)-C(17)-C(18) C(16)-C(17)-C(18)-C(19) C(17)-C(18)-C(19)-C(14) C(15)-C(14)-C(19)-C(18) C(13)-C(14)-C(19)-C(18) Symmetry transfonnations used to generate equivalent atoms: -0.1(5) 0.7(5) -0.5(5) -0.3(5) 0.9(5) -176.4(3) 304 305 APPENDIXB SYNTHESIS AND CHARACTERIZATION OF 1,2-DIHYDRO-l,2- AZABORINE B.t. Introduction Benzene and borazine are the prototypical organic and inorganic aromatic motifs, respectively. Hybrid aromatic compounds containing both BN and CC units, such as the 1,2-azaborine motif, have been studied since the late 1950s (see Chapter I), yet the synthesis and characterization of the simplest member of this class of heterocycle, 1,2- dihydro-l,2-azaborine 1, has been elusive. Dewar and co-workers reported an attempted synthesis of 1 in 1967,1 but ultimately concluded that it "seems to be a very reactive and chemically unstable system, prone to polymerization and other reactions."l Mild, efficient syntheses of 1,2-azaborines have recently been reported?,3 These protocols have led us to revisit the synthesis of the parent heterocycle 1. The isolation of 1 has permitted a direct comparison between benzene, borazine, and I ,2-dihydro-1 ,2- azaborine 1. D" V_r~e-l·me-"'-Iu .... £lAP I II IIlO:lI B.2.l. General All oxygen- and moisture-sensitive manipulations were carried out under an inert 306 atmosphere using either standard Schlenk techniques or a glove box. THF, Et20, CH2Ch, and pentane were purified by passing through a neutral alumina column under argon. Cyclohexene was dried over CaH2 and distilled under Nz prior to use. Solutions of Superhydride, tert-butyldimethylsilyl chloride, and boron trichloride were purchased from Aldrich and used as received. Trisacetonitrile(tricarbonyl)chromium(O) was purchased from Acros or Aldrich and used as received. Pd/C was purchased from Strem and heated under vacuum in a 100°C oil bath for 12 hours prior to use. Triphenylphosphine was purchased from TCl and used as received. Borazine was purchased from Gelest and used as received. All other chemicals and solvents were purchased (Aldrich or Strem) and used as received. Silica gel (230-400 mesh) was heated under vacuum in a 200°C sand bath for 12 hours. Flash chromatography was performed with this silica gel under an inert atmosphere. llB NMR spectra were recorded on a Varian Unityllnova 600 spectrometer at ambient temperature. IH NMR spectra were recorded on a Varian Unityllnova 300 or Varian Unityllnova 600 spectrometer. BC NMR spectra were recorded on a Varian Unity/lnova 300 or Varian Unityllnova 500 spectrometer. COSY and HETCOR NMR spectroscopy was performed on a Varian Unity/lnova 300 spectrometer. I1B NMR spectra were externally referenced to BF3·EtzO (6 0). lR spectra were recorded on a Nicolet Magna 550 FT-lR instrument with OMNlC software. UV-Vis spectra were recorded on an Agilent 8453 spectrometer with 307 ChemStation software. High-resolution mass spectroscopy data were obtained at the Mass Spectroscopy Facilities and Services Core of the Environmental Health Sciences Center at Oregon State University. Financial support for this facility has been furnished in part by the National Institute ofEnvironmental Health Sciences, NIH (P30 ES002l0). B.l.l. Supplemental information for Chapter III, section 3.3 Electronic Structure Calculations. The electronic structure calculations were done at different levels as follows. The heat of formation of c-C4BNH6 (1) was calculated using a composite approach4-9developed for the prediction of the thermodynamic properties of molecules based on molecular orbital theory using coupled cluster methods at the CCSD(T)IO (coupled cluster with single and double excitations with an approximate triple corrections) level extrapolated to the complete basis set level with the correlation consistent basis setsll,12 using equation (1) where n = 2 (aug-cc-pVDZ), 3 (aug-cc-pVTZ), and 4 (aug-cc-pVQZ), as proposed by Peterson et alY E(n) = ECBS + A exp[-(n-l)] + B exp[-(n-l)2] (1) Additional corrections were included: (l) core-valence correlation effects at the CCSD(T)/cc-pwCVTZ level;14,15 (2) scalar relativistic effects at the CCSD(T)/Douglas- Kroll-Hess level with the cc-PVTZ-DK basis set;16-19 and atomic spin orbit from experimental atomic excitation energies.2° The vibrational frequencies and geometries were calculated at the MP2/cc-pVTZ level.21 The B-H, C-H and N-H frequencies were scaled by the ratio A-HexptIA-Hcalc for the molecules BH3, CH4 and ]'.JH3.22,23 We also calculated heats of formation at the computationally cheaper G3MP2 level for use in the 308 resonance energy calculations?4 By combining our computed LDovalues with the known heats of formation25 at 0 K for the elements ~H/(H) = 51.63, ~Hfo(B) = 135.1 ± 0.2, ~Hf°(N) = 112.53, and ~Hf°(N) = kcal/mol, we can derive ~Hi values for the molecules under study in the gas phase. The heat of formation of the boron atom was taken from Karton and Martin.26 We obtain heats of formation at 298K by following the procedures outlined by Curtiss et at?? The geometries and vibrational frequencies of the Cr(CO)3 complexes were calculated at the density functional theory (DFT) B3LYP/DZVP21evel.28-3o The NMR chemical shift calculations were obtained at the DFT B3LYP level with the Alhrichs- vtzp basis set31 using the GIAO fo~alism32 to treat the gauge invariance problem. The nucleus-independent chemical shifts (NICS)33 were calculated at the approximate center of the rings and at 1 A and 2 A above the ring on the axis perpendicular to the ring and passing through the approximate center of the ring. The excitation energies and oscillator strengths for C-C6H6, c-C4BNH6and c-B3N3H6 were calculated with time dependent DFT (TD_DFT)34-36 and the B3LYP/aug-cc-pVDZ//MP2/cc-pVTZ and B3LYP/aug-cc-pVTZ//MP2/cc-pVTZ levels, and with equations ofmotion3? CCSD (EOM-CCSD/aug-cc-pVDZIIMP2/cc-pVTZ) level. DFT and MP2 calculations were carried out using Gaussian-03,38 coupled cluster calculations using MOLPRO-2006,39 and TD-DFT using NWChem.4o The electrostatic potential (ESP) is obtained by rolling a positive point charge over a density contour. The ESP was calculated at the B3LYP/6-311 +G** level with the program system Spartan.41 309 Survey ofN-Benzyl cleavage. Compound 4 was observed in entries 1-3 in Table 1. 4: IH NMR (600 MHz, C6D6): [) 7.42 (d, 3JHH = 7.0 Hz, 2H), 7.0-7.2 (m, 8H), 4.19 (s, 2H), 2.65 (t, 3JHH = 5.4 Hz, 2H), 1.5-1.6 (m, 4H), 1.20 (m, 2H). lIB NMR (192.5 MHz, C6D6) [) 43.2. Entry 1: Compound 2 (0.050 g, 0.20 mmol), PdlC (10 wt% Pd, 0.043 g, 0.041 mmol), and C6D6 (1 mL) were combined in a sealed high-pressure reaction vessel. The vessel was charged with H2(40 psi) and heated to 80°C for 6h. IH NMR indicated that compound 4 was formed in a 1: 1 ratio with unreacted 2. Entry 2: Compound 2 (0.050 g, 0.20 mmol), PdlC (10 wt% Pd, 0.022 g, 0.021 mmol), and C6D6 (1 mL) were combined in a sealed high-pressure reaction vessel. The vessel was charged with H2(40 psi) and heated to 60°C for 6h. IH NMR indicated that compound 4 was formed in a 40:60 ratio with unreacted 2. Entry 3: Compound 2 (0.050 g, 0.20 mmol), PdlC (10 wt% Pd, 0.043 g, 0.041 mmol), and THF-ds (1 mL) were combined in a sealed high-pressure reaction vessel. The vessel was charged with 1 atm ofH2 (flushed for 1 minute with a steady stream ofH2) and heated to 80°C for 14h. Compound 4 was the only identifiable species in the IH NMR spectrum. Entry 4: Compound 2 (0.050 g, 0.20 mmol), Pd(OH)2/C (20 wt% Pd, 0.015 g, 0.02 mmol), and EtOH (2 mL) were combined in a sealed high-pressure reaction vessel. The vessel was charged with H2 (50 psi) and stirred at 25°C for 4 h. Solvent was removed and the crude reaction mixture was redissolved in C6D6. Compound 2 was the only identifiable species in the IH NMR spectrum. 310 Entry 5: Compound 2 (0.010 g, 0.041 mmol), PdlC (10 wt% Pd, 0.005 g, 0.005 mmol), HC02H (0.1 mL), and MeOH (2.1 mL) were combined in a flask and stirred at rt for 48 h. liB NMR indicated the formation of 4-coordinate boron (6 19 ppm); numerous unassigned peaks were observed in the IH NMR spectrum. Entry 6: Compound 2 (0.010 g, 0.041 mmol), TMSI (0.2 mL), and CD2Ch (1 mL) were combined in a vial and heated at 60°C for 2h. MeOH (0.05 mL) was then added and the vial was heated at 60°C for an additional 2 h. Compound 2 was the only identifiable species in the IH NMR spectrum. Entry 7: Compound 2 (0.045 g, 0.184 mmol), DDQ (0.042 g, 0.184 mmol), and pentane (1 mL) were combined in a vial and heated at 75°C for 4h. Solvent was removed and the crude mixture was redissolved in CD2Ch. Compound 2 was the only identifiable species in the 1H NMR spectrum. Entry 8. Compound 2 (0.010 g, 0.041 mmol), ceric ammonium nitrate (0.047 g, 0.086 mmol), MeCN (1 mL), and H20 (0.2 mL) were combined in a vial and stirred at rt for 4 h. Compound 2 was the only identifiable species in the IH NMR spectrum. Compound 5. Tributylallyl tin (4.068 g, 12.29 mmol) was added to a solution of BCh (1.0 M in hexanes; 10 mL, 10 mmol) at -78°C under N2• The reaction was slowly warmed to rt and stirred for 30 min. The reaction was cooled to -78°C, whereupon TMS- allylamine (1.29 g, 10 mmol) was added dropwise. The reaction was then warmed to rt and stirred for 4h. The flask was then cooled to -78°C and NEt3 (1.66 mL, 12 mmol) was added. The flask was warmed to rt and stirred for 4 h. Solids were then filtered through an Acrodisc and solvents removed under reduced pressure. 1H and lIB NMR were 311 consistent with the formation of 5, however vacuum distillation (49-60 cC, 200 mT) provided 5 as a mixture of compounds, including tributyltin chloride. IH NMR (300 MHz, C6D6): () 5.6-6.2 (br m), 4.9-5.2 (br m), 3.6 (br m), 2.2 (br m), 0.30 (s). liB NMR (192.5 MHz, C6D6): () 43.1. Compound 6. Allylphenylboron chloride2 (0.700 g, 4.3 mmol) and CH2Cl2 (4 mL) were combined in a flask and cooled to -78 cc under Nz, whereupon TIPS-allylamine (0.909 g, 4.3 mmol) was added dropwise with stirring. The mixture was stirred for 1 h, at which point Net3 (0.711 mL, 5.1 mmol) was added dropwise. The solution was allowed to warm to rt and was stirred for 48 h. Solids were then filtered and the solvent removed. Vacuum distillation (50-71 cC, 10 mT) provided 6 as a clear, colorless liquid (0.352, 24%). IH NMR (300 MHz, CDzClz): () 7.2-7.4 (br m, 5H), 5.6-5.8 (br m, 2H), 4.8-5.0 (br m, 4H), 3.8 (br m, 2H), 1.8 (br m, 2H), 1.0-1.3 (br, 18H). liB NMR (192.5 MHz, CDzCh): () 46.3. Compound 8. In a glove box, allyltriphenyl tin (28.6 g, 73.1 mmol) was dissolved in 200 mL CHzClz and cooled to -78°C under nitrogen. A solution ofBCh (1.0 M in hexanes; 73.1 mL, 73.1 mmol) was then added dropwise maintaining vigorous stirring at all times. The reaction was stirred at -78°C for 4 h, whereupon TBS-allyl amine (12.5 g, 73.1 mmol in 20 mL pentane) was then added to the reaction flask. After 20 minutes, NEt3 was added dropwise and the reaction was allowed to warm to rt and stirred for 12 h. At the conclusion ofthe reaction, approximately one-half of the solvent was removed under vacuum, and 200 mL pentane was added. The reaction mixture was filtered through a 312 medium-porosity frit, and the filtrate was concentrated under reduced pressure. Vacuum distillation (60-75 °C, 300 mTorr) afforded 8 as a clear, colorless liquid (10.8 g, 58%). IH and l3C NMR were consistent with the formation ofrotamers in a 1:1 ratio. IH NMR (600 MHz, CD2Cb): 65.85 (br, 2H), 5.0 (br, 4H), 3.92 (br s, 1H), 3.80 (br s, 1H), 2.08 (br s, 1H), 2.00 (br s, 1H), 0.93 (s, 9H), 0.28 (s, 6H). l3C NMR (75.4 MHz, CD2Cb): 6138.5, 136.3, 136.1, 115.0, 114.5,51.4,50.4,30 (br), 27.5, 27.1, 20.5, 20.1, -1.46,- 1.53. llB NMR (192.5 MHz, CD2Ch): 643.0. FTIR (thin film) 3079, 2956, 2931, 2886, 2859,1634,1466,1382,1340,1324,1257,1210,1101, 1074, 1043, 1006,994,959,903, 839, 785, 743, 679, 575, 554 em-I. HRMS (EI) calcd for C12H2sBCINSi (M+) 257.15378, found 257.15316. Compound 9. In a glove box, a solution of Grubbs 1st generation catalyst (2.08 g, 2.52 mmol in 40 mL CH2Ch) was added to a stirring solution of aminoborane 8 (32.44 g, 126.2 mmol in 400 mL CH2Ch). The solution was stirred at rt for 30 min, after which the solvent was removed. The product was distilled under reduced pressure (50-55°C, 50 mTorr) to give the desired ring-closed compound 9 and isomer 9' in a 1:0.9 (9:9') ratio as a clear, colorless liquid (23.62 g, 82%). IH NMR (600 MHz, CD2Ch): 66.78 (d, 3JHH = 11.7 Hz, 1H (9')),5.80 (dt, 3JHH = 8.5, 1.7 Hz, 1H (9')), 5.76 (br, 1H (9)),5.60 (m, 1H (9)),3.74 (m, 2H (9)),3.16 (t, 3JHH = 6.6 Hz, 2H (9')), 2.19 (m, 2H (9')), 1.70 (br, 2H (9)),0.97 (s, 9H), 0.95 (s, 9H), 0.33 (s, 6H), 0.31 (s,6H). l3C NMR (125 MHz, CD2Ch): 6148.5, 130 (br), 125.7, 125.3,48.8., 45.6,29.8,27.5,27.2,21 (br), 20.6,20.0, -1.5, -1.9. liB NMR (192.5 MHz, CD2Ch): 642.1 (9),36.7 (9'). FTIR (thin film) 3027, 2930, 2858, 1670, 1599, 1463, 1424, 1362, 313 1306,1255,1198,1177,1147,1074,1008,959,886,824, 780, 730, 707,685,671,641, 588,531,462,417 em-I. Compound 10. A 500 mL Schlenk tube was charged with 9(9') (14.04 g, 61.13 mmol), Pd/C (10 wt%; 9.76 g, 9.17 mmol), and cyclohexene (150 mL). The suspension was stirred at 100°C for 16 h, cooled to rt and filtered through a medium-porosity frit. The resulting filtrate was cooled to -78°C, and a solution ofphenylethynylmagnesium bromide (1.0 M solution in THF; 6.1 mL, 6.1 mmol) was then added. The mixture was allowed to warm to rt and passed through an Acrodisc. The resulting filtrate was concentrated under reduced pressure. Vacuum distillation (52-55°C, 50 mTorr) gave 1,2- azaborine 10 as a clear, colorless liquid (4.79 g, 35%). IH NMR (600 MHz, CH2Ch): 67.56 (dd, 3JHH = 6.1,3.6, 1H), 7.28 (d, 3JHH = 6.3 Hz, 1H), 6.61 (d, 3JHH = 11.2 Hz, 1H), 6.33 (dd, 3JHH = 6.6,4.9 Hz, 1H), 0.94 (s, 9H), 0.56 (d,6H). B C NMR (75 MHz, CD2Ch): 6 145.8, 139.2, 129 (br), 112.0,26.9, 19.7, -1.4. liB NMR (192.5 MHz, CD2Ch): 635.0. FT1R (thin film) 3072,3034,2931,2885,2860, 1606,1508,1471,1450,1388,1364,1265,1237,1214, 1153, 1111, 1044, 1025,980,938, 823, 788, 740, 716, 683, 669, 619, 575 em-I. HRMS (E1) calcd for ClOHI9BNSiCl (M+) 227.10684, found 227.10680. Compound 11. To a stirred solution of 1,2-azaborine 10 (4.785 g, 21.08 mmol in 100 mL EhO) was added dropwise a solution of LiHBEt3 (1.0 M in THF; 22.1 mL, 22.1 mmo1) at -78°C. The solution was warmed to rt and stirred for 6 h. The mixture was then passed through an Acrodisc and concentrated under reduced pressure. The crude material was purified by silicage1 chromatography (pentane as eluent) to furnish 11 as a clear, 314 colorless liquid (4.035 g, 99%). IH NMR (600 MHz, CDzClz): () 7.65 (dd, 3JHH = 5.4, 4.0 Hz, 1H), 7.40 (d, 3JHH = 6.4 Hz, 1H), 6.88 (d, 3JHH = 10.8 Hz, 1H), 6.43 (t, 3JHH = 6.6 Hz, 1H), 5.1 (br q, IJBH = 141 Hz, 1H), 0.90 (s, 9H), 0.46 (s, 6H). BC NMR (75 MHz, CDzCh): () 144.2, 138.5, 130 (br), 113.2,26.3, 18.4, -3.9. lIB NMR (192.5 MHz, CDzCh): () 33.9 (d, IJBH = 125 Hz). FTlR (thin film) 3067, 3029, 2956, 2859, 2530, 1603, 1533, 1504, 1471, 1391, 1363, 1270, 1160, 1141, 1021,939,927,885,840, 784, 736, 697, 655, 603, 574 em-I. HRMS (El) calcd for ClOHzoBNSi (M+) 193.14581, found 193.14566. Compound 12. 1,2-Azaborine 11 (0.162 g, 0.839 mmo1), trisacetonitrile(tricarbonyl)chromium(O) (0.326 g, 1.26 mmol), and THF (10 mL) were combined in a 25 mL Schlenk tube and heated at 60°C for 16 h. The mixture was concentrated under reduced pressure, and the resulting crude material was purified by silica gel chromatography (pentane/EtzO as eluent) to afford complex 12 as an orange-red solid (0.197 g, 71%). IH NMR (600 MHz, CDzClz): () 6.03 (d, 3JHH = 4.6 Hz, IH), 5.93 (dd, 3JHH = 6.3, 3.0 Hz, 1H), 5.28 (t, 3JHH = 4.9 Hz, 1H), 4.63 (d, 3JHH = 9.3 Hz, IH), 3.7 (q, br, IJBH = 164 Hz, 1H), 0.88 (s, 9H), 0.40 (s, 3H), 0.37 (s, 3H). BC NMR (75 MHz, CDzCh): () 230.7, 108.8, 103.9,86 (br), 84.2, 26.2, 19.0, -3.3, -6.0. lIB NMR (192.5 MHz, CDzCh): () 17.2 (d, IJBH = 102 Hz. FTlR (thin film) 2955, 2937, 2862, 1976, 1912, 1870, 1507,1464,1443,1365,1261,1200,1109, 1012,932,882,846,788,697,669,634,604, 536 em-I. HRMS (El) calcd for C13HzoBN03SiCr (Ml329.07107, found 329.07120. 1,2-Dihydro-l,2-azaborine tricarbonylchromium(O) (13). To a stirred solution -------------------- - ----- --- 315 of complex 12 (4.67 g, 14.2 mmo1 in 100 mL THF) was added dropwise a solution ofHF- pyridine (0.1 M solution in THF of 70 wt% HF; 28.4 mL, 14.2 mmol) at -20 0. The reaction was maintained at -20°C, with occasional stirring, for 3 h, and then it was wanned to rt and stirred 1 h. The mixture was concentrated under reduced pressure, and the resulting crude material was purified by column chromatography (pentanelEt20 as eluent) to yield complex 13 as an orange solid (2.31 g,76%). IH NMR (600 MHz, CD2C12): [) 6.19 (t, 3JHH = 5.3 Hz, 1H), 5.85 (dd, 3JHH = 6.4, 2.7 Hz, 1H), 5.38 (br t, IJNH = 48.2 Hz, 1H), 5.31 (ddd, 3JHH = 5.3, 1.3,0.9 Hz, 1H), 4.70 (dd, 3JHH = 8.3, 1.2 Hz, 1H), 3.6 (br q, IJBH = 133 Hz, 1H). BC NMR (75 MHz, CD2Ch): [) 230.1, 108.5,99.4,86 (br), 82.9. liB NMR (192.5 MHz, CD2Ch): [) 15.4 (d, IJBH = 144 Hz. FTIR (CH2Ch) 3371, 2583, 1975, 1898 cm- I . UV Amax(pentane) 215 nm. HRMS (El) calcd for C7H6BN03Cr (M+) 214.98459, found 214.98510. 1,2-Dihydro-l,2-azaborine (1). Complex 13 (0.150 g, 0.698 mmol), triphenylphosphine (0.915 g, 3.49 mmol), and isopentane (3.0 mL) were combined under N2 atmosphere in a Schlenk tube and sonicated at rt for 3 h. Isopentane and 1 were transferred under vacuum to a cold trap at -78°C. Residual isopentane was removed under vacuum to provide 1 as a clear and colorless liquid upon wanning to rt. IH NMR (CD30D) of this liquid in the presence of hexamethylbenzene as an internal standard (1 mL; 1 mM hexamethylbenzene) indicated a yield of 0.006 g (10%). IH NMR (600 ~Hz, CD2Cb): [) 8.44 (t, IJNH = 57.4 Hz, 1H), 7.70 (br t, 1H), 7.40 (t, 3JHH = 6.5 Hz, 1H), 6.92 (d, 3JHH = 10.7 Hz, 1H), 6.43 (t, 3JHH = 6.3 Hz, 1H), 4.9 (br q, IJBH = 128.2 Hz, 1H). BC NMR (75 MHz, CD2Ch): [) 144.5, 134.7, 131.6, 112.1. llB 316 NMR (192.5 MHz, CD2Ch): () 31.0 (d, IJBH = 131 Hz). FTIR (thin film) 3398, 3027, 3008,2525, 1613, 1533, 1453, 1427, 1350, 1216, 1162, 1109,894,820, 715,579 em-I. VV Amax (pentane) 269 nm. HRMS (EI) calcd for C4H6BN (M+) 79.059330, found 79.059269. Melting point = -46 to -45 °C. IH NMRyield of 1. Complex 13 (0.0105 g, 0.0469 mmol) and triphenylphosphine (0.0660 g, 0.252 mmol) were combined in a J. Young NMR tube, to which was added a solution of hexamethylbenzene in CD2Ch (1.0 mL; 0.65 mM hexamethylbenzene). At t = 1.5 h, IH NMR indicated the formation of 1 in 84% yield (integration versus hexamethylbenzene). Isolation of 1 via the addition of 1,6-dicyanooctane to 13. Complex 13 (# g, # mmol) and 1,6-dicyanooctane (# mL) were combined in a flask and stirred for 24 h at rt. Heterocycle 1 was isolated in 53% yield (# g) via vacuum transfer to a cold trap at -78°C. Thermal stability of 1. Hexamethylbenzene (0.0030 g, 0.018 mmol) was added to a solution of 1,2-dihydro-l,2-azaborine 1 (0.7 M in CD2Ch; 0.4 mL) in a 1. Young NMR tube. The tube was sealed and heated to 60°C for 72 h. IH NMR integration of 1 versus hexamethylbenzene indicated no degradation of 1. COSy NMR Spectrum of 1,2-Dihydro-l,2-azaborine (1). STAlf[lAIW lH 06SERVf Pu1'5e Sequence: rel.n.,yh Sol .... enl: COlCll AIl!llcfll tl'H"pe",lturc ]UOVA-300 "nlllr300" 317 Reli\"l. Llela~' l,OOO s~c COS:y 90-90 Acq. ti. ... ~ 1).132 sec Vilith Bol2.!' Hz 20 lJicltil 19,12.~ Hz "I repetitions 2~6 jnc"crtellt~ OBSERVE HI. Z!l9.9;:l3101>6 JoiHl DATA PROCESSHlG S1ne bElll 0.0&6 sec n DATA PROCES$.rUl; S1ne ben I). Oll ';I'lC FT size l02~ )I 11124 Tot;)l t1mc ;>1) ~1n. 45 F2 ( ppm)' 3.5 4.0 4.5 f , 5.0 5.5 6.0 6.5 1.0 1.5 8.0 I 8.S 9.0 t.' .J1 I 9.0 8.5 8.0 1.5 7.0 6.5 6.0 5.5 F 1 (ppm) 5.0 4.5 4.0 3.5 318 HETCOR NMR Spectrum of 1,2-Dihydro-l,2-azaborine (1). ?ulse \'I~IlUCnCl!' h~'-tOI SL'lvenl; ClIle1.' 1IJ\llienl teOlp[>r,lture Il.OVA-30~ "rl""30:" Re 1..,.. de l .... y ... J ~ 0 Silt /Itt]. t1llle 0 > ~li;" ~e( \ljilth 16~OI.1 II;: ,W IJltHh !Hl.l til 2:~O r[>pC1UtlJllt: 6~ Inc.J"'.,illlllnB O~SE'RVE Clj. J§~laU~7 )01112 QI:.COUPLI:. HI, l1'J. ~:U'16U HIL! PO'B;'IH 32 dl\ on iJur:in~ "l:lllll~(tlon cdr (((".lug delay IJroUl-1 r. .od\l \ll~ed IIM:I "P'OCESSHlG Line lJrDuiJ(llllng 1,0 HZ 1'1 II,HI\, PROC~SSIlltl Lint lJrD31!elllno O,iI Hz ~T ~j,[> ~048 ~ 5L2 TOt,).t ll",e 1 tlr, ~8 ",III, ,H ~IJC ! I I! . -~--~---'-"'--'---------"------ f1 ( ppmj 4.0 4.5 S.O 5.5 6.0 6.5 ) 1.0 7,5 .J B.O .. J 8.5 I 9.0\ I ?OO 180 160 140 IZO 100 80 F2 (ppm) 60 40 ZO Electronic Structure Calculations Results. The NICS and NMR chemical shift calculations are given in Table 1. The structures and labels are shown in Figures 1 and 2. The calculated electronic spectra are given in Table 2. The calculated spectra with the two different approaches are in reasonable agreement with each other. The calculated spectra show that the first band for c-BNC4H6 is predicted to be quite intense and red shifted with respect to the predicted intense bands in c-C6H6 and c-B3N3H6. The bands in c-B3N3H6 are substantially blue-shifted in comparison to C-C6H6' The calculated infrared frequencies are in Table 3. The scaled calculated value for c-BNC4H6 for the 319 N-H stretch is within 30 cm-1 of the experimental value, the scaled B-H stretch is within 8 cm-1 of experiment and the C-H stretches are within 40 cm-1 of experiment. The total CCSD(T) electronic energies in a. u. as a function of basis set extrapolated to the complete basis set limit are given in Table 4 and the components for the atomization energies in kcallmol are given in Table 5 for c-BNC4H6 and C-B3N3H6. The calculated heats of formation are given in Table 6 and should be good to ± 1.5 kcal/mol for c-BNC4H6on the basis of our previous calculations on benzene. The DFT R-Cr(CO)3 bond dissociation energies are given in Table 7. The binding energies for R = C-C6H6 and R = c-BNC4H6 are comparable whereas the binding energy for R = c-B3N3H6 is substantially lower. There are many ways to define the resonance stabilization energy (RSE) as it represents an energy stabilization with respect to a model system.42 The "resonance" or "delocalization" energy is totally dependent on the definition of the model. For benzene, one could use the dehydrogenation reaction (1) in Table 8 and compare it to the same reaction for 3 ethylene molecules (Reaction (4) in Table 8). This gives an effective RSE of 48 kcal/mol at the G3MP2 level and 50.4 kcal/mol at the best level.43-45 This RSE is larger than usually expected because C2H4 is not the right structure. The correct model is to dehydrogenate cyclohexane and make 3 C=C bonds and 3 C-C Sp2 sigma bonds. The RSE calculated in this way for c-BNC4H6 is given by the comparison of reactions (2) and (5) in Table 8 and is 30.9 kcal/mol. For C-B3N3H12, reactions (3) and (6) give RSE's near 0 kcallmol in this model. Thus the ordering is the same as given in the paper. An improved way to estimate the resonance energies would be to compare the 320 difference in the energies of reactions (7) and (8). In this case we obtain an RSE of 32.2 kcal/mol for c-C6H6. The situation for c-C4BNH6is more complicated. We start from the diene containing a B=N bond and one of two C=C bonds as shown in reactions (9) and (11). The difference in energies between reactions (9) and (10) gives an RSE of 21 kcallmol and between reactions (11) and (12) gives an RSE of 18.3. This provides an estimate of RSE (c-C4BNH6) = 20 ± 2 kcal/mol, which is about 12 kcal/mol below that of benzene. This same approach gives a somewhat higher estimate for the RSE (c- B3N3H6) = 25.8 kcal/mol from reactions (13) and (14). The exchange reaction (15) is consistent with benzene having a resonance energy about 14 to 15 kcal/mollarger than that of c-BNC4H6. The exchange reactions (16) and (17) have been used to define the RSE of benzene and give comparable values. Use of similar exchange reactions suggests that the RSE of c-C4BNH6 is 12 to 13 kcal/molless than that of benzene consistent with all of the above energies. We note that use of this approach for the definition ofRSE (c-B3N3H6) gives larger values than might be expected due to the different energies of the cr(Sp2_Sp2) bonds being formed. The change in the cr(Sp3_Sp3) bond to the cr(Sp2_Sp2) for a C-C bond is about 15 kcal/mol whereas for a B-N bond it is about 84 kcal/mo1.46 The reactions to form acetylene or HBNH are all very endothermic and the results for reactions (22) and (23) are consistent with benzene having larger RSE than c-BNC4H6 • The calculated geometry parameters are given in Tables 9 and 10. The calculated electrostatic potential maps are given in Figure 3. 321 NICS and NMR Chemical Shift Calculations. See the Table 1 for NICS and NMR chemical shift calculations. Table 1. NICS at 0, 1, and 2 A and NMR at the B3LYPIAlhrichs-vtzp level of calculation. Molecule NICS(O) NICS(l) NICS(2) Atom ~ (ppm) c-C6H6 -8.76 -10.39 -2.57 C 135.2 H 7.5 c-BNC4H6 -5.62 -7.27 -3.89 Bl 26.9 N2 -246.9 C3 140.2 C4 118.8 C5 151.5 C6 139.0 H7 5.4 H8 7.8 H9 7.3 HI0 6.6 Hll 8.0 Hl2 7.4 c-B3N3H6 -2.02 -3.01 -1.59 B 26.1 N -287.6 H (from BH) 5.0 H (fromNH) 5.3 Calculated Electronic Spectra: See the following tables for calculated electronic spectra. Table 2. Excitation energy and oscillator strength for C6H6, C4BNH6 and B3N3H6 cycles calculated with TD-DFT at the B3LYP/aug-cc-pVDZ//MP2/cc-pVTZ and B3LYP/aug-cc-pVTZIIMP2/cc-pVTZ levels, and with EOM-CCSD/aug-cc-pVDZ//MP2/cc-pVTZ level. C-C6H6: B3LYP/aVDZa AE Osc strength(nm)State I)A 2_ IA 3_ IA 4_ IA 5)A 6_ IA 7)A 8_ IA 9_1A AE (eV) 5.40 6.07 6.36 6.36 6.96 6.96 6.98 7.02 7.02 230 205 195 195 178 178 178 177 177 0.00000 0.00000 0.00000 0.00000 0.58378 0.58378 0.06381 0.00000 0.00000 322 10)A 7.09 175 0.00000 I)A 3.83 324 2_3A 4.71 263 3)A 4.71 263 4_3A 5.07 245 5)A 6.32 196 6)A 6.32 196 7)A 6.91 180 8)A 6.99 177 9)A 6.99 177 10-3A 7.08 175 C-C6H6: B3LYP/aVTZa AE (eV) AE Osc strength(nm) I)A 5.39 230 0.00000 2)A 6.05 205 0.00000 3)A 6.30 197 0.00000 4_ IA 6.30 197 0.00000 5)A 6.89 180 0.05878 6_ IA 6.92 179 0.00000 7)A 6.92 179 0.00000 8_1A 6.94 179 0.58183 9- IA 6.94 179 0.58184 lO)A 6.98 178 0.00000 1_3A 3.81 326 2-3A 4.70 264 3)A 4.70 264 4_3A 5.05 246 5)A 6.26 198 6_3A 6.26 198 7-3A 6.82 182 8_3A 6.90 180 9)A 6.90 180 lO)A 6.98 178 C-C6H6: CCSD/aVDZb State AE (eV) AE Osc strength(nm) I)A 5.20 238 0.00000 2_ IA 6.48 191 0.00000 3)A 6.48 191 0.00000 4_ I A 6.55 190 0.00000 5)A 7.03 177 0.07141 323 6_1A 7.10 175 0.00000 7)A 7.10 175 0.00000 8)A 7.21 172 0.00000 9_1A 7.74 160 0.00000 10)A 7.75 160 0.00000 c-BNC4H6: B3LYP/aVDZ3 State AE (eV) AE Osc strength(nm) l)A 5.01 248 0.16423 2)A 5.32 233 0.00000 3)A 5.89 211 0.07045 4_1A 6.05 205 0.00020 5)A 6.17 201 0.00151 6_1A 6.31 197 0.03727 7)A 6.65 187 0.12739 8_ 1A 6.79 183 0.00434 9_1A 6.90 180 0.00031 10-1A 6.91 179 0.00005 l)A 3;23 384 2_3A 4.42 281 3)A 4.79 259 4_3A 5.28 235 5)A 5.80 214 6_3A 6.02 206 7)A 6.27 198 8)A 6.33 196 9_3A 6.62 188 10)A 6.69 186 c-BNC4H6 : B3LYP/aVTZ3 State AE (eV) AE Osc strength(nm) 1_1A 4.99 248 0.16466 2_1A 5.27 236 0.00000 3)A 5.87 211 0.07068 4_1A 5.95 208 0.00013 5_1A 6.17 201 0.00430 6_1A 6.21 200 0.02983 7_ 1A 6.56 189 0.08839 8_ 1A 6.67 186 0.00318 9_ I A 6.79 183 0.00030 lO-IA 6.88 180 0.00050 l)A 3.21 387 2)A 4.42 281 324 3)A 4.78 260 4)A 5.23 237 5)A 5.79 214 6)A 5.94 209 7)A 6.17 201 8)A 6.32 196 9-3A 6.58 188 10-3A 6.62 187 c-BNC4H6: CCSD/aVDZb State AE (eV) AE Osc strength(nm) I-lA' 5.06 245 0.16373 2)A' 6.22 199 0.08806 3- IA' 6.63 187 0.05292 4)A' 7.46 166 0.48962 5)A' 7.82 159 0.28552 1_ IA" 5.52 225 0.00001 2)A" 6.19 200 0.00001 3)A" 6.42 193 0.04674 4_ IA" 6.88 180 0.00180 5)A" 6.90 180 0.00220 c-B3N3H6: B3LYP/aVDZ8 State AE (eV) AE Osc strength(nm) l)A 6.62 187 0.00000 2_ IA 7.10 175 0.00000 3)A 7.10 175 0.00000 4_ IA 7.21 172 0.00000 5)A 7.53 165 0.33435 6_ IA 7.53 165 0.33435 7_ IA 7.53 165 0.01659 8_ IA 7.60 163 0.08702 9_ IA 7.68 161 0.00000 10)A 7.68 161 0.00000 1_3A 5.98 207 2)A 6.24 199 3)A 6.24 199 4)A 6.37 195 5)A 6.99 178 6-3A 6.99 178 7)A 7.04 176 8)A 7.26 171 9)A 7.26 171 325 0.00000 0.00000 0.00000 0.00000 0.33185 0.33185 0.01514 0.08347 0.00000 0.00000 State l_ IA 2_ IA 3)A 4_ LA 5- I A 6- I A 7)A 8_ I A 9_ IA lO)A I)A 2)A 3)A 4)A 5)A 6_3A 7)A 8)A 9-3A 10)A 10-3A 7.39 168 c-B3N3H 6 : B3LYP/aVTZa AE AE (eV) (nm) Osc strength 6.63 187 7.10 175 7.10 175 7.21 172 7.52 165 7.52 165 7.52 165 7.60 163 7.67 162 7.67 162 6.01 206 6.25 198 6.25 198 6.37 195 6.99 177 6.99 177 7.02 177 7.25 171 7.25 171 7.38 168 c-B3N3H6: CCSD/aVDZb State AE (eV) AE (nm) Osc strength I)A' 6.74 184 0.00000 2)A' 7.93 157 0.43339 3_ IA' 7.93 157 0.43339 4)A' 8.05 154 0.00086 5)A' 8.05 154 0.00085 I)A" 7.17 173 0.00000 2)A" 7.17 173 0.00000 3_ I A" 7.55 164 0.07268 4)A" 7.99 155 0.00000 5- IA" 7.99 155 0.00000 a Calculations done on C1 symmetry. b Calculations done on C" symmetry. Calculated IR Stretching Frequencies: See Table B3 for calculated IR stretching frequencies compared to experimentally determined values. Table 3. Scaling for C-H, N-H, and B-H stretching vibrational modes for C6H6, NH3, and BH3• Scaled MP2/cc-pVTZ vibrational modes and comparison with the experiment. 326 Molecule Mode type MP2/cc-pVTZ Expt Scaling Total scaling C6H6 0.9495 C-H 3239.6 3068.0 0.9470 C-H 3229.7 3063.0 0.9484 C-H 3229.7 3063.0 0.9484 C-H 3213.1 3062.0 0.9530 C-H 3213.1 3047.0 0.9483 C-H 3201.5 3047.0 0.9517 NH3 0.9443 N-H 3514.2 3337.0 0.9496 N-H 3657.3 3444.0 0.9417 N-H 3657.3 3444.0 0.9417 BH3 0.9478 B-H 2608.2 2475.0 0.9489 B-H 2746.5 2601.6 0.9472 B-H 2746.5 2601.6 0.9472 BNC4H6 N-H 3628.9 0.9443 3426.8 C-H 3253.9 0.9495 3089.5 C-H 3228.8 0.9495 3065.6 C-H 3212.4 0.9495 3050.1 C-H 3181.8 0.9495 3021.0 B-H 2672.2 0.9478 2532.7 1659.9 1579.7 1490.9 1467.5 1399.9 1291.6 1239.9 1180.9 1128.6 1028.8 1016.9 989.5 948.6 944.2 925.6 916.4 o""c ~OJU.J 789.6 725.6 593.5 582.7 N-H N-H N-H B-H B-H B-H 555.7 370.8 356.6 3669.3 3669.3 3666.2 2676.2 2667.2 2667.2 1495.1 1495.1 1402.3 1402.3 1315.9 1255.1 1087.3 1087.3 1052.1 951.6 951.6 949.2 931.3 930.9 930.9 859.3 734.6 711.7 711.7 517.8 517.8 395.0 282.1 282.1 0.9443 0.9443 0.9443 0.9478 0.9478 0.9478 3465.0 3465.0 3462.0 2536.4 2527.9 2527.9 3456 2806 2517 2393 2222 2142 1998 1917 1863 1457 327 Table 4. Total CCSD(T) electronic energies (in a. u.) as a function of basis set extrapolated to the complete basis set limit. Molecule aVDZ aVTZ aVQZ CBS(DTQ) BNC4H6 -235.041382 -235.248760 -242.025660 -242.242606 -235.306936 -242.304885 -235.339076 -242.339469 Table 5. Components for the atomization. Energies in kcal/mol. Molecule AEcBS AEDKH-SR AEcv AEso AEzPE l:Do TC 1285.3 1218.7 6.3 5.9 -0.99 -1.03 -0.37 60.8 -0.09 58.1 1229.4 3.53 1165.5 3.88 328 Structure Table 6. Heats of fonnation in kcal/mol. Entropies in cal/mol-K. Molecule AHhOK AHh298K So BNC4H6 7.9 3.0 70.10 B3N3H6 -112.8 -119.0 68.73 Table 7. B3LYP/DGDZVP2 binding energies at 0 K in kcal/mol for R-Cr(CO)] complexes. Cr(CO)3 Binding energy C6H6-Cr(CO)3 BNC4H6-Cr(CO)3 B3N3fI6-Cr(CO)3 -54.9 -54.4 -42.7 Table 8. High accuracy (High acc.) and G3MP2 reaction enthalpies at 298 K in kcal/mol. High Reaction Entry G3MP2 acc.a Hrelimination c-C6H12 ~ c-C6H6 + 3 Hz (1) 44.5 0 c-BNC4H12 ~ c-BNC4H6 + 3 Hz (2) 23.5 c-B]N]H12~ c-B]N]H6 + 3 Hz (3) -22.3 -18.9 3 CZH6~ 3 CZH4 + 3 Hz (4) 92.5 100.0b 2 CZH6 + BH]NH] ~ 2 CZH4 + BHzNHz + 3 Hz (5) 54.4 61.5b 3 BH]NH] ~ 3 BHzNHz + 3 Hz (6) -21.9 -15.3 c-C6HIO ~ c-C6Hs + Hz (7) 26.5 c-C6Hs~ c-C6H6 + Hz (8) -5.7 c-C4BNHIO (B=N bond) ~ c-C4BNHs (B=N, C=C(B)) + Hz (9) 25.7 c-C4BNHs (B=N, C=C(B)) ~ c-C4BNH6 + Hz (10) 4.7 c-C4BNHJO (B=N bond) ~ c-C4BNHs (B=N, C=C(N)) + Hz (11) 24.4 c-C4BNHs (B=N, C=C(N)) ~ c-C4BNH6 + Hz (12) 6.1 c-B]N]HIO ~ c-B]N]Hs + Hz (13) -2.1 329 c-B3N3Hs -+ c-B3N3H6 + Hz (14) -27.9 Exchange c-C6H6 + BHzNHz -+ c-C4BNH6 + CZH4 (15) 14.7 14.8 c-C6H6 + 2 c-C 1zH 12 -+ 3 c-C6H IO (16) 35.7 35.7 c-C6H6 + c-C12H12 -+ 3 c-C6HIO + c-C6Hs (17) 34.1 34.0 c-C6H6 + c-C4BNHs (B=N, C=C(B)) -+ c-C4BNH6 + c-C6Hs (18) 12.1 c-C6H6 + c-C4BNHs (B=N, C=C(B)) -+ c-C4BNH6 + c-C~s (19) 13.4 c-B3N3H6 + 2 c-B3N3H1Z -+ 3 c-B3N3H1O (20) 52.8 c-B3N3H6 + c-B3N3H 1Z -+ c-B3N3H IO + c-B3N3Hs (21) 39.3 Decomposition c-C6H6 -+ 3 HC=CH (22) 144.2 143.6 c-BNC4H6 -+ HB=NH + 2 HC=CH (23) 118.0 118.1 c-B3N3H6 ---+ 3 HB=NH (24) 151.9 154.1 a From Hz and CxHy experimental values (NIST Tables) and B compounds CCSD(T)/CBS + corrections values. 330 Table 9. B3LYP/DGDZVP2 and MP2/cc-pVTZ geometrical parameters for C6H6, C4BNH6, and B3N3H6 cycles (bond lengths in angstroms and angles in degrees, see Figure B1 for labeling). Structure Bond or angle B3LYPIDZVP2 MP2/cc-pVTZ C6H6 C-C 1.4018 1.3937 C-H 1.0863 1.0814 L(C-C-C) 120.0 120.0 L(C-C-H) 120.0 120.0 BNC4H 6 BI-N2 1.4419 1.4341 N2-C3 1.3708 1.3629 C3-C4 1.3734 1.3683 C4-C5 1.4304 1.4156 C5-C6 1.3825 1.3787 C6-Bl 1.5177 1.5115 BI-H7 1.1920 1.1904 N2-H8 1.0121 1.0086 C3-H9 1.0855 1.0805 C4-HI0 1.0843 1.0792 C5-Hll 1.0895 1.0843 C6-H12 1.0878 1.0826 L(BI-N2-C3) 123.7 124.1 L(N2-C3-C4) 120.7 120.4 L(C3-C4-C5) 120.1 120.4 L(C4-C5-C6) 121.7 121.6 L(BI-N2-H8) 120.6 120.5 L(N2-C3-H9) 117.4 117.3 L(C3-C4-HlO) 119.3 118.8 L(C4-C5-Hll) 117 " 1177~ ~ I.~ .1. .1. I • I L(C5-C6-HI2) 118.1 117.6 L(C6-BI-H7) 127.1 127.7 B3N3H6 B-N 1.4357 1.4307 B-H 1.1937 1.1910 N-H 1.0104 1.0059 L(B-N-B) 123.0 123.1 L(N-B-N) 117.0 116.9 L(B-N-H) 118.5 118.5 L(N-B-H) 121.5 121.5 331 Table 10. B3LYPIDGDZVP2 geometrical parameters for C6H6-Cr(CO)3, C4BNH6-Cr(COh and B3N3H6- Cr(CO)3 cycles (bond lengths in angstroms and angles in degrees, see Figure B2 for labeling). C6H 6- Bond or angle BNC4H6- Bond or angle B3N3H 6- Bond or angle Cr(CO)3 Cr(COh Cr(CO)3 Cr-CI 1.8564 Cr-CI 1.8646 Cr-CI 1.8495 Cr-C2 1.8564 Cr-C2 1.8508 Cr-C2 1.8495 Cr-C3 1.8564 Cr-C3 1.8547 Cr-C3 1.8494 Cr-C4 2.2438 Cr-B4 2.3676 Cr-B4 2.3387 Cr-C5 2.2438 Cr-N5 2.2274 Cr-N5 2.2674 Cr-C6 2.2444 Cr-C6 2.1691 Cr-B6 2.3384 Cr-C7 2.2443 Cr-C7 2.2341 Cr-N7 2.2664 Cr-C8 2.2443 Cr-C8 2.2508 Cr-B8 2.3371 Cr-C9 2.2444 Cr-C9 2.3008 Cr-N9 2.2674 CI-OlO 1.1688 CI-OIO 1.1664 CI-OlO 1.1697 C2-011 1.1688 C2-011 1.1689 C2-011 1.1696 C3-012 1.1688 C3-012 1.1696 C3-012 1.1696 C4-C5 1.4089 B4-N5 1.4633 B4-N5 1.4515 C5-C6 1.4273 N5-C6 1.3952 N5-B6 1.4516 C6-C7 1.4087 C6-C7 1.4004 B6-N7 1.4514 C7-C8 1.4275 C7-C8 1.4305 N7-B8 1.4515 C8-C9 1.4087 C8-C9 1.4061 B8-N9 1.4516 C9-C4 1.4273 C9-B4 1.5186 N9-B4 1.4517 332 L(CI-Cr-C2) 89.0 L(CJ -Cr-C2) 90.1 L(C I-Cr-C2) 89.2 L(C2-Cr-C3) 89.0 L(C2-Cr-C3) 88.1 L(C2-Cr-C3) 89.4 L(C3-Cr-C I) 89.0 L(C3-Cr-C I) 89.0 L(C3-Cr-C I) 89.1 L(C l-C2-C3-Cr) 55.5 L(C I-C2-C3-Cr) 54.9 L(C I-C2-C3-Cr) 55.4 H H H H B B3 N3 6 Figure 1. C6H6 , C4BNH6, and B)N)H6 cycles with labels. • 333 •c •c• 334 (A) (B) (C) Figure 3. Electrostatic potential maps at the 0.002 electron/a.u.) density iso-contour level (A) c- CoHo (-18.9 to 19.2 kcal.mol), (B) c-BNC4Ho (-13.6 to 39.9 kcal/mol), and (C) c-B1N,Hr. (-20.9 to 54.5 kcaJlmol). Blue is positivc potential (repulsive for the positive charge), red is negative potential (attractive for the positive charge) and green represents near zero potential. 335 HID Exchange: N-H Exchange. A CD30D solution containing hexamethylbenzene as internal standard (1 mL; I mM hexamethylbenzene) was added to a neat sample of 1,2-dihydro-1 ,2-azaborine 1 (0.0060 g, 0.070 mmol) under N2. IH NMR indicated a slow exchange of the N-H resonance at 9.8 ppm (integrated versus the 1,2- dihydro-1 ,2-azaborine C(5)-H resonance at 6.3 ppm). Integration of the 1,2-dihydro-1 ,2- azaborine C(5)-H resonance versus hexamethylbenzene indicated that no appreciable degradation of 1 took place within the timeframe of the HID exchange experiment (30 h). We assumed pseudo first-order kinetics and obtained an exchange rate constant kilO = 7 ± 2 X 10-7 M-'s· 1 (Figure 4). HID Exchange y = 0.0659 475e· Q OOQO'M • R' =0_99750956 0.07 0.06 005 ~ 0.04 --::t ~ 0.03 002 001 0 0 20000 40000 60000 80000 100000 120000 Time (5) Figure 4. Plot of[N-H] (M) versus time (s). From exponential fit, kobs = 1.8 X 10-5 S-I and kHD = 7.5 X 10-7 M-1s- 1 was obtained, where [CD)OD] = 24.6 M. C(3)-H Exchange. The sample from the N-H exchange experiment was charged with CD3COOD (4.0 IJ.L, 0.070 mmol) and CF3COOD (16.3 IJ.L, 0.211 mmol). At t = 24 336 h, IH NMR indicated no deuterium exchange at the C(3}-H position of 1. Minor degradation to unidentified products was noted in the IH and liB NMR spectra. Reactivity with Benzaldehyde: 1,2-Dihydro-l,2-azaborine (1). A J. Young NMR tube was charged with a 0.67 M solution of 1,2-dihydro-1,2-azaborine 1 in CD2Ch (0.40 mL; 0.27 mmoll) and hexamethylbenzene (0.0029 g, 0.018 mmol, internal standard). Benzaldehyde (0.0256 g, 0.241 mmol) was added, the tube was sealed, and the reaction monitored by IH NMR. IH NMR showed no evidence of aldehyde reduction after 16 h at rt. Then, the mixture was heated to 60°C for 60 h and then allowed to cool to rt. IH NMR again showed no evidence ofaldehyde reduction. IH NMR integration of hexamethylbenzene versus 1,2-dihydro-I,2-azaborine indicated little to no degradation of 1. Borazine. A J. Young NMR tube was charged with benzaldehyde (0.050 g, 0.47 mmol), CD2Ch (1.0 mL), and borazine (0.038 g, 0.47 mmol). The tube was sealed and heated at 60°C for 24 h. lH NMR indicated complete consumption of benzaldehyde. Upon workup, reduced benzaldehyde derivatives such as N-benzylidenebenzylamine and N-tribenzylamine were isolated. 337 Crystallographic Data for Complex 12 (liu19) C(6) (71 1) . - .,..,..~ , ........ \ Eq/ \.--- --- .\ \ ... ~p, ~-...- ClSJ '\ ~ C( ),\: 1 / / N(l) -I' . ~ " 1/ ~ " \, 1/ ( \ /,- - Cdl) ~\....J. CIS) /C(91CI1;~ C( l( 0(1) Ol31b ( ~C(2) 0(2) Figure 5. ORTEP illustration of 12, with ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of 12 suitable for X-ray diffraction were obtained by evaporation of a solution of 12 in Et20. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and 338 refined by full matrix least-squares procedures on FZ• All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.1 0) program package (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for Cl3HzoBN03SiCr are given in the following tables. Table 11. Crystal data and structure refinement for 12. a= 104.0960(10)°. 13= 95.5740(10)°. y = 108.4140(10)°. Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size Theta range for data colI. Index ranges Reflections collected Independent reflections Completeness to 8 = 27.00° Absorption correction liu19 Cl3 Hzo B CrN 0 3 Si 329.20 173(2) K 0.71073 A Triclinic P-1 a = 6.9391(5) A b = 10.2736(7) A c = 12.4331(8) A 800.92(9) A3 2 1.365 Mg/m3 0.793 mm- l 344 0.27 x 0.17 x 0.12 mm3 1.72 to 27.00°. -8<=h<=8, -13<=k<=13, -15<=1<=15 8584 3450 [R(int) = 0.0209] 98.9% Semi-empirical from equivalents Max. and min. transmission 0.9108 and 0.8144 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 3450/0/261 Goodness-of-fit on F2 1.076 Final R indices [1>20(1)] R1 = 0.0354, wR2 = 0.0863 R indices (all data) R1 = 0.0432, wR2 = 0.0925 Largest diff. peak and hole 0.458 and -0.225 e.A-3 Table 12. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2x 103) for liul9. U(eq) is defmed as one third of the trace of the orthogonalized Uij tensor. x y z U(eg) Cr(l) 9948(1) 9749(1) 2072(1) 23(1) Si(l) 7156(1) 6555(1) 2816(1) 24(1) 0(1) 6254(2) 9003(2) 266(1) 37(1) 0(2) 11612(3) 12588(2) 1621(2) 46(1) 0(3) 7969(3) 11203(2) 3785(2) 43(1) N(I) 9429(3) 7702(2) 2451(1) 25(1) B(I) 9727(4) 7441(3) 1286(2) 29(1) C(I) 7662(3) 9275(2) 956(2) 27(1) C(2) 10999(3) 11490(2) 1793(2) 32(1) C(3) 8714(3) 10618(2) 3117(2) 29(1) C(4) 10958(4) 8803(2) 3312(2) 30(1) C(5) 12746(3) 9697(3) 3062(2) 31(1) C(6) 13021(3) 9547(3) 1936(2) 30(1) C(7) 11584(4) 8450(3) 1057(2) 30(1) C(8) 4884(4) 6122(3) 1709(3) 37(1) C(9) 6758(5) 7573(3) 4182(2) 39(1) C(lO) 7752(3) 4927(2) 2951(2) 29(1) C(11) 7403(5) 3851(3) 1790(2) 42(1) C(l2) 6282(4) 4202(3) 3652(2) 40(1) C(l3) 9995(4) 5357(3) 3558(2) 38(1) Table 13. Bond lengths [A] and angles [0] for liul9. 339 Cr(l)-C(3) Cr(l)-C(2) Cr(I)-C(I) Cr(l)-C(4) Cr(l)-N(I) Cr(I)-C(5) Cr(I)-C(6) Cr(I)-C(7) Cr(1)-B(1) Si(l)-N(I) Si(I)-C(8) Si(l)-C(9) SiC1)-C(l0) O(l)-C(l) 1.831(2) 1.838(2) 1.854(2) 2.182(2) 2.1927(18) 2.218(2) 2.225(2) 2.253(2) 2.283(3) 1.8188(19) 1.848(3) 1.861(3) 1.886(2) 1.147(3) O(2)-C(2) 1.154(3) O(3)-C(3) 1.164(3) N(1 )-C(4) 1.408(3) N(1)-B(1) 1.455(3) B(l )-C(7) 1.479(4) B(1)-H(1B) 1.02(2) C(4)-C(5) 1.406(3) C(4)-H(4) 1.03(2) C(5)-C(6) 1.409(3) C(5)-H(5) 0.91(3) C(6)-C(7) 1.391(3) C(6)-H(6) 0.92(2) C(7)-H(7) 0.90(2) C(8)-H(8A) 0.93(3) C(8)-H(8B) 0.90(3) C(8)-H(8C) 0.87(3) C(9)-H(9A) 0.98(3) C(9)-H(9B) 0.90(3) C(9)-H(9C) 0.93(3) C(10)-C(11) 1.533(3) C(10)-C(13) 1.537(3) C(l0)-C(l2) 1.537(3) C(lI)-H(lIA) 0.97(3) C(lI)-H(11B) 0.98(3) C(lI)-H(11C) 0.91(3) C(l2)-H(12A) 0.98(3) C(l2)-H(12B) 0.97(3) C(12)-H(12C) 0.94(3) C(l3)-H(13A) 1.02(3) C(13)-H(13B) 0.96(3) C(l3)-H(13C) 0.95(3) C(3)-Cr(1 )-C(2) 86.78(10) C(3)-Cr(1)-C(I) 90.36(9) C(2)-Cr(1)-C(1) 88.78(10) C(3)-Cr(1)-C(4) 88.78(9) C(2)-Cr(1)-C(4) 133.77(10) C(1)-Cr(1)-C(4) 137.27(9) C(3)-Cr(1)-N(1) 101.17(8) C(2)-Cr(1)-N(1) 166.99(9) C(l)-Cr(1)-N(1) 101.33(8) C(4)-Cr(l)-N(1) 37.55(8) C(3)-Cr(l )-C(5) 105.25(9) C(2)-Cr(1)-C(5) 100.66(10) C(l)-Cr(1)-C(5) 162.06(9) C(4)-Cr(1)-C(5) 37.25(9) N(l)-Cr(1)-C(5) 67.46(8) C(3)-Cr(1)-C(6) 138.91(9) C(2)-Cr(l)-C(6) 86.83(9) C(l)-Cr(1)-C(6) 130.00(9) C(4)-Cr(1)-C(6) 67.44(9) N(l)-Cr(1)-C(6) 80.41(8) C(5)-Cr(1)-C(6) 36.99(8) C(3)-Cr(1)-C(7) 168.06(9) 340 C(2)-Cr(1 )-C(7) 102.40(9) C(1)-Cr(I)-C(7) 97.37(9) C(4)-Cr(1)-C(7) 79.36(9) N(1)-Cr(1)-C(7) 68.45(8) C(5)-Cr(1)-C(7) 65.84(9) C(6)-Cr(1)-C(7) 36.20(9) C(3)-Cr(1)-B(1) 134.96(10) C(2)-Cr(1)-B(1) 137.42(10) C(1)-Cr(1)-B(1) 83.85(9) C(4)-Cr(1)-B(1) 67.39(9) N(I)-Cr(l)-B(1) 37.87(8) C(5)-Cr(1)-B(1) 78.87(9) C(6)-Cr(1)-B(I) 67.19(9) C(7)-Cr(1)-B(1) 38.04(9) N(l )-Si(1 )-C(8) 108.92(11) N(I)-Si(I)-C(9) 107.86(11) C(8)-Si(1)-C(9) 109.17(14) N(1)-Si(1)-C(lO) 106.18(9) C(8)-Si(1)-C(1 0) 113.20(12) C(9)-Si(1)-C(10) 111.31(12) C(4)-N(1)-B(1) 119.94(19) C(4)-N(1)-Si(1) 119.50(15) B(1)-N(1)-Si(1) 120.47(16) C(4)-N(1)-Cr(1) 70.83(12) B(1)-N(1)-Cr(1) 74.45(13) Si(1)-N(1)-Cr(1) 129.45(9) N(1)-B(l)-C(7) 117.0(2) N(l)-B(1)-Cr(1) 67.68(12) C(7)-B(1)-Cr(1) 69.86(14) N(1)-B(1)-H(1B) 118.3(14) C(7)-B(1)-H(lB) 124.7(14) Cr(1)-B(1)-H(lB) 133.6(14) O(1)-C(1)-Cr(1) 179.01 (19) O(2)-C(2)-Cr(1) 178.3(2) O(3)-C(3)-Cr(1) 178.3(2) C(5)-C(4)-N(1) 121.0(2) C(5)-C(4)-Cr(1) 72.76(13) N(1)-C(4)-Cr(1) 71.63(12) C(5)-C(4)-H(4) 120.7(13) N(1)-C(4)-H(4) 118.3(13) Cr(1)-C(4)-H(4) 128.8(13) C(4)-C(5)-C(6) 120.7(2) C(4)-C(5)-Cr(l) 69.99(13) C(6)-C(5)-Cr(1) 71.77(13) C(4)-C(5)-H(5) 118.3(16) C(6)-C(5)-H(5) 120.6(16) Cr(1 )-C(5)-H(5) 125.2(16) C(7)-C(6)-C(5) 120.4(2) C(7)-C(6)-Cr(1) 72.99(13) C(5)-C(6)-Cr(1) 71.24(13) C(7)-C(6)-H(6) 120.6(14) C(5)-C(6)-H(6) 118.9(15) Cr(1)-C(6)-H(6) 124.9(15) 341 C(6)-C(7)-B(1) 120.7(2) C(6)-C(7)-Cr(1) 70.81(13) B(1 )-C(7)-Cr(1) 72.1 0(13) C(6)-C(7)-H(7) 119.1(16) B(1)-C(7)-H(7) 120.1(16) Cr(1)-C(7)-H(7) 126.3(15) Si(1)-C(8)-H(8A) 109.2(19) Si(1)-C(8)-H(8B) 110(2) H(8A)-C(8)-H(8B) 110(3) Si(1)-C(8)-H(8C) 114(2) H(8A)-C(8)-H(8C) 111(3) H(8B)-C(8)-H(8C) 103(3) Si(1)-C(9)-H(9A) 113.4(19) Si(1)-C(9)-H(9B) 112(2) H(9A)-C(9)-H(9B) 112(3) Si(1 )-C(9)-H(9C) 106.2(18) H(9A)-C(9)-H(9C) 108(3) H(9B)-C(9)-H(9C) 105(3) C(11)-C(10)-C(13) 109.4(2) C(11)-C(10)-C(12) 108.6(2) C(13)-C(10)-C(12) 108.9(2) C(11)-C(10)-Si(1) 111.12(17) C(13)-C(10)-Si(1) 110.79(16) C(12)-C(10)-Si(1) 107.98(16) C(10)-C(11)-H(11A) 110.9(18) C(10)-C(11)-H(11B) 109.5(16) H(11A)-C(11)-H(1lB) 109(2) C(10)-C(11)-H(11C) llO.0(17) H(11A)-C(11)-H(11C) 109(2) H(11B)-C(11)-H(11C) 108(2) C(10)-C(12)-H(12A) 110.7(18) C(1O)-C(12)-H(12B) 110.9(17) H(12A)-C(12)-H(12B) 106(2) C(10)-C(12)-H(12C) ll1.2(17) H(12A)-C(12)-H(12C) 110(2) H(12B)-C(12)-H(12C) 108(2) C(10)-C(13)-H(13A) 110.6(17) C(10)-C(13)-H(13B) 111.0(17) H(13A)-C(13)-H(13B) 107(2) C(10)-C(13)-H(13C) 112.3(17) H(13A)-C(13)-H(13C) 109(2) H(13B)-C(13)-H(13C) 107(2) Symmetry transformations used to generate equivalent atoms: Table 14. Anisotropic displacement parameters (A2x 103)for liu19. The anisotropic displacement factor exponent takes the form: -2:n:2[ h2a*2U lI + ... + 2 h k a* b* Ul2 ] UII U22 U33 U23 Ul3 Ul2 Cr(1) 20(1) 24(1) 24(1) 6(1) 5(1) 8(1) Si(1) 24(1) 23(1) 26(1) 6(1) 6(1) 8(1) 0(1) 28(1) 47(1) 33(1) 13(1) 2(1) 11(1) 0(2) 37(1) 28(1) 73(1) 19(1) 12(1) 7(1) 342 343 0(3) 48(1) 45(1) 41(1) 6(1) 16(1) 26(1) N(1) 25(1) 27(1) 24(1) 8(1) 6(1) 10(1) B(1) 30(1) 37(1) 27(1) 13(1) 9(1) 16(1) C(1) 27(1) 28(1) 29(1) 10(1) 11(1) 9(1) C(2) 23(1) 30(1) 41(1) 8(1) 7(1) 8(1) C(3) 28(1) 29(1) 30(1) 8(1) 4(1) 11(1) C(4) 30(1) 35(1) 31(1) 13(1) 6(1) 14(1) C(5) 23(1) 40(1) 32(1) 10(1) 4(1) 13(1) C(6) 22(1) 36(1) 40(1) 17(1) 11(1) 13(1) C(7) 33(1) 36(1) 30(1) 14(1) 15(1) 20(1) C(8) 28(1) 37(1) 46(2) 16(1) 3(1) 12(1) C(9) 48(2) 33(1) 39(1) 9(1) 24(1) 13(1) C(10) 32(1) 27(1) 30(1) 10(1) 5(1) 12(1) C(11) 55(2) 33(1) 41(2) 6(1) 7(1) 23(1) C(12) 40(2) 35(1) 49(2) 22(1) 11(1) 13(1) C(13) 33(1) 44(2) 43(2) 20(1) 4(1) 17(1) Table 15. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2x 103) for liu19. x y z U(eq) H(1B) 8650(40) 6590(30) 690(20) 35(7) H(4) 10740(30) 8930(20) 4131(19) 26(6) H(5) 13650(40) 10440(30) 3640(20) 33(7) H(6) 14120(40) 10220(30) 1789(19) 26(6) H(7) 11750(40) 8400(30) 340(20) 29(6) H(8A) 3760(50) 5430(30) 1840(30) 58(9) H(8B) 4590(50) 6920(40) 1720(30) 60(9) H(8C) 5090(50) 5840(30) 1020(30) 58(10) H(9A) 7770(50) 7680(30) 4830(30) 66(10) H(9B) 6670(50) 8420(40) 4160(30) 63(10) H(9C) 5450(50) 7050(30) 4280(20) 57(9) H(11A) 5990(50) 3560(30) 1390(30) 57(9) H(11B) 7680(40) 3000(30) 1880(20) 53(8) H(11C) 8300(40) 4250(30) 1370(20) 39(8) H(12A) 6480(50) 3310(30) 3700(20) 55(9) H(12B) 6570(40) 4810(30) 4420(20) 42(7) H(12C) 4900(50) 4010(30) 3340(20) 47(8) H(13A) 10270(50) 4490(30) 3700(20) 53(8) H(13B) 10260(40) 6050(30) 4280(20) 46(8) H(13C) 10970(40) 5770(30) 3140(20) 45(8) 344 O)'stal/ograp!lic Data fol' /3 (/iff22) • Dill Figure 6. ORTEP illustration of 13, with ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of 13 suitable for X-ray diffraction were obtained by evaporation of a solution of 13 in Et20. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was 345 solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2• All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for C7H6BCrN03 are given in the following tables. Table 16. Crystal data and structure refmement for 13. u= 90°. Monoclinic ~= 115.9460(10)°. y = 90°. Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size Theta range for data colI. Index ranges Reflections collected Independent reflections Hu22 C7 H6 B CrN 03 214.94 173(2) K 0.71073 A P2(1)/c a = 11.5311(8) A b = 6.9443(5) A c = 12.2196(8) A 879.86(11) A3 4 1.623 Mg/m3 1.267 mm- I 432 0.20 x 0.14 x 0.09 mm3 1.96 to 26.99°. -14<=h<=14, -8<=k<=8, -15<=1<=15 9413 1915 [R(int) = 0.0262] Completeness to 8 = 26.99° 100.0 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.8945 and 0.7856 Refinement method Pull-matrix least-squares on p2 Data / restraints / parameters 1915 / 0 / 142 Goodness-of-fit on p2 1.027 Pinal R indices [1>20(1)] R1 = 0.0293, wR2 = 0.0728 R indices (all data) Rl = 0.0345, wR2 = 0.0765 Largest diff. peak and hole 0.439 and -0.201 e.A3 Table 17. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2X 103) for Hu22. V(eq) is defined as one third of the trace of the orthogonaHzed Vij tensor. x y z V(eq) Cr(1) 2370(1) 9733(1) 2264(1) 21(1) 0(1) 1041(2) 12842(2) 445(2) 44(1) 0(2) 3615(2) 12715(3) 4195(2) 53(1) 0(3) 186(2) 9828(3) 2967(2) 52(1) N(1) 1888(2) 7035(3) 1254(2) 32(1) B(1) 2437(3) 8204(4) 622(2) 36(1) C(1) 1550(2) 11645(3) 1144(2) 30(1) C(2) 3144(2) 11566(3)3442(2) 34(1) C(3) 1022(2) 9763(3) 2693(2) 33(1) C(4) 2508(2) 6636(3) 2480(2) 29(1) C(5) 3719(2) 7363(3) 3174(2) 29(1) C(6) 4323(2) 8609(3) 2657(2) 35(1) C(7) 3717(2) 9059(3) 1422(2) 35(1) Table 18. Bond lengths [A] and angles [0] for Hu22. 346 Cr(1)-C(2) Cr(1)-C(1) Cr(1)-C(3) Cr(1)-C(4) Cr(1)-N(1) Cr(1)-C(5) Cr(I)-C(6) Cr(I)-C(7) Cr(1)-B(1) 0(1)-C(1) 0(2)-C(2) 0(3)-C(3) N(1)-C(4) N(1)-B(1) N(1)-H(1N) B(1)-C(7) B(1)-H(1B) 1.834(2) 1.843(2) 1.845(2) 2.164(2) 2.1781(18) 2.203(2) 2.228(2) 2.256(2) 2.301(2) 1.152(3) 1.158(3) 1.152(3) 1.377(3) 1.443(3) 0.80(3) 1.492(4) 1.03(2) C(4)-C(5) 1.374(3) C(4)-H(4) 0.88(3) C(5)-C(6) 1.421(3) C(5)-H(5) 0.80(2) C(6)-C(7) 1.393(3) C(6)-H(6) 0.90(3) C(7)-H(7) 0.90(3) C(2)-Cr(1)-C(1) 89.93(9) C(2)-Cr(1)-C(3) 87.17(10) C(1)-Cr(1)-C(3) 88.86(9) C(2)-Cr(1)-C(4) 127.54(9) C(1)-Cr(1)-C(4) 142.42(9) C(3)-Cr(1)-C(4) 90.16(9) C(2)-Cr(1)-N(1) 163.27(9) C(1)-Cr(1)-N(1) 106.12(8) C(3)-Cr(1)-N(1) 97.62(9) C(4)-Cr(1)-N(1) 36.97(7) C(2)-Cr(1)-C(5) 97.39(9) C(1)-Cr(1)-C(5) 158.88(9) C(3)-Cr(1)-C(5) 111.19(9) C(4)-Cr(1)-C(5) 36.66(8) N(1)-Cr(1)-C(5) 65.93(8) C(2)-Cr(1)-C(6) 88.58(9) C(1)-Cr(1)-C(6) 123.67(9) C(3)-Cr(1)-C(6) 147.19(9) C(4)-Cr(1)-C(6) 67.17(8) N(1)-Cr(1)-C(6) 78.69(8) C(5)-Cr(1)-C(6) 37.42(8) C(2)-Cr(1)-C(7) 107.83(9) C(1)-Cr(1)-C(7) 92.47(9) C(3)-Cr(1)-C(7) 164.93(9) C(4)-Cr(1)-C(7) 79.67(8) N(1)-Cr(1)-C(7) 67.60(8) C(5)-Cr(1)-C(7) 66.44(8) C(6)-Cr(1)-C(7) 36.18(9) C(2)-Cr(1)-B(1) 144.52(10) C(1)-Cr(1)-B(1) 83.51(9) C(3)-Cr(1)-B(1) 127.32(10) C(4)-Cr(1)-B(1) 67.58(9) N(1)-Cr(1)-B(1) 37.45(8) C(5)-Cr(1)-B(1) 79.04(9) C(6)-Cr(1)-B(1 ) 67.04(1 0) C(7)-Cr(1)-B(1) 38.21(9) C(4)-N(1)-B(1) 123.7(2) C(4)-N(1)-Cr(1) 70.97(11) B(1)-N(1)-Cr(1) 75.92(12) C(4)-N(1)-H(1N) 116.9(19) B(l)-N(1)-H(1N) 119.4(19) Cr(1)-N(1)-H(1N) 124.4(19) N(I)-B(1)-C(7) 114.4(2) N(I)-B(1)-Cr(1) 66.64(11) C(7)-B(1)-Cr(1) 69.25(12) N(1)-B(1)-H(1B) 117.4(13) 347 C(7)-B(1)-H(lB) 128.1(13) Cr(1)-B(1)-H(lB) 129.7(14) O(1)-C(1)-Cr(1) 179.7(2) 0(2)-C(2)-Cr(1) 178.6(2) 0(3)-C(3)-Cr(l) 178.4(2) C(5)-C(4)-N(1) 120.1(2) C(5)-C(4)-Cr(1) 73.20(13) N(1)-C(4)-Cr(1) 72.07(11) C(5)-C(4)-H(4) 120.2(17) N(1)-C(4)-H(4) 119.6(17) Cr(1)-C(4)-H(4) 124.7(17) C(4)-C(5)-C(6) 120.8(2) C(4)-C(5)-Cr(1) 70.14(12) C(6)-C(5)-Cr(1) 72.25(12) C(4)-C(5)-H(5) 118.0(17) C(6)-C(5)-H(5) 120.7(17) Cr(1)-C(5)-H(5) 123.0(17) C(7)-C(6)-C(5) 120.5(2) C(7)-C(6)-Cr(1) 73.01(13) C(5)-C(6)-Cr(1) 70.34(12) C(7)-C(6)-H(6) 122.7(17) C(5)-C(6)-H(6) 116.5(17) Cr(1)-C(6)-H(6) 124.2(17) C(6)-C(7)-B(1) 120.2(2) C(6)-C(7)-Cr(1) 70.81(12) B(1 )-C(7)-Cr(1) 72.54(12) C(6)-C(7)-H(7) 116.1(19) B(1 )-C(7)-H(7) 123.4(19) Cr(1)-C(7)-H(7) 124.2(18) Symmetry transformations used to generate equivalent atoms: Table 19. Anisotropic displacement parameters (Nx 103)for liu22. The anisotropic displacement factor exponent takes the form: -2:n2[ h2a*2Ull + ... + 2 h k a* b* Ul2 ] Ull U22 U33 U23 UB Ul2 Cr(1) 20(1) 20(1) 21(1) 0(1) 8(1) 0(1) 0(1) 48(1) 34(1) 37(1) 10(1) 7(1) 5(1) 0(2) 59(1) 44(1) 38(1) -17(1) 5(1) 1(1) 0(3) 44(1) 61(1) 64(1) 10(1) 37(1) 14(1) N(1) 30(1) 25(1) 37(1) -7(1) 12(1) -5(1) B(1) 51(2) 34(1) 29(1) -5(1) 22(1) 3(1) C(1) 31(1) 26(1) 27(1) -4(1) 8(1) -3(1) C(2) 33(1) 33(1) 28(1) 1(1) 8(1) 6(1) C(3) 34(1) 31(1) 35(1) 5(1) 16(1) 7(1) C(4) 30(1) 22(1) 41(1) 5(1) 19(1) 3(1) C(5) 26(1) 30(1) 31(1) 7(1) 12(1) 9(1) C(6) Tun 34(1) 50(1) ~4(1) 18(1) -1(1)~~\'J C(7) 42(1) 32(1) 45(1) 0(1) 32(1) -1(1) Table B20. Hydrogen coordinates (x 104) and isotropic displacement parameters (Nx 103) for Hu22. 348 349 x y z U(eq) H(lN) 1170(30) 6630(40) 890(20) 43(8) H(lB) 1880(20) 8430(30) -300(20) 43(7) H(4) 2110(20) 5950(40) 2820(20) 41(7) H(5) 4030(20) 7190(30) 3890(20) 35(7) H(6) 5070(30) 9170(40) 3180(20) 45(7) H(7) 4110(30) 9960(40) 1170(30) 51(8) B.2.3. Supplemental information for Chapter III, section 3.4 Table 21. Azaborine line list of measured frequencies (obs) for the normal isotopomer, H6Bll_NI4C4' The frequencies are given in MHz. The column (o-c) lists the deviations of the "best fit" calculated frequencies ( c ) from the measured freguencies (0). J" K a" Ke" Fl" F" J' K a' Ke' Fl' F' obs o-c 1 0 1 2 2 0 0 0 2 2 8097.956 -0.004 1 0 1 2 2 0 0 0 2 3 8097.956 -0.004 1 0 1 2 3 0 0 0 2 2 8098.072 -0.005 1 0 1 2 3 0 0 0 2 3 8098.072 -0.005 1 0 1 2 1 0 0 0 2 1 8098.168 0.012 1 0 1 2 1 0 0 0 2 2 8098.168 0.012 1 0 1 3 4 0 0 0 2 3 8098.458 -0.013 1 0 1 3 3 0 0 0 2 2 8098.580 0.003 1 0 1 3 3 0 0 0 2 3 8098.580 0.003 1 0 1 1 2 0 0 0 2 1 8098.869 0.000 1 0 1 1 2 0 0 0 2 2 8098.869 0.000 1 0 1 1 2 0 0 0 2 3 8098.869 0.000 1 1 1 2 2 0 0 0 2 1 8405.945 -0.018 1 1 1 2 2 0 0 0 2 2 8405.945 -0.018 1 1 1 2 2 0 0 0 2 3 8405.945 -0.018 1 1 1 2 3 0 0 0 2 2 8406.217 0.013 1 1 1 2 3 0 0 0 2 3 8406.217 0.013 1 1 1 2 1 0 0 0 2 1 8406.346 0.008 1 1 1 2 1 0 0 0 2 2 8406.346 0.008 1 1 1 3 2 0 0 0 2 1 8406.439 0.005 1 1 1 3 2 0 0 0 2 3 8406.439 0.005 1 1 1 3 4 0 0 0 2 3 8406.493 0.003 1 1 1 1 1 0 0 0 2 1 8406.816 0.004 1 1 1 1 1 0 0 0 2 2 8406.816 0.004 1 1 1 1 2 0 0 0 2 1 8406.883 -0.005 1 1 1 1 2 0 0 0 2 2 8406.883 -0.005 1 1 1 1 2 0 0 0 2 3 8406.883 -0.005 2 1 1 3 3 2 1 2 3 2 7801.448 0.002 2 1 1 3 2 2 1 2 3 3 7801.369 0.003 2 1 1 2 2 2 1 2 3 2 7801.141 -0.007 350 2 1 1 2 3 2 1 2 3 3 7801.068 -0.005 2 1 1 4 5 2 1 2 3 4 7801.015 0.003 2 1 1 4 5 2 1 2 3 4 7801.003 -0.009 2 1 1 2 2 2 1 2 3 3 7800.952 -0.008 2 1 1 3 2 2 1 2 2 1 7800.936 -0.003 2 1 1 1 2 2 1 2 3 2 7800.809 -0.008 2 1 1 4 4 2 1 2 3 3 7800.737 0.010 2 1 1 3 3 2 1 2 2 2 7800.658 -0.003 2 1 1 3 4 2 1 2 4 5 7800.617 0.014 2 1 1 3 4 2 1 2 4 3 7800.518 0.011 2 1 1 4 3 2 1 2 2 3 7800.415 -0.003 2 1 1 2 2 2 1 2 2 2 7800.374 0.012 2 1 1 3 4 2 1 2 4 4 7800.246 0.007 2 1 1 4 3 2 1 2 2 2 7800.246 -0.016 2 1 1 1 2 2 1 2 2 3 7800.177 -0.010 2 1 1 1 2 2 1 2 4 3 7799.879 0.013 2 1 1 3 3 2 0 2 3 2 7827.221 -0.003 2 1 1 2 1 2 0 2 3 2 7827.056 0.000 2 1 1 4 3 2 0 2 3 4 7826.695 0.001 2 1 1 3 2 2 0 2 2 3 7826.695 -0.008 2 1 1 3 4 2 0 2 2 3 7826.611 0.005 2 1 1 4 4 2 0 2 3 3 7826.511 0.003 2 1 1 3 3 2 0 2 2 2 7826.437 -0.007 2 1 1 3 4 2 0 2 4 5 7826.381 -0.001 2 1 1 3 4 2 0 2 4 3 7826.301 0.010 2 1 1 2 2 2 0 2 2 1 7826.301 -0.009 2 1 1 4 3 2 0 2 2 3 7826.198 0.002 2 1 1 2 3 2 0 2 4 3 7826.106 0.011 2 1 1 4 3 2 0 2 2 2 7826.026 -0.020 2 1 1 3 3 2 0 2 4 4 7826.026 0.011 2 1 1 4 3 2 0 2 4 3 7825.893 0.011 2 1 1 3 2 2 0 2 1 2 7825.793 -0.017 2 1 1 1 2 2 0 2 2 2 7825.793 -0.021 2 1 1 1 2 2 0 2 4 3 7825.660 0.010 2 1 1 2 2 2 0 2 1 2 7825.403 -0.001 2 1 1 4 3 2 0 2 1 2 7825.294 -0.010 3 2 1 4 3 3 2 2 4 3 7355.761 0.006 3 2 1 4 3 3 2 2 2 2 7355.761 0.006 3 2 1 4 3 3 2 2 3 2 7355.761 0.006 3 2 1 4 3 3 2 2 ~ 3 7355.761 0.006 -' 3 2 1 4 3 3 2 2 4 3 7355.761 0.006 3 2 1 4 5 3 2 2 3 4 7355.629 -0.012 3 2 1 4 5 3 2 2 4 5 7355.629 -0.013 3 2 1 4 5 3 2 2 5 4 7355.629 -0.013 351 3 2 1 4 5 3 2 2 5 6 7355.629 -0.013 3 2 1 4 4 3 2 2 2 3 7355.523 0.005 3 2 1 4 4 3 2 2 3 4 7355.523 0.005 3 2 1 4 4 3 2 2 4 4 7355.523 0.005 3 2 1 4 4 3 2 2 5 4 7355.523 0.005 3 2 1 4 4 3 2 2 5 5 7355.523 0.005 3 2 1 3 2 3 2 2 2 1 7355.492 0.002 3 2 1 3 2 3 2 2 2 2 7355.492 0.002 3 2 1 3 2 3 2 2 3 2 7355.492 0.002 3 2 1 3 2 3 2 2 3 3 7355.492 0.002 3 2 1 2 1 3 2 2 2 1 7355.038 0.016 3 2 1 2 1 3 2 2 2 2 7355.038 0.016 3 2 1 5 6 3 2 2 4 5 7355.141 0.002 3 2 1 5 6 3 2 2 5 5 7355.141 0.002 3 2 1 5 6 3 2 2 5 6 7355.141 0.002 3 2 1 5 4 3 2 2 4 4 7355.084 -0.014 3 2 1 5 4 3 2 2 3 3 7355.084 -0.014 3 2 1 5 4 3 2 2 4 5 7355.084 -0.014 3 2 1 5 4 3 2 2 5 4 7355.084 -0.014 2 1 2 3 3 1 1 1 3 2 13596.162 0.008 2 1 2 3 2 1 1 1 2 2 13596.443 0.006 2 1 2 2 3 1 1 1 3 4 13596.544 0.004 2 1 2 3 3 1 1 1 2 2 13596.632 0.006 2 1 2 2 2 1 1 1 2 3 13596.997 0.014 2 1 2 1 2 1 1 1 1 2 13597.040 0.004 2 1 2 2 1 1 1 1 2 2 13597.040 -0.012 2 1 2 2 3 1 1 1 2 2 13597.067 0.000 2 1 2 1 2 1 1 1 1 1 13597.113 -0.001 2 1 2 4 3 1 1 1 2 3 13597.153 0.005 2 0 2 2 2 1 1 1 3 3 13570.718 -0.004 2 0 2 2 3 1 1 1 3 4 13570.764 0.002 2 0 2 3 3 1 1 1 2 2 13570.848 0.004 2 0 2 2 2 1 1 1 2 3 13571.203 0.004 2 0 2 2 1 1 1 1 2 2 13571.264 -0.011 2 0 2 2 3 1 1 1 2 2 13571.293 0.004 2 0 2 1 1 1 1 1 1 2 13571.325 -0.001 2 0 2 1 2 1 1 1 1 1 13571.325 -0.007 2 0 2 1 1 1 1 1 1 1 13571.401 -0.003 2 0 2 2 2 1 1 1 2 2 13571.434 -0.006 2 0 2 1 2 1 1 1 3 3 13571.475 0.012 2 0 2 3 3 1 0 1 3 3 13878.223 -0.008 2 0 2 3 3 1 0 1 3 4 13878.325 -0.011 2 0 2 3 3 1 0 1 3 2 13878.389 0.010 2 0 2 2 3 1 0 1 1 2 13878.389 0.006 352 2 0 2 3 3 1 0 1 2 3 13878.744 0.013 2 0 2 2 3 1 0 1 3 2 13878.822 -0.001 2 0 2 2 2 1 0 1 3 3 13878.822 -0.004 2 0 2 2 1 1 0 1 2 1 13879.080 -0.002 2 0 2 2 3 1 0 1 2 3 13879.171 -0.004 2 1 2 3 4 1 0 1 3 3 13903.952 -0.007 2 1 2 3 3 1 0 1 3 3 13904.002 -0.010 2 1 2 2 1 1 0 1 1 1 13904.175 -0.001 2 1 2 4 3 1 0 1 1 2 13904.476 -0.006 2 1 2 2 1 1 0 1 3 2 13904.580 -0.007 2 2 1 2 2 2 1 2 1 2 8723.804 -0.002 2 2 1 4 5 2 1 2 4 4 8724.054 0.013 2 2 1 1 1 2 1 2 2 2 8724.108 0.001 2 2 1 2 3 2 1 2 4 4 8724.157 0.003 2 2 1 3 2 2 1 2 1 2 8724.180 -0.009 2 2 1 2 2 2 1 2 4 3 8724.379 -0.001 Table 22. Azaborine line list for lIt,BIO-NI4C4. Frequencies are given in MHz. J' K a' K e' Fl F J" K a" Ke" F I " F" Frequency o-c 1 0 1 3 3 0 0 0 3 2 8133.594 0.0259 1 0 1 3 3 0 0 0 3 3 8133.594 0.0259 1 0 1 3 3 0 0 0 3 4 8133.594 0.0259 1 0 1 3 4 0 0 0 3 4 8133.693 0.0077 1 0 1 3 4 0 0 0 3 3 8133.693 0.0077 1 0 1 4 5 0 0 0 3 4 8134.331 0.0043 1 0 1 4 4 0 0 0 3 3 8134.403 -0.0098 1 0 1 4 4 0 0 0 3 4 8134.403 -0.0098 1 0 1 2 2 0 0 0 3 2 8134.608 -0.0055 1 0 1 2 2 0 0 0 3 3 8134.608 -0.0055 1 1 1 4 5 0 0 0 3 4 8575.871 -0.0216 1 1 1 4 4 0 0 0 3 3 8576.067 -0.0033 1 1 1 4 4 0 0 0 3 4 8576.067 -0.0033 1 1 1 3 4 0 0 0 3 4 8575.561 -0.025 1 1 1 3 4 0 0 0 3 3 8575.561 -0.025 1 1 1 3 2 0 0 0 3 2 8575.678 0.0218 1 1 1 3 2 0 0 0 3 3 8575.678 0.0217 2 0 2 3 4 1 0 1 4 3 14086.77 -0.0034 2 0 2 3 2 1 0 1 4 3 14086.77 -0.0057 2 0 2 2 2 1 0 1 2 3 14086.86 -0.0146 2 0 2 2 2 1 0 1 2 1 14086.96 0.0211 2 0 2 2 1 1 0 1 2 1 14087.2 -0.0168 2 0 2 3 3 1 0 1 3 3 14087.46 0.0104 2 0 2 5 5 1 0 1 4 5 14087.74 0.0047 353 2 0 2 1 1 1 0 1 2 2 14087.86 0.0255 2 0 2 4 5 1 0 1 3 4 14087.15 -0.0018 2 0 2 5 6 1 0 1 4 5 14087.42 0.0167 2 0 2 5 4 1 0 1 4 3 14087.5 0.0072 2 0 2 3 3 1 0 1 3 2 14087.26 -0.0335 2 0 2 4 5 1 0 1 4 5 14086.52 0.0071 2 0 2 3 4 1 0 1 2 3 14086.41 -0.0061 2 0 2 3 3 1 0 1 2 2 14086.36 -0.0402 2 1 2 3 2 1 1 1 2 1 13697.22 0.0209 2 1 2 3 2 1 1 1 3 2 13697.56 -0.0041 2 1 2 4 4 1 1 1 3 3 13697.64 -0.0071 2 1 2 5 4 1 1 1 2 3 13697.71 -0.0177 2 1 2 2 3 1 1 1 2 3 13697.73 -0.0093 2 1 2 2 3 1 1 1 2 2 13697.82 0.0016 2 1 2 2 1 1 1 1 2 2 13697.82 -0.0001 2 1 2 2 1 1 1 1 2 1 13697.92 -0.0071 2 1 2 5 6 1 1 1 4 5 13697.99 -0.0054 2 1 2 5 4 1 1 1 4 3 13698.13 -0.017 2 1 2 2 3 1 1 1 3 2 13698.3 0.0107 2 1 2 2 1 1 1 1 3 2 13698.3 0.0089 2 1 2 1 0 1 1 1 2 1 13698.37 -0.0248 2 1 2 2 3 1 1 1 3 4 13698.37 0.0128 2 1 2 1 1 1 1 1 2 2 13698.47 -0.0058 2 1 2 2 2 1 0 1 2 2 14139.07 0.0203 2 1 2 2 2 1 0 1 2 1 14139.07 -0.0268 2 1 2 3 3 1 0 1 3 2 14139.46 -0.0088 2 1 2 5 5 1 0 1 4 4 14139.84 0.0211 2 1 2 1 0 1 0 1 2 1 14139.86 0.0105 2 1 2 5 4 1 0 1 4 3 14139.67 0.0091 2 1 2 5 4 1 0 1 4 5 14139.61 0.0036 2 1 2 3 3 1 0 1 3 3 14139.61 -0.0146 2 1 1 5 5 2 1 2 4 4 7712.085 -0.0142 2 1 1 3 3 2 1 2 2 2 7711.826 -0.0318 2 1 2 3 2 1 0 1 3 2 14139.5 0.0096 2 1 2 2 1 1 0 1 2 1 14139.37 -0.0136 2 1 1 1 1 2 0 2 1 2 7762.598 0.0282 2 1 1 2 1 2 0 2 1 1 7762.794 -0.0088 2 1 1 2 3 2 0 2 1 2 7762.794 -0.0026 2 1 1 5 5 2 0 2 5 5 7763.01 -0.0086 2 1 1 3 3 2 0 2 1 2 7763.14 0.0132 2 1 1 1 2 2 0 2 2 3 7763.256 0.0291 2 1 1 1 0 2 0 2 2 1 7763.317 -0.0176 2 1 1 4 4 2 0 2 5 5 7763.585 0.0086 2 0 2 3 3 1 1 1 3 2 13645.35 -0.0121 354 2 0 2 5 5 1 1 1 4 4 13646.02 0.0297 2 0 2 1 0 1 1 1 2 1 13646.23 -0.0145 2 0 2 5 4 1 1 1 4 5 13645.9 0.0269 2 0 2 1 2 1 1 1 2 2 13646.27 0.0028 2 0 2 5 4 1 1 1 2 3 13645.54 -0.0197 Table 23. Azaborine line list for HsBll_N14DC4' Frequencies are given in MHz. J' Ka' Kc' J" Ka" Kc" obs 1 0 1 0 0 0 7728.933 1 1 1 0 0 0 8312.632 2 0 2 1 0 1 13557.518 B.2A. Supplemental in/ormation/or Chapter III, section 3.5 Protein expression, purification and crystallization. The T4lysozyme mutant L99A was constructed in the cysteine-free pseudo wide-type form as reported previously.47 Protein was expressed in the E. coli RRI strain. In brief, the bacteria were grown in 4.0 liters of LB media with ampicillin (100 mg/liter) at 37°C within an agitating fermentor (250 rpm) with filtered air supply. When the optical density of the broth reached 0.6 at 600mm, the temperature and agitating speed were lowered to 28°C and 150 rpm, and isopropyl-~-D-l-thiogalactopyranoside(IPTG) was added in a final concentration of 1.0 mM to induce the protein expression. After 5 hours induction, the 4.0 liters of culture was moved to a 4L beaker. 20 ml ofO.5M EDTA, pH 8.0, was added and the culture was stirred at room temperature for Ih. The solution becomes very viscous and 20 ml of 1M MgCh was added, followed by 20 mg of DNaseI. The solution was stirred till the viscosity lowered to normal. The solution was then spun and the supernatant collected. The supernatant was dialyzed against nano-pure water until the conductivity was less than 4.0 milli-Siemens and the 355 pH was adjusted to 7.0±0.5. The solution was then loaded onto a CM Sepharose CL-6B (Pharmacia) column, pre-equilibrated with equilibration buffer of 50 mM Tris, 1 mM EDTA, pH 7.3, by gravity feed, and washed by 100ml of equilibration buffer. The column was then eluted by an 800 mllinear gradient between 50 mM NaCI and 300 mM NaCI within the equilibration buffer, and the fractions were collected. The fractions containing T4lysozyme mutant L99A were pooled and dialyzed against 50 mM sodium phosphate, 0.02% NaN3, pH 5.8 buffer, and loaded onto a column of3 ml SP Sephadex C-50 (Pharmacia), and washed with 20 ml of the same buffer. The protein was then directly eluted by and stored in the harvesting buffer (100 mM sodium phosphate, 550 mM NaCl, 0.02% NaN3, pH 6.5). The protein concentration was adjusted to 40 mg/ml for crystallization. The crystals were obtained by vapor-diffusion hanging-drop method. The protein solution (5 IJ.I) was mixed with equal volume of reservoir solution (2.0-2.2 M sodium/potassium phosphate, pH 6.9, 50 mM 2-mercaptoethanol, 50 mM 2- hydroxyethyl disulfide), and equilibrated against 1 ml of the reservoir solution. Crystals normally grew to their maximum size in 2 weeks. Complex preparation. The protein complexes withl, 15 (see Chapter II, Table 2), benzene, and ethylbenzene were prepared by vapor diffusion method. To remove trace amount of oxygen in the crystals, the soaking buffer around the crystals was exchanged with the pre-deoxygenated reservoir buffer 3 times within a thin glass tube in the glove chamber with ]'h protection. The ligand (~15 mg) was then added and sealed in the glass tube. The sample was allowed to equilibrate at 4°C for 3 days. For the 356 benzene and ethylbenzene complexes, a similar protocol was followed except there was no need for N2 protection. Data collection, structure determination and refinement. Prior to X-ray data collection the crystals were flash-frozen in liquid nitrogen with protection ofN-paratone (Hampton Research). To avoid loss or potential oxidation of the ligand, the time from removal of the crystal from the sealed tube to mounting and freezing did not exceed 5 min. Data for T4lysozyme complexed with 15 were collected on beamline ID-23-B at the Advanced Photon Source, Argonne, IL, and for the complex with 1, benzene, and ethylbenzene were collected from beamline 5.0.2 at the Advanced Light Source, Berkeley, CA. Both datasets were to 1.25 A resolution. For each dataset, the low- and high-resolution data were collected with sweeps of 1 sec and 10 sec exposure time per degree, respectively. Data were processed and merged with HKL2000,48 and the structures were isomorphous with wildtype lysozyme. The ligand-free T4lysozyme L99A structure (PDB code: 3DMV) was used as the starting model for refinement with all solvent molecules removed. The refinements were done using the CCP4 package49 and graphics modeling with COOT.5o Coordinates for the ligands were introduced into the cavity at the final stage of the refinement, with placement based on the Fo-Fc maps. Table 24. X-ray data collection and structure refmement statistics for 15 and ethylbenzene Ligand 15 Ethylbenzene Data collection Beam line Wavelength (A) Space group ID-23-B, APS 1.0332 5.02, ALS 0.9791 Cell constants (A) Resolution (A) Completeness (%) l/s(1) Rmerge (%) Refinement Resolution (A) R a = b = 59.9, c = 95.47 52-1.25 (1.27-1.25) 99.1 (88.1) 34.9 (8.8) 5.3 (15.8) 52.0-1.25 0.163 a = b = 59.83, c = 95.60 52-1.25 (1.27-1.25) 99.9 (100.0) 44.1 (9.9) 5.2(22.1) 52.0-1.25 0.162 357 Rfree 0.182 0.182 Numbers in parentheses give the values for the outermost shell of data. Table 25. X-ray data collection and structure refmement statistics for 1 and benzene Ligand 1 Benzene Data collection Beam line Wavelength (A) Space group Cell constants (A) Resolution (A) Completeness (%) 1/s(1) Rmerge (%) Refinement 5.0.2, ALS 5.0.2, ALS 0.9791 0.9791 P322l P322l a = b = 59.90, c = 95.44 a = b = 60.00, c = 95.65 52-1.25 (1.27-1.25) 52-1.25 (1.27-1.25) 99.0 (100.0) 100.0 (100.0) 33.6 (9.1) 34.3 (10.7) 7.1 (26.9) 6.7 (26.7) Resolution (A) 52.0-1.25 52.0-1.25 R 0.170 0.170 358 Rfree 0.190 0.194 Numbers in parentheses give the values for the outermost shell of data. 359 APPENDIXC SYNTHESIS AND CHARACTERIZATION OF TOLAN ANALOGS AND DIYNE SCAFFOLDS C.l. Introduction The interest in conjugated organic molecules has grown significantly over the last several decades. The incorporation of boron in conjugated materials has been shown to impart unique properties relative to their carbonaceous analogs. 1,2 The fundamental consequences of replacing CC units with BN units in tolan derivatives provides a glimpse at the potential of 1,2-azaborine heterocycles in materials applications. C.2. Experimental C.2.I. General All oxygen- and moisture-sensitive manipulations were carried out under an inert atmosphere using either standard Schlenk techniques or a glove box. THF, EhO, CH2Cb, and pentane were purified by passing through a neutral alumina column under argon. Cyclohexene was dried over CaR2 and distilled under N2 prior to use. Trisacetonitrile(tricarbonyl)chromium(O) was purchased from Acros or Aldrich and used as received. All other chemicals and solvents were purchased (Aldrich or 360 Strem) and used as received. Silica gel (230-400 mesh) was heated under vacuum in a 200 °C sand bath for 12 hours. Flash chromatography was performed with this silica gel under an inert atmosphere. lIB NMR spectra were recorded on a Varian UnityIInova 600 spectrometer at ambient temperature. IH NMR spectra were recorded on a Varian Unity/Inova 300 or Varian Unity/Inova 600 spectrometer. 13C NMR spectra were recorded on a Varian Unity/Inova 300 or Varian Unity/Inova 500 spectrometer. COSY and HETCOR NMR spectroscopy was performed on a Varian Unity/Inova 300 spectrometer. liB NMR spectra were externally referenced to BF3-Et20 (~ 0). IR spectra were recorded on a Nicolet Magna 550 FT-IR instrument with OMNIC software. UV-Vis spectra were recorded on an Agilent 8453 spectrometer with ChemStation software. Fluorescence spectra were recorded on a Horiba Jobin-Yvon Fluoromax 4 fluorometer. High-resolution mass spectroscopy data were obtained at the Mass Spectroscopy Facilities and Services Core of the Environmental Health Sciences Center at Oregon State University. Financial support for this facility has been furnished in part by the National Institute ofEnvironmental Health Sciences, NIH (P30 ES00210). C.2.2. Supplemental information for Chapter IV, section 4.3 Synthesis of Compound 4. 1,2-Azaborine 3 (0.500 g, 2.20 mmol) and Et20 (20 mL) were combined in a flask and cooled to -10°C, whereupon phenylethylnylmagnesium bromide (0.7 M in THF; 3.45 mL, 2.42 mmol) was added 361 dropwise with stirring. The flask was allowed to warm to rt, whereupon approximately one-half of the solvent was removed under reduced pressure. Solids were filtered, and the remaining solvents were removed under reduced pressure. Column chromatography (EtzO/pentane) yielded 4 as a white, crystalline solid (0.490 g, 76%). IH NMR (300 MHz, CH2Ch): () 7.60 (dd, 3JHH = 11.2,5.6 Hz, IH), 7.51 (m,2H), 7.35 (m, 4H), 6.90 (d, 3JHH = 11.1 Hz, IH), 6.40 (app t, 3JHH = 6.4 Hz, IH), 0.95 (s, 9H), 0.63 (s, 6H). l3C NMR (75 MHz, CD2Ch): () 144.0, 139.3, 134 (br), 132.6, 131.9, 128.9, 128.8, 124.7, 112.8,27.0, 19.6, -1.9. liB NMR (192.5 MHz, CD2Ch): () 29.3. FTIR (thin film)3065,3031,2956,2929,2884,2858,2175, 1602, 1504, 1490, 1470, 1452, 1391, 1363,1274,1253,1194,1126, 1070, 1017,987,938,913,843,822,786,710,690,626 em-I. HRMS (El) calcd for CISH24BNSi (M+) 293.17711, found 293.17778. Compound 5. A vial was charged with a solution of 4 (0.500 g, 1.70 mmol in 30 mL THF) and (MeCN)3Cr(CO)3 (0.663 g, 2.56 mmol) and stirred at rt for 1 h. Solvents were removed and column chromatography was performed (CH2Ch/pentane) which provided 5 as a red, crystalline solid (0.667 g, 91%). IH NMR (300 MHz, CH2Ch): () 7.52 (m, 2H), 7.37 (m, 3H), 6.03 (dd, 3JHH= 7.9, 5.2 Hz, 2H), 5.23 (app t, 3JHH = 5.8 Hz, IH), 4.74 (d, 3JHH = 9.7 Hz, IH), 1.00 (s, 9H), 0.73 (s, 3H), 0.46 (s, 3H). l3C NMR (75 MHz, CD2Ch): () 230.6, 132.1, 129.5, 129.0, 123.6, 108.4,103.8,88 (br), 83.4,27.1,20.2, -1.1, -3.8. lIB NMR (96.3 MHz, CD2Ch): () 14.3. FTIR (CH2Ch) 1971, 1902, 1879 em-I. HRMS (El) calcd for C21H24BNSiCr03 (M+) 429.10237, found 429.10066. Compound 6. A vial was charged with a solution of 5 (0.667 g, 1.55 mmol in 10 362 mL THF) and cooled to -20 cC. A solution ofHF-pyridine (0.5 M in THF; 3.1 mL, 1.55 mmol) was added dropwise. The reaction was allowed to warm to rt and stirred for 10 min. Solvents were removed and column chromatography was performed (CH2Clz/pentane) which provided 6 as an orange-red solid (0.416 g, 85%). lH NMR (300 MHz, CH2Ch): 67.52 (m, 2H), 7.34 (m, 3H), 6.15 (app t, 3JHH = 5.3 Hz, 2H), 5.91 (dd, 3JHH = 8.6,6.2 Hz, 1H), 5.34 (br, 1H), 5.26 (dd, 3J HH = 7.2,5.0 Hz, 1H), 4.76 (d, 3JHH = 5.5 Hz). BC NMR (75 MHz, CD2Clz): 6230.0, 132.6, 129.7, 129.0, 122.9, 107.9,98.6,86 (br), 82.1. liB NMR (192.5 MHz, CD2Clz): 611.7. FTIR (CH2Clz) 3361, 2185,1976,1906,1880 em-I. HRMS (El) calcd for CIsHlOBNCr03 (M) 315.01589, found 315.01578. Synthesis ofBN toIan 1. Complex 6 (0.383 g, 1.22 mmol) and MeCN (10 mL) were combined in a vial and stirred at rt for 12 h. Approximately two-thirds of the solvent was removed under reduced pressure. Column chromatography (CH2Ch/pentane) provided BN tolan 1 as a white, crystalline solid (0.198 g, 91 %). IH NMR (300 MHz, CH2Clz): 6 8.44 (br, 1H), 7.76 (dd, 3JHH = 10.8,6.7 Hz, 1R), 7.59 (m, 2H), 7.40 (m, 3R), 7.00 (d, 3JHH = ILl Hz, 1H), 6.44 (app t, 3JHH = 6.5 Hz, 1H). BC NMR (125.8 MHz, CD2Ch): 6 145.1, 134.9, 132.4, 132 (br), 129.0, 124.1, 111.9, 104.8,84 (br). liB NMR (192.5 MHz, CD2Clz): 625.8. FTIR (thin film) 3380, 3140, 3075,3049,3027,2178,1606,1538,1487,1460,1440, 1421, 1349, 1265, 1235, 1213, 1191, 1126, 1108, 1080,995,842, 793, 760, 733, 692, 681 em-I. HRMS (El) calcd for CI2HlOBN (M+) 179.09063, found 179.09122. Compound 8. Ethylmagnesium bromide (1M in THF; 1.96 mL, 1.96 mmol) and 363 ethynylmagnesium bromide (0.5M in THF; 3.91 mL, 1.96 mmol) were combined in a vial and stirred at rt for 30 minutes during which time significant gas evolution was observed. The reaction was stirred an additional 12 h, then added to a solution of3 (0.890 g, 3.91 mmol in 10 mL THF) with stirring at rt. The reaction was stirred an additional 48 h, at which point the solvent was removed. Column chromatography (CH2Ch/pentane) yielded 8 as a light-yellow solid (0.732 g, 91 %). IH NMR(300 MHz, CH2Ch): 07.58 (dd, 3JHH = 11.0, 6.1 Hz, 1H), 7.28 (d, 3JHH = 6.3 Hz, 1H), 6.82 (d, 3JHH = 11.2 Hz, 1B), 6.38 (app t, 3JHH = 6.3, 6.1 Hz, 1H). BC NMR (75 MHz, CD2Ch): 0 143.7, 139.3, 122 (hr), 112.5,27.0, 19.6, -1.8. liB NMR (192.5 MHz, CD2Ch): 028.7. FTlR (thin film) 3007, 2927, 2882, 2857, 1875, 1600, 1503, 1467, 1450,1389,1364,1270,1257,1216,1173, 1153, 1097,989,938,842,822,810,739,705, 694,634 em-I. HRMS (El) calcd for C22H3sB2N2Si2 (M+) 408.27597, found 408.27775. Compound 10. To a stirred solution of8 (0.732 g, 1.79 mmol in 18 mL THF) was added (MeCN)3Cr(CO)3 (0.976 g, 3.76 mmol). The reaction was stirred at rt for 1 h, then solvents were removed and column chromatography (CH2Ch/pentane) was performed to give a mixture of9 and 10. The mixture was taken up in THF (15 mL) and (MeCN)3Cr(CO)3 (0.300 g, 1.16 mmol) was added. The reaction was stirred at rt for 1 h. Solvents were removed and the crude material was subjected to column chromatograpy (CH2Ch/pentane) which provided 10 as an orange-red, crystalline solid (0.365 g, 30%). IH NMR (300 MHz, CH2Ch): 05.9-6.0 (m, 2H), 5.19 (app t, 3JHH = 6.1 Hz, 1H), 4.61 (d, 3JHH = 6.2 Hz, 1H). BC NMR (75 MHz, CD2Ch): 0230.3, 108.0, 103.5,83.3, 27.2, -0.8, -3.9. liB NMR (192.5 MHz, CD2Ch): 0 13.6. FTlR (CH2Ch) 1971, 1899 (hr) 364 -I cm . Compound 11. A solution of complex 10 (0.228 g, 0.335 mmol in 15 mL) was cooled to -20°C, whereupon HF-pyridine (0.5 Min THF; 1.34 mL, 0.67 mmol) was added dropwise. The reaction was kept at -20°C for 30 min., then allowed to warm to rt. Solvents were removed to provide a crude mixture which was used directly in the preparation of2. Synthesis of BN tolan 2. The crude material containing complex 11 was combined in a vial with MeCN (5 mL) and stirred at rt for 10 min. Solvents were removed, whereupon column chromatograpy (Et20/pentane) gave 2 as a white, crystalline solid (0.028 g, 46.5% from 10). IH NMR (300 MHz, CH2Ch): ~ 8.43 (br, 1H), 7.71 (dd, 3JHH = 10.8,6.6 Hz, 1H), 7.36 (app t, 3JHH = 7.2 Hz, 1H), 6.89 (d, 3JHH = 11.1 Hz, 1H), 6.40 (app t, 3JHH = 6.5 Hz). I3C NMR (125.8 MHz, CD2Ch): ~ 145.1, 134.8, 131 (br), 111.8. lIB NMR (192.5 MHz, CD2Ch): ~ 25.4. FTIR (CH2Ch) 3370, 3091, 3053, 3031,2978, 1611, 1532, 1464, 1420, 1352, 1223, 1202, 1151, 1082,998,852, 740, 677 cm-I• HRMS (El) calcd for ClOHlOB2N2 (M+) 180.10301, found 180.10330. 365 Figure I. ORTEP illustration of L with thermal ellipsoids drawn at the 35% level. X-ray Crystal Structure Detet'mination. Crystals of 1 suitable for X-ray diffraction were obtained by evaporation of a solution of t in EbO. Oitfraction intensity data were collected with a Bruker Smart Apex CCO diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2. Allnon-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6. I0) program package (G.Sheldrick, Bruker XRO, Madison, WI). Crystallographic data and some details of data collection and crystal structure reiinement for Cd-1 IOBN are given in the following tables. Table l. Crystal data and structure refinement for liun. Identification code Empirical formula liun C I2 H10 BN u= 90°. Fonnula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 25.0000 Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters Goodness-of-fit on F2 Final R indices [I>2sigma(I)] R indices (all data) Absolute structure parameter Largest diff. peak and hole 179.02 173(2) K 0.71073 ~ Orthorhombic Fdd2 a = 23.388(11) A b = 31.934(15) A c = 5.423(3) A 4051(3) A3 16 1.174 Mg/m3 0.067 mm-1 1504 0.21 x 0.12 x 0.02 mm3 2.16 to 25.00°. -27<=h<=27, -37<=k<=37, -6<=1<=6 8757 1791 [R(int) = 0.0942] 100.0 % Semi-empirical from equivalents 0.9987 and 0.9860 Full-matrix least-squares on F2 1791/1/167 1.034 R1 = 0.0571, wR2 = 0.1043 R1 = 0.0946, wR2 = 0.1198 0(6) 0.143 and -0.161 e.~-3 366 Table 2. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (Nx 103) for Hun. U(eq) is defmed as one third of the trace of the orthogonalized Uij tensor. N(1) B(1) C(1) x y z 601(1) 1001(1) 4888(6) 122(2) 917(1) 3334(8) 1013(2) 1296(1) 4348(8) U(eq) 41(1) 33(1) 42(1) 367 C(2) 974(2) 1525(1) 2256(7) 40(1) C(3) 514(2) 1462(1) 595(8) 42(1) C(4) 95(2) 1173(1) 1045(7) 41(1) C(5) -319(1) 596(1) 4301(7) 37(1) C(6) -665(1) 352(1) 5158(7) 36(1) C(7) -1077(1) 65(1) 6161(6) 33(1) C(8) -965(2) -154(1) 8367(7) 40(1) C(9) -1367(2) -438(1) 9266(8) 49(1) C(10) -1877(2) -502(1) 8034(9) 55(1) C(11) -1999(2) -280(1) 5913(9) 49(1) C(12) -1601(2) 0(1) 4952(7) 41(1) Table 3. Bond lengths [A] and angles [0] for Hun. N(1)-C(1) 1.380(4) N(1)-B(1) 1.427(5) N(1)-H(1N) 0.92(5) B(1)-C(4) 1.488(5) B(1)-C(5) 1.545(5) C(1)-C(2) 1.352(5) C(1)-H(1) 1.04(4) C(2)-C(3) 1.417(5) C(2)-H(2) 0.95(3) C(3)-C(4) 1.368(5) C(3)-H(3) 0.91(3) C(4)-H(4) 0.93(3) C(5)-C(6) 1.216(4) C(6)-C(7) 1.436(5) C(7)-C(12) 1.406(5) C(7)-C(8) 1.410(5) C(8)-C(9) 1.395(5) C(8)-H(8) 0.95(5) C(9)-C(10) 1.383(6) C(9)-H(9) 0.96(4) C(10)-C(11) 1.381(6) C(1 O)-H(1 0) 0.96(4) C(11)-C(12) 1.391(5) C(11)-H(11) 0.99(4) C(12)-H(12) 0.94(3) C(1)-N(1)-B(1) C(1)-N(1)-H(1N) B(l)-N(1)-H(1N) N(1)-B(1)-C(4) N(1)-B(1)-C(5) C(4)-B(1)-C(5) C(2)-C(1)-N(l) C(2)-C(1)-H(1) N(1 )-C(1)-H(1) C(1 )-C(2)-C(3) C(1 )-C(2)-H(2) C(3)-C(2)-H(2) 123.5(3) 120(3) 116(3) 114.9(3) 116.6(3) 128.3(3) 120.0(4) 130(2) 110(2) 120.5(3) 115(2) 125(2) C(4)-C(3)-C(2) 121.7(4) C(4)-C(3)-H(3) 118.8(19) C(2)-C(3)-H(3) 119.4(19) C(3)-C(4)-B(1) 119.4(4) C(3)-C(4)-H(4) 121(2) B(1)-C(4)-H(4) 120(2) C(6)-C(5)-B(1) 177.2(4) C(5)-C(6)-C(7) 179.7(4) C(12)-C(7)-C(8) 119.0(3) C(12)-C(7)-C(6) 120.1(3) C(8)-C(7)-C(6) 120.9(3) C(9)-C(8)-C(7) 119.6(4) C(9)-C(8)-H(8) 117(3) C(7)-C(8)-H(8) 123(3) C(10)-C(9)-C(8) 120.6(4) C(10)-C(9)-H(9) 123(2) C(8)-C(9)-H(9) 116(2) C(11)-C(10)-C(9) 120.2(4) C(11)-C(10)-H(10) 119(3) C(9)-C(10)-H(10) 120(3) C(10)-C(11)-C(12) 120.3(4) C(10)-C(1I)-H(11) 124(2) C(12)-C(11 )-H(1 1) 115(2) C(11)-C(12)-C(7) 120.2(4) C(11)-C(12)-H(12) 124(2) C(7)-C(12)-H(12) 116(2) Symmetry transfonnations used to generate equivalent atoms: Table 4. Anisotropic displacement parameters (A2x 103)for Hun. The anisotropic displacement factor exponent takes the fonn: -2:rt2[ h2a*2Ull + ... + 2 h k a* b* Ul2] Ull U22 U33 U23 Ul3 Ul2 N(1) 49(2) 30(2) 43(2) 8(2) -6(2) -7(2) B(1) 32(2) 19(2) 47(2) -2(2) -1(2) 4(2) C(1) 47(3) 34(2) 46(3) 4(2) -2(2) -13(2) C(2) 42(2) 26(2) 52(2) 2(2) 6(2) -5(2) C(3) 46(2) 35(2) 45(3) 11(2) 3(2) 4(2) C(4) 37(2) 36(2) 48(3) 1(2) -3(2) 0(2) C(5) 36(2) 27(2) 48(2) 0(2) -1(2) 6(2) C(6) 41(2) 25(2) 43(2) -2(2) -2(2) 6(2) C(7) 39(2) 19(2) 41(2) -6(2) 4(2) 1(1) C(8) 55(3) 21(2) 44(2) -6(2) 5(2) 7(2) C(9) 77(3) 28(2) 42(3) 4(2) 19(2) 3(2) C(10) 57(3) 35(2) 73(3) -6(2) 27(3) -7(2) C(11) 43(2) 36(2) 66(3) -7(2) 8(2) -11(2) C(12) 46(2) 28(2) 49(3) -5(2) 7(2) -3(2) Table 5. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2x 103) for Hun. 368 H(1N) H(1) x 625(18) 1305(18) y 847(13) 1315(12) z 6320(90) 5800(80) U(eq) 95(17) 86(14) 369 H(2) 1276(13) 1720(9) 2020(60) 38(9) H(3) 510(12) 1603(9) -870(60) 27(9) H(4) -198(13) 1130(9) -80(70) 37(10) H(8) -627(19) -114(13) 9310(90) 86(16) H(9) -1282(15) -564(11) 10830(80) 53(11) H(10) -2172(17) -674(12) 8760(80) 74(14) H(11) -2353(14) -314(10) 4930(80) 51(11) H(12) -1658(13) 156(9) 3510(70) 39(10) Table 6. Torsion angles [0] for Hu72. C(1)-N(1)-B(1)-C(4) C(1 )-N(1)-B(1 )-C(5) B(1)-N(1)-C(1)-C(2) N(1 )-C(1 )-C(2)-C(3) CO )-C(2)-C(3)-C(4) C(2)-C(3)-C(4)-B(1 ) N(1)-B(1)-C(4)-C(3) C(5)-B(1)-C(4)-C(3) N(1 )-B(1)-C(5)-C(6) C(4)-B(1)-C(5)-C(6) B(1)-C(5)-C(6)-C(7) C(5)-C(6)-C(7)-C(12) C(5)-C(6)-C(7)-C(8) C(12)-C(7)-C(8)-C(9) C(6)-C(7)-C(8)-C(9) C(7)-C(8)-C(9)-C(10) C(8)-C(9)-C(1 0)-C01) C(9)-C(1 0)-C(11)-C(12) C(1O)-C(11 )-C(12)-C(7) C(8)-C(7)-C(12)-C(11 ) C(6)-C(7)-C(12)-C(11) Symmetry transformations used to generate equivalent atoms: 0.2(5) -176.1(3) 0.1(5) -0.4(5) 0.3(6) 0.0(5) -0.2(5) 175.6(4) 47(7) -129(7) 120(100) 6(92) -173(100) 1.9(4) -178.5(3) -1.0(5) -1.0(6) 2.1(6) -1.2(5) -0.8(5) 179.6(3) 370 11 111 ( ~) c ) (:;1 (F:~~I" II,:(! r (': I' , ~,rl'J "F""'-\ ..i\~ 'j} ,I:) (,)~l'; :111 (I> I ql" Figure 2. ORTEP illustration 01'8, with thermal ellipsoids drawn at the 35% probability level. Hydrogen atoms have been omitted for clarity, X-ray Crystal Structul"e Determination. Crystals of 8 suitable for X-ray diffraction were obtained by evaporation of a solution of 8 in Et20. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods. completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2. All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic tber11131 paj"~lineters. The Fluck paranletcr is 0.00(8). /;11 soft\vare and SOLlfceS scaUering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal 371 structure refinement for C22H3SB2N2Sh are given in the following tables. Table 7. Crystal data and structure refmement for 8 (liu49). Monoclinic 13= 101.892(2t· y =900 • Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 27.000 Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters Goodness-of-fit on F2 Final R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole liu49 C22 H38 B2 N2 Si2 408.34 173(2) K 0.71073 A P2(1)/n a= 11.3135(12) A b = 8.3715(9) A c = 13.7353(14) A 1273.0(2) A3 2 1.065 Mg/m3 0.149 mm-1 444 0.19 x 0.12 x 0.05 mm3 2.13 to 27.000 • -14<=h<=14, -10<=k<=1O, -17<=1<=17 13631 2780 [R(int) = 0.0429] 99.9% Semi-empirical from equivalents 0.9926 and 0.9722 Full-matrix least-squares on F2 2780/0/203 1.074 R1 = 0.0520, wR2 = 0.1194 R1 = 0.0712, wR2 = 0.1301 0.340 and -0.165 e.A-3 Table 8. Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A2x 103) for liu49. U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. 372 Si(l) N(l) B(l) C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(ll) x y z 7763(1) 2417(1) 5157(1) 6997(1) 2347(2) 6184(1) 5893(2) 1485(3) 6194(2) 5284(2) 437(2) 5312( 1) 5356(2) 1622(3) 7109(1) 5916(2) 2529(3) 7882(2) 6994(2) 3330(3) 7833(2) 7489(2) 3234(3) 7019(2) 7796(3) 419(3) 4574(2) 9363(2) 2986(4) 5673(2) 7014(2) 3968(3) 4241(2) 5686(3) 3583(4) 3828(2) 7683(3) 4052(4) 3377(2) 7109(3) 5618(3) 4743(2) U(eq) 27(1) 26(1) 26(1) 28(1) 32(1) 39(1) 47(1) 40(1) 39(1) 47(1) 35(1) 56(1) 54(1) 55(1) Table 9. Bond lengths [A] and angles [0] for liu49. Si(l)-N(1) 1.8010(16) Si(1)-C(6) 1.858(2) Si(1)-C(7) 1.865(3) Si(1)-C(8) 1.884(2) N(l)-C(5) 1.384(3) N(1)-B(1) 1.445(3) B(1)-C(2) 1.508(3) B(1)-C(1) 1.539(3) C(1)-C(1)#l 1.206(4) C(2)-C(3) 1.352(3) C(2)-H(2) 0.97(2) C(3)-C(4) 1.405(3) C(3)-H(3) 0.93(2) C(4)-C(5) 1.352(3) C(4)-H(4) 0.93(3) C(5)-H(5) 0.98(2) C(6)-H(6A) 0.92(4) C(6)-H(6B) 0.92(3) C(6)-H(6C) 0.95(3) C(7)-H(7A) 0.99(3) C(7)-H(7B) 0.90(3) C(7)-H(7C) 0.94(4) C(8)-C(9) 1.527(3) C(8)-C(10) 1.536(3) C(8)-C(11) 1.537(3) C(9)-H(9A) 0.98(3) C(9)-H(9B) 0.99(3) C(9)-H(9C) 0.92(3) C(10)-H(10A) 1.04(3) C(10)-H(10B) 0.98(3) C(10)-H(10C) 0.98(3) C(11)-H(11A) 0.96(3) 373 C(11)-H(11B) 0.98(3) C(11)-H(11C) 0.95(3) N(1)-Si(1)-C(6) 111.34(10) N(1)-Si(1)-C(7) 107.24(10) C(6)-Si(1)-C(7) 106.84(14) N(1)-Si(1)-C(8) 108.84(9) C(6)-Si(1)-C(8) 112.24(11) C(7)-Si(1)-C(8) 110.21(12) C(5)-N(1)-B(1) 117.42(16) C(5)-N(1)-Si(1) 117.09(13) B(1)-N(1)-Si(1) 125.46(13) N(1)-B(1)-C(2) 117.90(18) N(1)-B(l)-C(1) 121.65(16) C(2)-B(l)-C(1) 120.45(17) C(l)#l-C(1)-B(1) 172.5(2) C(3)-C(2)-B(1) 119.53(19) C(3)-C(2)-H(2) 120.1(13) B(1)-C(2)-H(2) 120.3(13) C(2)-C(3)-C(4) 120.1(2) C(2)-C(3)-H(3) 122.2(15) C(4)-C(3)-H(3) 117.6(15) C(5)-C(4)-C(3) 121.5(2) C(5)-C(4)-H(4) 117.8(17) C(3)-C(4)-H(4) 120.7(17) C(4)-C(5)-N(1) 123.6(2) C(4)-C(5)-H(5) 120.4(13) N(1)-C(5)-H(5) 116.0(13) Si(1)-C(6)-H(6A) 112(2) Si(l)-C(6)-H(6B) 113(2) H(6A)-C(6)-H(6B) 112(3) Si(1)-C(6)-H(6C) 107.5(16) H(6A)-C(6)-H(6C) 100(3) H(6B)-C(6)-H(6C) 112(2) Si(1)-C(7)-H(7A) 109.5(16) Si(l)-C(7)-H(7B) 115.7(19) H(7A)-C(7)-H(7B) 106(2) Si(1)-C(7)-H(7C) 109(2) H(7A)-C(7)-H(7C) 106(3) H(7B)-C(7)-H(7C) 109(3) C(9)-C(8)-C(10) 109.1(2) C(9)-C(8)-C(11) 109.2(2) C(10)-C(8)-C(11) 107.8(2) C(9)-C(8)-Si(1) 112.04(16) C(1 0)-C(8)-Si(1) 108.81(17) C(11)-C(8)-Si(1) 109.85(17) C(8)-C(9)-H(9A) 112.7(17) C(8)-C(9)-H(9B) 110.9(17) H(9A)-C(9)-H(9B) 109(2) C(8)-C(9)-H(9C) 111.4(18) H(9A)-C(9)-H(9C) 107(2) H(9B)-C(9)-H(9C) 105(2) C(8)-C(10)-H(1OA) 108.7(17) C(8)-C(10)-H(1 OB) 110.7(17) H(10A)-C(10)-H(10B) 106(2) C(8)-C(10)-H(10C) 115.0(17) H(1 OA)-C(1 O)-H(1 OC) 104(2) H(10B)-C(10)-H(10C) 112(2) C(8)-C(11)-H(11A) 111.4(19) C(8)-C(11)-H(11B) 110(2) H(11A)-C(11)-H(11 B) 107(3) C(8)-C(11)-H(11 C) 108.1 (19) H(11A)-C(11)-H(11 C) 106(3) H(1lB)-C(11)-H(11C) 114(3) Symmetry transformations used to generate equivalent atoms: #1 -x+1,-y,-z+1 Table 10. Anisotropic displacement parameters (A2x 1()3)for liu49. The anisotropic displacement factor exponent takes the form: _2p2[ h2a*2Ull + ... + 2 h k a* b* U12 ] Si(1) 27(1) 33(1) 24(1) -1(1) 9(1) -4(1) N(1) 30(1) 29(1) 20(1) -2(1) 6(1) -5(1) B(1) 29(1) 26(1) 21(1) 3(1) 4(1) -2(1) C(1) 28(1) 34(1) 24(1) 1(1) 9(1) -5(1) C(2) 34(1) 37(1) 27(1) 1(1) 10(1) -5(1) C(3) 52(1) 45(1) 24(1) -5(1) 16(1) -6(1) C(4) 61(2) 54(2) 28(1) -17(1) 14(1) -22(1) C(5) 45(1) 44(1) 31(1) -10(1) 11(1) -19(1) C(6) 45(1) 40(1) 38(1) -5(1) 20(1) 2(1) C(7) 32(1) 67(2) 43(1) -6(1) 10(1) -8(1) C(8) 37(1) 39(1) 30(1) 6(1) 12(1) -1(1) C(9) 44(2) 65(2) 54(2) 27(2) -2(1) -3(1) C(10) 69(2) 60(2) 39(1) 12(1) 25(1) -4(2) C(11) 71(2) 40(2) 57(2) 5(1) 17(2) 7(1) Table 11. Hydrogen coordinates ( x 1()4) and isotropic displacement parameters (A2x 1()3) for liu49. x y z U(eq) H(2) 4600(20) 1080(30) 7138(16) 40(6) H(3) 5590(20) 2700(30) 8440(18) 41(6) H(4) 7400(20) 3930(30) 8370(20) 68(8) H(5) 8260(20) 3770(30) 7007(16) 35(6) H(6A) 8170(30) -330(50) 5020(30) 110(13) H(6B) 7050(30) 90(40) 4240(20) 82(10) H(6C) 8350(20) 470(30) 4140(20) 58(8) H(7A) 9710(20) 2250(30) 6220(20) 62(8) H(7B) 9480(30) 3990(40) 5920(20) 66(9) H(7C) 9820(30) 2850(40) 5180(30) 89(11) H(9A) 5200(30) 3560(40) 4350(20) 69(9) H(9B) 5330(30) 4360(30) 3310(20) 66(8) H(9C) 5600(30) 2600(30) 3510(20) 55(8) H(10A) 7290(30) 4940(40) 2890(20) 77(9) H(10B) 7590(30) 3050(40) 3000(20) 68(9) H(10C) 8530(30) 4380(30) 3560(20) 67(9) H(11A) 6710(30) 6420(40) 4300(20) 80(10) 374 H(11B) H(11C) 7960(30) 6690(30) 5930(40) 5570(40) 4940(20) 5270(20) 85(11) 77(10) 375 Table 12. Torsion angles [0] for liu49. C(6)-Si(1)-N(1 )-C(5) C(7)-Si(1)-N(1 )-C(5) C(8)-Si(1)-N(1 )-C(5) C(6)-Si(1)-N(1)-B(1 ) C(7)-Si(1)-N(1)-B(1) C(8)-Si(1)-N(1)-B(1) C(5)-N(1 )-B(1 )-C(2) Si(1 )-N(1)-B(1)-C(2) C(5)-N(1 )-B(1)-C(1) Si(1 )-N(1)-B(1 )-C(1) N( 1)-B(l)-C(1 )-C(1)#l C(2)-B(1 )-C(l)-C(1)#1 N(1 )-B(1)-C(2)-C(3) C(1)-B(1 )-C(2)-C(3) B(1)-C(2)-C(3)-C(4) C(2)-C(3)-C(4)-C(5) C(3)-C(4)-C(5)-N(1) B(1)-N(1)-C(5)-C(4) Si(1)-N(1)-C(5)-C(4) N(1 )-Si(1 )-C(8)-C(9) C(6)-Si(1)-C(8)-C(9) C(7)-Si(1)-C(8)-C(9) N(1 )-Si(1 )-C(8)-C(1 0) C(6)-Si(1)-C(8)-C(10) C(7)-Si(1)-C(8)-C(10) N(1)-Si(1)-C(8)-C(11) C(6)-Si(1 )-C(8)-C(11) C(7)-Si(1)-C(8)-C(I1) Symmetry transformations used to generate equivalent atoms: #1 -x+l,-y,-z+1 139.95(18) 23.4(2) -95.81 (18) -42.3(2) -158.80(18) 81.98(17) 0.3(3) -177.52(14) -178.83(19) 3.4(3) 174(2) -5(2) -0.1(3) 179.0(2) -0.3(3) 0.7(4) -0.6(4) 0.1(3) 178.1(2) -60.5(2) 63.2(2) -177.8(2) 178.84(17) -57.5(2) 61.5(2) 61.1 (2) -175.23(18) -56.3(2) 376 I 11'/)(t ~I,'{,'';,' N~) ", 111) //' \ , \ .\ \ . I'- I, -~\ / ,-- \ "/ /. ,I '-, - \ ,~ I I,; / / /,\~! '\'/ /// .1 1, 0(3) I;~ 1\,'~c;.(11~\, ~{IIJV' J~OI1l 0(2) Figure 3, ORTEP illustrfltion of 10, with thermal ellipsoids clrawn at the 35% probabilit)' level, Hydrogen atoms have been omitted for clarity. X-ray Ct'ystaJ Stmcture Determination. Crystals of 10 suitable for X-ray diffraction were obtained by evaporation of a solution of JOin £t20. Diffraction intensity data were collected \-\lith a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure \,vas solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2. All non-H atoms were refined with anisotropic thermal parameters. H atoms \·vere found on the residual density map and refined with isotropic thefil1alIJdl ClllIl-L'--I::>. -;-;IC jidck parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for C2sH3SB2N206Siz are given in the following tables. Table 13. Crystal data and structure refinement for 10 (liu50). 377 Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 25.000 Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters Goodness-of-fit on F2 Final R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole liu50 CZ8 H38 Bz Crz Nz 0 6 Siz 680.40 173(2) K 0.71073 A Orthorhombic Pbca a = 12.8679(12) A b = 20.821(2) A c = 25.082(2) A 6719.9(11) A3 8 1.345 Mg/m3 0.759 mm-1 2832 0.12 x 0.04 x 0.02 mm3 1.62 to 25.000 • -15<=h<=15, -24<=k<=24, -29<=1<=29 52442 5928 [R(int) = 0.1524] 100.0 % Semi-empirical from equivalents 0.9850 and 0.9145 Full-matrix least-squares on F2 5928/0/379 1.031 R1 = 0.0610, wR2 = 0.1073 R1 = 0.1086, wR2 = 0.1262 0.412 and -0.367 e.A-3 378 Table 14. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (A2X 1()3) for liu50. V(eq) is defined as one third of the trace of the orthogonalized Vij tensor. x y z V(eq) Cr(l) 6961(1) 1763(1) 6635(1) 23(1) Cr(2) 7037(1) 419(1) 3540(1) 23(1) Si(1) 8380(1) 331(1) 6166(1) 24(1) Si(2) 7451(1) 2074(1) 3982(1) 26(1) 0(1) 7840(3) 2564(2) 5746(1) 49(1) 0(2) 6167(3) 2944(2) 7181 (1) 48(1) 0(3) 8953(3) 2022(2) 7214(1) 45(1) 0(4) 8613(3) -12(2) 4340(1) 40(1) 0(5) 7081(3) -902(2) 3071(1) 44(1) 0(6) 8790(3) 692(2) 2788(1) 52(1) N(1) 7186(3) 765(2) 6348(1) 20(1) N(2) 6620(3) 1372(2) 3864(1) 21(1) 8(1) 6447(4) 1050(2) 5962(2) 21(1) 8(2) 6272(4) 914(3) 4277(2) 22(1) C(1) 7495(4) 2256(2) 6080(2) 30(1) C(2) 6474(4) 2492(3) 6967(2) 32(1) C(3) 8195(4) 1906(2) 6991(2) 30(1) C(4) 7995(4) 159(2) 4033(2) 25(1) C(5) 7051(4) -388(3) 3249(2) 31(1) C(6) 8108(4) 610(2) 3081(2) 32(1) C(7) 6951(4) 781(2) 6894(2) 24(1) C(8) 6058(4) 1060(2) 7095(2) 26(1) C(9) 5366(4) 1390(2) 6755(2) 26(1) C(10) 5538(4) 1402(2) 6209(2) 26(1) C(1l) 8959(4) 726(2) 5578(2) 280) C(12) 9298(4) 396(3) 6740(2) 40(1) C(13) 8010(4) -529(2) 6053(2) 300) C(14) 7231(4) -597(2) 5589(2) 38(1) C(15) 8994(4) -911(3) 5909(2) 47(2) C(16) 7518(4) -818(2) 6555(2) 43(1) C(17) 6568(3) 1008(2) 5357(2) 23(1) C(18) 6510(3) 995(2) 4875(2) 21(1) C(19) 6253(4) 1303(2) 3343(2) 27(1) C(20) 5583(4) 814(2) 3194(2) 300) C(21) 5316(4) 320(2) 3554(2) 31(1) C(22) 5645(3) 351 (2) 4082(2) 26(1) C(23) 8432(4) 1878(2) 4498(2) 33(1) C(24) 8145(4) 2265(3) 3354(2) 45(2) C(25) 6561(4) 2748(2) 4174(2) 36(1) C(26) 5838(4) 2571(3) 4637(2) 50(2) C(27) 7243(5) 3321(3) 4344(2) 60(2) C(28) 5895(5) 2951(3) 3693(2) 65(2) Table 15. Bond lengths [A] and angles [0] for Iiu50. 379 Cr(l)-C(2) Cr(l)-C(3) Cr(l)-C(l) Cr(l)-C(7) Cr(l)-C(8) Cr(l)-C(9) Cr(l)-N(l) Cr(l)-C(lO) Cr(l)-B(l) Cr(2)-C(4) Cr(2)-C(5) Cr(2)-C(6) Cr(2)-C(l9) Cr(2)-N(2) Cr(2)-C(20) Cr(2)-C(21 ) Cr(2)-C(22) Cr(2)-B(2) Si(l)-N(l) Si(l)-C(ll) Si(l)-C(l2) Si(l)-C(l3) Si(2)-N(2) Si(2)-C(23) Si(2)-C(24) Si(2)-C(25) O(l)-C(l) O(2)-C(2) O(3)-C(3) O(4)-C(4) O(5)-C(5) O(6)-C(6) N(l)-C(7) N(l)-B(l) N(2)-C(19) N(2)-B(2) B(l)-C(lO) B(l)-C(l7) B(2)-C(22) B(2)-C(18) C(7)-C(8) C(7)-H(7A) C(8)-C(9) C(8)-H(8A) C(9)-C(l0) C(9)-H(9A) C(lO)-H(lOA) C(ll)-H(lIA) C(ll)-H(lIB) C(ll)-H(l1 C) C(l2)-H(l2A) C(l2)-H(l2B) 1.841 (5) 1.846(5) 1.859(5) 2.145(4) 2.196(5) 2.215(5) 2.217(4) 2.249(5) 2.341(5) 1.828(5) 1.831(5) 1.840(5) 2.156(5) 2.211(4) 2.221(5) 2.225(5) 2.253(4) 2.334(5) 1.840(4) 1.846(5) 1.866(5) 1.875(5) 1.834(4) 1.853(5) 1.854(5) 1.875(5) 1.146(5) 1.153(5) 1.151 (5) 1.163(5) 1.161(5) 1.156(6) 1.402(5) 1.481(6) 1.397(5) 1.477(6) 1.513(7) 1.529(7) 1.506(7) 1.540(7) 1.382(6) 1.0000 1.411(6) 1.0000 1.387(6) 1.0000 1.0000 0.9800 0.9800 0.9800 0.9800 0.9800 380 C(I2)-H(12C) 0.9800 C(I3)-C(16) 1.533(6) C(I3)-C(I5) 1.537(7) C(I3)-C(14) 1.542(7) C(I4)-H(14A) 0.9800 C(I4)-H(14B) 0.9800 C(14)-H(14C) 0.9800 C(I5)-H(15A) 0.9800 C(I5)-H(15B) 0.9800 C(I5)-H(15C) 0.9800 C(16)-H(16A) 0.9800 C(I6)-H(16B) 0.9800 C(I6)-H(16C) 0.9800 C(17)-C(18) 1.211 (6) C(19)-C(20) 1.387(6) C(I9)-H(19A) 1.0000 C(20)-C(21) 1.411 (7) C(20)-H(20A) 1.0000 C(21 )-C(22) 1.392(6) C(2l)-H(21A) 1.0000 C(22)-H(22A) 1.0000 C(23)-H(23A) 0.9800 C(23)-H(23B) 0.9800 C(23)-H(23C) 0.9800 C(24)-H(24A) 0.9800 C(24)-H(24B) 0.9800 C(24)-H(24C) 0.9800 C(25)-C(26) 1.533(7) C(25)-C(28) 1.539(7) C(25)-C(27) 1.539(7) C(26)-H(26A) 0.9800 C(26)-H(26B) 0.9800 C(26)-H(26C) 0.9800 C(27)-H(27A) 0.9800 C(27)-H(27B) 0.9800 C(27)-H(27C) 0.9800 C(28)-H(28A) 0.9800 C(28)-H(28B) 0.9800 C(28)-H(28C) 0.9800 C(2)-Cr(1)-C(3) 86.6(2) C(2)-Cr(1 )-C(1) 90.5(2) C(3)-Cr(1 )-C(1) 87.4(2) C(2)-Cr(1)-C(7) 130.25(19) C(3)-Cr(1 )-C(7) 90.7(2) C(l)-Cr(1)-C(7) 139.02(19) C(2)-Cr(1)-C(8) 97.5(2) C(3)-Cr(1)-C(8) 107.95(19) C(1)-Cr(1 )-C(8) 162.96(19) C(7)-Cr(1)-C(8) 37.12(17) C(2)-Cr(1)-C(9) 84.9(2) C(3)-Cr(1 )-C(9) 141.96(19) C(1 )-Cr(1)-C(9) 129.6(2) C(7)-Cr(1 )-C(9) C(8)-Cr(1)-C(9) C(2)-Cr(1 )-N(1) C(3)-Cr(1)-N(1) C(l)-Cr(l)-N(l) C(7)-Cr(1)-N(1) C(8)-Cr(1)-N(1) C(9)-Cr(1)-N(1) C(2)-Cr(1 )-C(10) C(3)-Cr( 1)-C(10) C(1)-Cr(1)-C(10) C(7)-Cr(1)-C(10) C(8)-Cr(1 )-C(10) C(9)-Cr(1)-C(10) N(1)-Cr(1 )-C(1 0) C(2)-Cr(1)-B(1) C(3)-Cr(1)-B(1) C(1)-Cr(1)-B(1) C(7)-Cr(1)-B(1) C(8)-Cr(1)-B(1) C(9)-Cr(1)-B(1) N(1)-Cr(1)-B(l) C(1O)-Cr(1)-B(1) C(4)-Cr(2)-C(5) C(4)-Cr(2)-C(6) C(5)-Cr(2)-C(6) C(4)-Cr(2)-C(19) C(5)-Cr(2)-C(19) C(6)-Cr(2)-C(19) C(4)-Cr(2)-N(2) C(5)-Cr(2)-N(2) C(6)-Cr(2)-N(2) C(19)-Cr(2)-N(2) C(4)-Cr(2)-C(20) C(5)-Cr(2)-C(20) C(6)-Cr(2)-C(20) C(19)-Cr(2)-C(20) N(2)-Cr(2)-C(20) C(4)-Cr(2)-C(21) C(5)-Cr(2)-C(21 ) C(6)-Cr(2)-C(21 ) C(19)-Cr(2)-C(21) N(2)-Cr(2)-C(21) C(20)-Cr(2)-C(2l) C(4)-Cr(2)-C(22) C(5)-Cr(2)-C(22) C(6)-Cr(2)-C(22) C(19)-Cr(2)-C(22) N(2)-Cr(2)-C(22) C(20)-Cr(2)-C(22) C(2l)-Cr(2)-C(22) C(4)-Cr(2)-B(2) C(5)-Cr(2)-B(2) 67.61(18) 37.31(16) 164.44(18) 101.27(18) 103.12(17) 37.44(14) 67.36(15) 80.61(15) 102.3(2) 169.7(2) 97.51(19) 79.66(18) 66.16(17) 36.19(16) 68.88(15) 138.8(2) 133.9(2) 85.19(19) 67.20(17) 78.85(17) 67.31(18) 37.79(15) 38.42(17) 89.5(2) 88.9(2) 86.7(2) 136.30(19) 134.1(2) 91.3(2) 100.40(17) 166.47(19) 102.57(18) 37.29(14) 160.51(19) 101.1(2) 107.8(2) 36.90(17) 66.88(15) 129.37(19) 86.0(2) 140.9(2) 67.46(18) 80.55(16) 37.00(17) 96.32(18) 100.94(19) 170.7(2) 79.66(18) 69.03(15) 65.78(17) 36.23(16) 83.09(19) 136.4(2) 381 C(6)-Cr(2)-B(2) C(19)-Cr(2)-B(2) N(2)-Cr(2)-B(2) C(20)-Cr(2)-B(2) C(21 )-Cr(2)-B(2) C(22)-Cr(2)-B(2) N(1)-Si(1)-C(1l) N(1)-Si(1)-C(12) C(11)-Si(1)-C(12) N(1)-Si(1)-C(13) C(11)-Si(1)-C(13) C(12)-Si(l)-C(13) N(2)-Si(2)-C(23) N(2)-Si(2)-C(24) C(23)-Si(2)-C(24) N(2)-Si(2)-C(25) C(23)-Si(2)-C(25) C(24)-Si(2)-C(25) C(7)-N(1)-B(1) C(7)-N(l)-Si(1) B(1)-N(1)-Si(1) C(7)-N(1)-Cr(1) B(1)-N(1)-Cr(1) Si(1)-N(l)-Cr(1) C(19)-N(2)-B(2) C(19)-N(2)-Si(2) B(2)-N(2)-Si(2) C(19)-N(2)-Cr(2) B(2)-N(2)-Cr(2) Si(2)-N(2)-Cr(2) N(1)-B(1)-C(10) N(1)-B(1)-C(17) C(1O)-B(1)-C(17) N(1)-B(1)-Cr(1) C(10)-B(1 )-Cr(1) C(17)-B(1 )-Cr(1) N(2)-B(2)-C(22) N(2)-B(2)-C(18) C(22)-B(2)-C(18) N(2)-B(2)-Cr(2) C(22)-B(2)-Cr(2) C(18)-B(2)-Cr(2) O(1)-C(l)-Cr(1) O(2)-C(2)-Cr( 1) O(3)-C(3)-Cr(1) O(4)-C(4)-Cr(2) O(5)-C(5)-Cr(2) O(6)-C(6)-Cr(2) C(8)-C(7)-N(1) C(8)-C(7)-Cr(1 ) N(1 )-C(7)-Cr(1) C(8)-C(7)-H(7A) N(1)-C(7)-H(7A) 135.7(2) 66.87(18) 37.81(15) 77.96(18) 66.98(18) 38.29(17) 108.45(19) 107.5(2) 109.2(2) 107.2(2) 114.0(2) 110.3(2) 109.5(2) 108.4(2) 108.2(2) . 106.4(2) 113.7(2) 110.6(2) 119.3(4) 115.7(3) 124.8(3) 68.5(2) 75.7(2) 130.55(19) 119.1(4) 115.4(3) 125.3(3) 69.2(2) 75.6(2) 129.25(19) 115.0(4) 124.1(4) 120.8(4) 66.5(2) 67.5(3) 136.3(3) 115.9(4) 123.5(4) 120.6(4) 66.6(2) 67.9(3) 137.4(3) 178.6(5) 179.1(5) 177.1(4) 178.9(4) 178.4(5) 176.0(5) 123.0(4) 73.5(3) 74.1(2) 118.2 118.2 382 Cr(1)-C(7)-H(7A) C(7)-C(8)-C(9) C(7)-C(8)-Cr(1 ) C(9)-C(8)-Cr(1 ) C(7)-C(8)-H(8A) C(9)-C(8)-H(8A) Cr(1)-C(8)-H(8A) C(10)-C(9)-C(8) C(1 0)-C(9)-Cr(l) C(8)-C(9)-Cr(l ) C(1 0)-C(9)-H(9A) C(8)-C(9)-H(9A) Cr(1)-C(9)-H(9A) C(9)-C(10)-B(1) C(9)-C(1O)-Cr(1) B(l)-C(10)-Cr(1) C(9)-C(10)-H(1 OA) B(l)-C(10)-H(10A) Cr(1)-C(10)-H(10A) Si(1)-C(1l)-H(11A) Si(1)-C(11)-H(11B) H(11A)-C(1l)-H(11B) Si(1)-C(ll)-H(l1 C) H(11A)-C(ll)-H(l1 C) H(11B)-C(l1)-H(11C) Si(l)-C(l2)-H(12A) Si(l)-C(12)-H(12B) H(12A)-C(l2)-H(12B) Si(1)-C(l2)-H(l2C) H(12A)-C(l2)-H(12C) H(12B)-C(l2)-H(12C) C(16)-C(13)-C(l5) C(16)-C(l3)-C(14) C(15)-C(13)-C(14) C(16)-C(l3)-Si(l ) C(15)-C(l3)-Si(1) C(14)-C(l3)-Si(l) C(13)-C(l4)-H(l4A) C(13)-C(l4)-H(14B) H(l4A)-C(l4)-H(14B) C(13)-C(14)-H(l4C) H(14A)-C(14)-H(l4C) H(14B)-C(l4)-H(14C) C(13)-C(15)-H(15A) C(13)-C(l5)-H(15B) H(15A)-C(15)-H(15B) C(13)-C(15)-H( 15C) H(15A)-C(15)-H(15C) H(15B)-C(15)-H(15C) C(13)-C(l6)-H(l6A) C(13)-C(16)-H(l6B) H(16A)-C(16)-H(l6B) C(13)-C(l6)-H(16C) 118.2 120.6(4) 69.4(3) 72.1(3) 118.9 118.9 118.9 120.3(4) 73.2(3) 70.6(3) 119.4 119.4 119.4 121.2(4) 70.6(3) 74.1(3) 119.0 119.0 119.0 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.2(4) 108.4(4) 108.1(4) 110.8(3) 108.7(3) 111.5(3) 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 383 H(l6A)-C(l6)-H(l6C) H(l6B)-C(l6)-H(l6C) C(l8)-C(l7)-B(l) C(17)-C(18)-B(2) C(20)-C(19)-N(2) C(20)-C(l9)-Cr(2) N(2)-C(19)-Cr(2) C(20)-C(l9)-H(l9A) N(2)-C(l9)-H(l9A) Cr(2)-C(19)-H(l9A) C(19)-C(20)-C(21) C(l9)-C(20)-Cr(2) C(2l)-C(20)-Cr(2) C(19)-C(20)-H(20A) C(21 )-C(20)-H(20A) Cr(2)-C(20)-H(20A) C(22)-C(21 )-C(20) C(22)-C(21 )-Cr(2) C(20)-C(21 )-Cr(2) C(22)-C(21)-H(21A) C(20)-C(2l)-H(21A) Cr(2)-C(21)-H(21A) C(21 )-C(22)-B(2) C(21 )-C(22)-Cr(2) B(2)-C(22)-Cr(2) C(21 )-C(22)-H(22A) B(2)-C(22)-H(22A) Cr(2)-C(22)-H(22A) Si(2)-C(23)-H(23A) Si(2)-C(23)-H(23B) H(23A)-C(23)-H(23B) Si(2)-C(23)-H(23C) H(23A)-C(23)-H(23C) H(23B)-C(23)-H(23C) Si(2)-C(24)-H(24A) Si(2)-C(24)-H(24B) H(24A)-C(24)-H(24B) Si(2)-C(24)-H(24C) H(24A)-C(24)-H(24C) H(24B)-C(24)-H(24C) C(26)-C(25)-C(28) C(26)-C(25)-C(27) C(28)-C(25)-C(27) C(26)-C(25)-Si(2) C(28)-C(25)-Si(2) C(27)-C(25)-Si(2) C(25)-C(26)-H(26A) C(25)-C(26)-H(26B) H(26A)-C(26)-H(26B) C(25)-C(26)-H(26C) H(26A)-C(26)-H(26C) H(26B)-C(26)-H(26C) C(25)-C(27)-H(27A) 109.5 109.5 170.5(5) 170.5(5) 122.6(4) 74.1(3) 73.5(2) 118.4 118.4 118.4 120.9(4) 69.0(3) 71.6(3) 118.5 118.5 118.5 120.2(4) 73.0(3) 71.4(3) 119.6 119.6 119.6 120.5(4) 70.8(3) 73.8(3) 119.4 119.4 119.4 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 109.5 108.7(5) 108.9(4) 108.8(5) 112.6(3) 110.1(4) 107.6(4) 109.5 109.5 109.5 109.5 109.5 109.5 109.5 384 C(25)-C(27)-H(27B) 109.5 H(27A)-C(27)-H(27B) 109.5 C(25)-C(27)-H(27C) 109.5 H(27A)-C(27)-H(27C) 109.5 H(27B)-C(27)-H(27C) 109.5 C(25)-C(28)-H(28A) 109.5 C(25)-C(28)-H(28B) 109.5 H(28A)-C(28)-H(28B) 109.5 C(25)-C(28)-H(28C) 109.5 H(28A)-C(28)-H(28C) 109.5 H(28B)-C(28)-H(28C) 109.5 Symmetry transformations used to generate equivalent atoms: Table 16. Anisotropic displacement parameters (A2x 1()3)for liu50. The anisotropic displacement factor exponent takes the form: _2p2[ h2a*2U ll + ... + 2 h k a* b* Ul2] Cr(1) 28(1) 23(1) 18(1) -2(1) 1(1) 1(1) Cr(2) 25(1) 26(1) 17(1) -2(1) 1(1) 1(1) Si(1) 27(1) 23(1) 23(1) 2(1) 1(1) 6(1) Si(2) 30(1) 23(1) 23(1) 4(1) -2(1) -4(1) 0(1) 80(3) 34(2) 34(2) 7(2) 9(2) -10(2) 0(2) 67(3) 33(2) 45(2) -17(2) 14(2) 3(2) 0(3) 40(3) 62(3) 33(2) -10(2) -5(2) -9(2) 0(4) 37(2) 47(2) 37(2) -2(2) -7(2) 11(2) 0(5) 66(3) 32(2) 33(2) -12(2) 5(2) 3(2) 0(6) 41(3) 72(3) 43(2) 12(2) 21 (2) 7(2) N(l) 23(2) 20(2) 17(2) -1(2) 1(2) -1(2) N(2) 21(2) 26(2) 16(2) 1(2) -3(2) 3(2) B(1) 24(3) 21 (3) 18(3) 0(2) -4(2) -3(2) B(2) 20(3) 25(3) 22(3) -2(2) 2(2) 3(2) C(1) 44(3) 20(3) 27(3) -5(2) -1(3) 1(2) C(2) 36(3) 34(3) 25(3) -5(2) 1(2) -5(3) C(3) 34(3) 33(3) 23(3) -6(2) 3(2) -5(2) C(4) 27(3) 26(3) 23(3) -5(2) 5(2) -2(2) C(5) 34(3) 40(3) 20(3) 2(2) 4(2) 3(3) C(6) 34(3) 38(3) 26(3) 4(2) 2(3) 9(3) C(7) 31(3) 23(3) 17(2) 0(2) -3(2) -2(2) C(8) 29(3) 27(3) 21 (2) -6(2) 5(2) -4(2) C(9) 26(3) 26(3) 27(3) -6(2) 5(2) 0(2) C(1O) 25(3) 27(3) 26(3) -2(2) -2(2) 3(2) C(1l) 22(3) 29(3) 34(3) 1(2) 0(2) 2(2) C(12) 33(3) 46(4) 41(3) 0(3) -7(3) 15(3) C(13) 35(3) 23(3) 33(3) 4(2) 6(3) 5(2) C(l4) 47(4) 24(3) 42(3) -7(2) -1(3) -5(2) C(15) 40(4) 34(3) 68(4) -5(3) 8(3) 15(3) C(16) 52(4) 25(3) 53(4) 12(3) 9(3) 3(3) C(17) 20(3) 20(3) 27(3) 0(2) -2(2) 2(2) C(18) 20(3) 19(3) 25(3) -2(2) 1(2) -1 (2) C(l9) 30(3) 31 (3) 20(2) 4(2) 0(2) 2(2) C(20) 24(3) 43(3) 24(3) -6(2) -3(2) -1(2) C(21) 22(3) 38(3) 34(3) -7(2) -4(2) -4(2) 385 386 C(22) 20(3) 28(3) 28(3) 2(2) 1(2) -5(2) C(23) 28(3) 35(3) 36(3) 0(2) -3(2) -9(2) C(24) 49(4) 46(4) 41(3) 9(3) 6(3) -16(3) C(25) 46(4) 29(3) 33(3) 3(2) -7(3) 8(3) C(26) 56(4) 37(4) 57(4) 0(3) 12(3) 20(3) C(27) 95(6) 27(3) 59(4) -3(3) -3(4) -2(3) C(28) 77(5) 62(5) 55(4) 0(3) -18(4) 32(4) Table 17. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2x 1()3) for liu50. x y z U(eq) H(7A) 7498 640 7151 29 H(8A) 5992 1119 7489 31 H(9A) 4824 1676 6913 32 H(lOA) 5128 1707 5984 31 H(llA) 9132 1172 5666 42 H(llB) 8461 719 5282 42 H(llC) 9592 496 5473 42 H(l2A) 9485 847 6795 60 H(l2B) 9926 146 6664 60 H(l2C) 8964 228 7062 60 H(l4A) 7055 -1051 5540 57 H(l4B) 7545 -430 5261 57 H(l4C) 6600 -354 5671 57 H(l5A) 8810 -1362 5849 71 H(l5B) 9494 -882 6203 71 H(l5C) 9303 -733 5585 71 H(l6A) 7331 -1267 6488 65 H(l6B) 6893 -575 6649 65 H(16C) 8017 -798 6850 65 H(19A) 6557 1582 3058 33 H(20A) 5445 746 2805 36 H(21A) 4987 -82 3417 38 H(22A) 5562 -34 4316 31 H(23A) 8869 1523 4373 49 H(23B) 8079 1751 4828 49 H(23C) 8866 2255 4566 49 H(24A) 8606 1908 3260 68 H(24B) 8558 2656 3403 68 H(24C) 7639 2332 3067 68 H(26A) 5390 2938 4722 75 H(26B) 6254 2458 4950 75 H(26C) 5406 2203 4534 75 H(27A) 6797 3682 4447 91 H(27B) 7688 3449 4045 91 H(27C) 7677 3195 4647 91 H(28A) 5433 3303 3797 97 H(28B) 5478 2585 3572 97 H(28C) 6349 3094 3403 97 Table 18. Torsion angles [0] for liu50. C(lI)-Si(l)-N(l)-C(7) C( 12)-Si( l)-N(l)-C(7) C(13)-Si(I)-N(I)-C(7) C(lI)-Si(l)-N(l)-B(l) C(12)-Si(1)-N(1)-B(1) C(l3)-Si(l)-N(l)-B(l ) C(11)-Si(l)-N(l)-Cr(l) C( 12)-Si(l)-N(l )-Cr(l) C(l3)-Si(l)-N(l )-Cr(l) C(2)-Cr(l)-N(l )-C(7) C(3)-Cr(l)-N(l )-C(7) C(l )-Cr(l)-N(l )-C(7) C(8)-Cr(l)-N(l)-C(7) C(9)-Cr(l)-N(l )-C(7) C(l O)-Cr(l)-N(l )-C(7) B(l)-Cr(l )-N(l)-C(7) C(2)-Cr(1)-N(1)-B(1) C(3)-Cr(1)-N(1)-B(1) C(l)-Cr(l)-N(l )-B(l) C(7)-Cr(l)-N(l )-B(l) C(8)-Cr(l)-N(l )-B(l) C(9)-Cr(l)-N(l )-B(l) C(1O)-Cr(l)-N(l )-B(l) C(2)-Cr(l)-N(l )-Si(l) C(3)-Cr( 1)-N(l)-Si(l) C(l )-Cr(l)-N(l)-Si(l) C(7)-Cr(I)-N(I)-Si(l) C(8)-Cr(l)-N(l)-Si(l) C(9)-Cr(l)-N(l )-Si(l) C(l O)-Cr(l )-N(l)-Si(l) B(1 )-Cr(I)-N(1 )-Si(l) C(23)-Si(2)-N(2)-C(l9) C(24)-Si(2)-N(2)-C(l9) C(25)-Si(2)-N(2)-C(l9) C(23)-Si(2)-N(2)-B(2) C(24)-Si(2)-N(2)-B(2) C(25)-Si(2)-N(2)-B(2) C(23)-Si(2)-N(2)-Cr(2) C(24)-Si(2)-N(2)-Cr(2) C(25)-Si(2)-N(2)-Cr(2) C(4)-Cr(2)-N(2)-C(19) C(5)-Cr(2)-N(2)-C(l9) C(6)-Cr(2)-N(2)-C(l9) C(20)-Cr(2)-N(2)-C(19) C(21 )-Cr(2)-N(2)-C(19) C(22)-Cr(2)-N(2)-C(l9) B(2)-Cr(2)-N(2)-C(19) C(4)-Cr(2)-N(2)-B(2) C(5)-Cr(2)-N(2)-B(2) C(6)-Cr(2)-N(2)-B(2) C(l9)-Cr(2)-N(2)-B(2) C(20)-Cr(2)-N(2)-B(2) -147.3(3) -29.4(4) 89.2(3) 37.0(4) 154.9(4) -86.5(4) -64.5(3) 53.5(3) 172.1(2) -43.3(7) 76.1(3) 166.1(3) -28.8(3) -65.2(3) -100.8(3) -130.1(4) 86.8(7) -153.8(3) -63.8(3) 130.1(4) 101.3(3) 64.9(3) 29.3(3) -149.3(6) -29.9(3) 60.0(3) -106.1(3) -134.8(3) -171.3(3) 153.1(3) 123.9(4) -147.4(3) -29.6(4) 89.3(3) 36.5(4) 154.3(4) -86.7(4) -64.2(3) 53.6(3) 172.5(2) 166.5(3) -57.0(8) 75.2(3) -29.0(3) -65.0(3) -100.7(3) -129.4(4) -64.2(3) 72.4(8) -155.4(3) 129.4(4) 100.4(3) 387 C(2l)-Cr(2)-N(2)-8(2) C(22)-Cr(2)-N(2)-8(2) C(4)-Cr(2)-N(2)-Si(2) C(5)-Cr(2)-N(2)-Si(2) C(6)-Cr(2)-N(2)-Si(2) C(19)-Cr(2)-N(2)-Si(2) C(20)-Cr(2)-N(2)-Si(2) C(2l)-Cr(2)-N(2)-Si(2) C(22)-Cr(2)-N(2)-Si (2) 8(2)-Cr(2)-N(2)-Si(2) C(7)-N(l)-8(l)-C(l0) Si(1)-N(l)-8(l)-C(l 0) Cr(l )-N(1 )-8( 1)-C(1 0) C(7)-N(1)-8(1)-C(17) Si(I)-N(1)-8(1)-C(17) Cr(1 )-N(1)-8(1)-C(17) C(7)-N(I)-8(1 )-Cr(l) Si(1)-N(1)-8(1)-Cr(1 ) C(2)-Cr(1)-8 (1)-N(1) C(3)-Cr(1)-8 (1 )-N(1) C( l)-Cr(1)-8(1 )-N(1) C(7)-Cr(1)-8(1 )-N(1) C(8)-Cr( 1)-8(1 )-N(1) C(9)-Cr(1)-8(1 )-N(1) C(1O)-Cr(1)-8(1 )-N(I) C(2)-Cr( 1)-8(1)-C(10) C(3)-Cr(1)-8(1 )-C(1 0) C(l)-Cr(1)-8(l )-C(1 0) C(7)-Cr(1)-8(1)-C(10) C(8)-Cr(I)-8(1 )-C( 10) C(9)-Cr(1)-8(1)-C( 10) N(l)-Cr(I)-8(1)-C( 10) C(2)-Cr(1)-8(1)-C(17) C(3)-Cr(1)-8 (1 )-C(17) C(1 )-Cr(1)-8 (1 )-C(17) C(7)-Cr(I)-8(1)-C(17) C(8)-Cr(1)-8(1 )-C(17) C(9)-Cr(1)-8(1 )-C(17) N(1)-Cr(1)-8(1)-C(17) C(1O)-Cr(l)-8(l )-C(17) C(19)-N(2)-8(2)-C(22) Si(2)-N(2)-8(2)-C(22) Cr(2)-N(2)-8(2)-C(22) C(19)-N(2)-8(2)-C(18) Si(2)-N(2)-8(2)-C(18) Cr(2)-N(2)-8(2)-C(18) C(19)-N(2)-8(2)-Cr(2) Si(2)-N(2)-8(2)-Cr(2) C(4)-Cr(2)-8(2)-N(2) C(5)-Cr(2)-8(2)-N(2) C(6)-Cr(2)-8(2)-N(2) C(19)-Cr(2)-8(2)-N(2) C(20)-Cr(2)-8(2)-N(2) 64.4(3) 28.7(3) 60.0(3) -163.5(6) -31.2(3) -106.5(3) -135.5(3) -171.5(3) 152.8(3) 124.1(4) 6.3(6) -178.2(3) -48 .4(4) -174.2(4) 1.4(6) 131.1 (5) 54.7(3) -129.8(3) -156.0(3) 37.0(4) 118.7(3) -30.3(2) -67.3(3) -104.5(3) -132.8(4) -23.2(4) 169.8(3) -108.5(3) 102.5(3) 65.5(3) 28.3(3) 132.8(4) 88.5(6) -78.6(6) 3.2(5) -145.8(6) 177.2(5) 140.0(5) -115.5(6) 111.7(6) 7.6(6) -176.4(3) -48.2(4) -171.8(4) 4.2(6) 132.4(5) 55.8(3) -i28.2(3) 116.9(3) -161.1(3) 35.6(4) -30.6(2) -67.7(3) 388 C(21)-Cr(2)-B(2)-N(2) C(22)-Cr(2)-B(2)-N(2) C(4)-Cr(2)-B(2)-C(22) C(5)-Cr(2)-B(2)-C(22) C(6)-Cr(2)-B(2)-C(22) C(19)-Cr(2)-B(2)-C(22) N(2)-Cr(2)-B(2)-C(22) C(20)-Cr(2)-B(2)-C(22) C(21)-Cr(2)-B(2)-C(22) C(4)-Cr(2)-B(2)-C(18) C(5)-Cr(2)-B(2)-C(18) C(6)-Cr(2)-B(2)-C(18) C(19)-Cr(2)-B(2)-C(18) N(2)-Cr(2)-B(2)-C(18) C(20)-Cr(2)-B(2)-C(18) C(21 )-Cr(2)-B(2)-C(18) C(22)-Cr(2)-B(2)-C(18) C(2)-Cr(1)-C(1)-0(1) C(3)-Cr(I)-C(1 )-0(1) C(7)-Cr( I)-C(1)-0(1) C(8)-Cr(1)-C(1)-0(1) C(9)-Cr(I)-C(1)-0(1) N(I)-Cr(I)-C(I)-O(I) C(lO)-Cr(1 )-C(1)-0(1) B(I)-Cr(I)-C(1)-O(1) C(3)-Cr(1)-C(2)-0(2) C(1 )-Cr(I)-C(2)-0(2) C(7)-Cr(1)-C(2)-0(2) C(8)-Cr( 1)-C(2)-0(2) C(9)-Cr(1)-C(2)-0(2) N(1 )-Cr(1)-C(2)-0(2) C(1O)-Cr(1 )-C(2)-0(2) B(1)-Cr(I)-C(2)-0(2) C(2)-Cr(I)-C(3)-0(3) C(I)-Cr(I)-C(3)-0(3) C(7)-Cr(1)-C(3)-0(3) C(8)-Cr(I)-C(3)-0(3) C(9)-Cr(I)-C(3)-0(3) N(I)-Cr(I)-C(3)-0(3) C(10)-Cr(1)-C(3)-0(3) B(I)-Cr(1)-C(3)-0(3) C(5)-Cr(2)-C(4)-0(4) C(6)-Cr(2)-C(4)-0(4) C(19)-Cr(2)-C(4)-0(4) N(2)-Cr(2)-C(4)-0(4) C(20)-Cr(2)-C(4)-0(4) C(21)-Cr(2)-C(4)-0(4) C(22)-Cr(2)-C(4)-O(4) B(2)-Cr(2)-C(4)-0(4) C(4)-Cr(2)-C(5)-0(5) C(6)-Cr(2)-C(5)-0(5) C(19)-Cr(2)-C(5)-0(5) N(2)-Cr(2)-C(5)-0(5) -104.9(3) -133.7(4) -109.4(3) -27.4(4) 169.3(3) 103.1(3) 133.7(4) 66.0(3) 28.8(3) 2.3(5) 84.2(6) -79.0(6) -145.3(6) -114.6(6) 177.7(5) 140.5(6) 111.7(6) 74(20) -12(20) -101(20) -167(19) 158(20) -113(20) 177(100) -147(20) -79(33) -167(100) 9(34) 28(33) 63(33) 42(34) 95(33) 110(33) -25(8) 66(8) -155(8) -122(8) -102(8) 169(8) -175(100) 146(8) 38(25) -48(25) -139(25) -151(25) 162(100) 123(25) 139(25) 175(100) -19(17) 70(17) 159(17) -156(17) 389 ------------- --_.- C(20)-Cr(2)-C(5)-O(5) C(21)-Cr(2)-C(5)-O(5) C(22)-Cr(2)-C(5)-O(5) B(2)-Cr(2)-C(5)-O(5) C(4)-Cr(2)-C(6)-O(6) C(5)-Cr(2)-C(6)-O(6) C(19)-Cr(2)-C(6)-O(6) N(2)-Cr(2)-C(6)-O(6) C(20)-Cr(2)-C(6)-O(6) C(21 )-Cr(2)-C(6)-O(6) C(22)-Cr(2)-C(6)-O(6) B(2)-Cr(2)-C(6)-O(6) B(1)-N (1 )-C(7)-C(8) Si(1 )-N(1)-C(7)-C(8) Cr(1)-N(1 )-C(7)-C(8) B(1)-N(1)-C(7)-Cr(1) Si(1 )-N(1 )-C(7)-Cr(1) C(2)-Cr(1)-C(7)-C(8) C(3)-Cr(1)-C(7)-C(8) C(1)-Cr(1)-C(7)-C(8) C(9)-Cr(1)-C(7)-C(8) N(1 )-Cr(1 )-C(7)-C(8) C(1 O)-Cr(1 )-C(7)-C(8) B(1)-Cr(1 )-C(7)-C(8) C(2)-Cr(1)-C(7)-N(1) C(3)-Cr(1)-C(7)-N(1) C(1 )-Cr(1)-C(7)-N(1) C(8)-Cr(1)-C(7)-N(1) C(9)-Cr(1)-C(7)-N(1) C(1O)-Cr(1 )-C(7)-N(1) B(1)-Cr(1)-C(7)-N(1) N (1 )-C(7)-C(8)-C(9) Cr(1)-C(7)-C(8)-C(9) N(l)-C(7)-C(8)-Cr(1) C(2)-Cr(1)-C(8)-C(7) C(3)-Cr(1)-C(8)-C(7) C(1 )-Cr(1)-C(8)-C(7) C(9)-Cr(1)-C(8)-C(7) N(1)-Cr(1 )-C(8)-C(7) C(1O)-Cr(1)-C(8)-C(7) B(1)-Cr(1)-C(8)-C(7) C(2)-Cr(1)-C(8)-C(9) C(3)-Cr(1)-C(8)-C(9) C(1 )-Cr(1)-C(8)-C(9) C(7)-Cr(1)-C(8)-C(9) N (1 )-Cr(1)-C(8)-C(9) C(1O)-Cr(1)-C(8)-C(9) B(1)-Cr(1)-C(8)-C(9) C(7)-C(8)-C(9)-C(10) Cr(1)-C(8)-C(9)-C(10) C(7)-C(8)-C(9)-Cr(1) C(2)-Cr(1)-C(9)-C(1 0) C(3)-Cr(1)-C(9)-C(10) 178(100) -148(17) -115(17) -98(17) 73(7) -17(7) -151(7) 173(6) -118(6) -97(6) -163(6) 152(6) -0.8(6) -176.8(4) 57.4(4) -58.2(4) 125.9(2) 33.5(4) 119.7(3) -153.5(3) -28.2(3) -132.6(4) -63.9(3) -102.0(3) 166.1(3) -107.8(3) -20.9(4) 132.6(4) 104.3(3) 68.6(2) 30.6(2) -4.8(7) 52.9(4) -57.7(4) -154.9(3) -66.0(3) 87.6(7) 133.8(4) 29.0(2) 105.0(3) 66.8(3) 71.3(3) 160.2(3) -46.2(8) -133.8(4) -104.8(3) -28.8(3) -67.0(3) 4.3(7) 56.0(4) -51.7(4) 118.9(3) -163.2(3) 390 C(l )-Cr(1)-C(9)-C(10) C(7)-Cr(1)-C(9)-C(10) C(8)-Cr(1)-C(9)-C(10) N(l )-Cr(l )-C(9)-C(l 0) B(l )-Cr(l )-C(9)-C( 10) C(2)-Cr(1)-C(9)-C(8) C(3)-Cr(1)-C(9)-C(8) C(l )-Cr( 1)-C(9)-C(8) C(7)-Cr( 1)-C(9)-C(8) N(1 )-Cr(1)-C(9)-C(8) C(1O)-Cr(1)-C(9)-C(8) B(1)-Cr(l )-C(9)-C(8) C(8)-C(9)-C(l O)-B(l) Cr(1)-C(9)-C(l0)-B(1) C(8)-C(9)-C(1O)-Cr(l) N(1)-B(l )-C(l 0)-C(9) C(l7)-B(1)-C(l0)-C(9) Cr(l)-B(1)-C(l0)-C(9) N(l)-B(l)-C(lO)-Cr(l) C(l7)-B(l )-C(l O)-Cr(l) C(2)-Cr(1)-C(l 0)-C(9) C(3)-Cr(1)-C(10)-C(9) C(l )-Cr(1)-C(10)-C(9) C(7)-Cr(l )-C(1 0)-C(9) C(8)-Cr(1)-C(10)-C(9) N(l )-Cr(1)-C(10)-C(9) B(l )-Cr(l )-C(l 0)-C(9) C(2)-Cr( 1)-C( 10)-B(l) C(3)-Cr(l )-C(l 0)-B(l) C( 1)-Cr( 1)-C(l 0)-B(l) C(7)-Cr( 1)-C( 10)-B(l) C(8)-Cr(1 )-C(1 O)-B(l) C(9)-Cr( 1)-C( 10)-B(l) N(l)-Cr(1)-C( 1O)-B(l) N(l )-Si(l )-C(13)-C( 16) C(l1)-Si(l )-C(l3)-C(l6) C(12)-Si(l )-C( 13)-C(16) N(1)-Si(l )-C(l3)-C( 15) C(l1)-Si(l)-C(l3)-C(l5) C(12)-Si(l)-C( 13)-C(15) N(l )-Si(l)-C(l3)-C(14) C(11)-Si(1)-C(l3)-C(l4) C(l2)-Si(1)-C(l3)-C(14) N(l)-B(l)-C(l7)-C(l8) C(1O)-B(l)-C(l7)-C(l8) Cr(l)-B(l)-C(l7)-C(l8) B(1)-C(l7)-C(l8)-B(2) N(2)-B(2)-C(l8)-C(17) C(22)-B(2)-C(l8)-C(17) Cr(2)-B(2)-C(l8)-C(17) B(2)-N(2)-C(l9)-C(20) Si(2)-N(2)-C(19)-C(20) Cr(2)-N(2)-C(19)-C(20) 32.4(4) -103.5(3) -131.6(4) -66.9(3) -29.9(3) -109.5(3) -31.6(4) 164.1(3) 28.1 (3) 64.7(3) 131.6(4) 101.7(3) 1.6(7) 56.4(4) -54.7(4) -6.8(7) 173.7(4) -54.7(4) 48.0(3) -131.6(4) -63.2(3) 86.4(l1) -155.4(3) 66.0(3) 29.7(3) 103.4(3) 132.2(4) 164.6(3) -45.8(11) 72.4(3) -66.2(3) -102.5(3) -132.2(4) -28.8(2) -59.0(4) -179.0(3) 57.8(4) -179.0(3) 61.0(4) -62.2(4) 61.9(4) -58.1(4) 178.7(3) 160(3) -20(3) -109(3) -44(5) 153(3) -26(3) -116(3) -1.0(7) -177.3(4) 58.0(4) 391 B(2)-N(2)-C(19)-Cr(2) Si(2)-N (2)-C(l9)-Cr(2) C(4)-Cr(2)-C(19)-C(20) C(5)-Cr(2)-C(19)-C(20) C(6)-Cr(2)-C(19)-C(20) N (2)-Cr(2)-C(19)-C(20) C(21)-Cr(2)-C(l9)-C(20) C(22)-Cr(2)-C(l9)-C(20) B (2)-Cr(2)-C(19)-C(20) C(4)-Cr(2)-C(19)-N(2) C(5)-Cr(2)-C(19)-N (2) C(6)-Cr(2)-C(l9)-N(2) C(20)-Cr(2)-C( 19)-N(2) C(21 )-Cr(2)-C(l9)-N(2) C(22)-Cr(2)-C( 19)-N(2) B(2)-Cr(2)-C(19)-N(2) N(2)-C( 19)-C(20)-C(21) Cr(2)-C(19)-C(20)-C(21) N(2)-C(19)-C(20)-Cr(2) C(4)-Cr(2)-C(20)-C( 19) C(5)-Cr(2)-C(20)-C(19) C(6)-Cr(2)-C(20)-C(19) N (2)-Cr(2)-C(20)-C( 19) C(2l)-Cr(2)-C(20)-C(l9) C(22)-Cr(2)-C(20)-C(19) B(2)-Cr(2)-C(20)-C(19) C(4)-Cr(2)-C(20)-C(21) C(5)-Cr(2)-C(20)-C(21 ) C(6)-Cr(2)-C(20)-C(21) C( 19)-Cr(2)-C(20)-C(21) N(2)-Cr(2)-C(20)-C(21) C(22)-Cr(2)-C(20)-C(21 ) B(2)-Cr(2)-C(20)-C(21 ) C(19)-C(20)-C(21 )-C(22) Cr(2)-C(20)-C(21 )-C(22) C( 19)-C(20)-C(21)-Cr(2) C(4)-Cr(2)-C(21 )-C(22) C(5)-Cr(2)-C(21 )-C(22) C(6)-Cr(2)-C(21 )-C(22) C(19)-Cr(2)-C(21)-C(22) N(2)-Cr(2)-C(21)-C(22) C(20)-Cr(2)-C(21 )-C(22) B(2)-Cr(2)-C(21)-C(22) C(4)-Cr(2)-C(21 )-C(20) C(5)-Cr(2)-C(21 )-C(20) C(6)-Cr(2)-C(21)-C(20) C( 19)-Cr(2)-C(21)-C(20) N(2)-Cr(2)-C(21 )-C(20) C(22)-Cr(2)-C(21 )-C(20) B(2)-Cr(2)-C(21)-C(20) C(20)-C(21 )-C(22)-B(2) Cr(2)-C(21 )-C(22)-B(2) C(20)-C(21 )-C(22)-Cr(2) -59.0(4) 124.7(2) -151.5(3) 32.1(4) 118.7(3) -132.0(4) -27.5(3) -63.2(3) -101.0(3) -19.5(4) 164.1(3) -109.3(3) 132.0(4) 104.6(3) 68.9(3) 31.0(2) -6.3(7) 51.5(4) -57.8(4) 81.1(7) -157.1(3) -67.1(3) 29.3(3) 135.0(4) 105.7(3) 67.4(3) -53.8(7) 67.9(3) 158.0(3) -135.0(4) -105.7(3) -29.2(3) -67.6(3) 6.1 (7) 56.4(4) -50.3(4) 28.5(4) 114.6(3) -165.6(3) -103.7(3) -67.3(3) -131.1(4) -30.3(3) 159.6(3) -114.3(3) -34.5(5) 27.4(3) 63.9(3) 131.1(4) 100.8(3) 1.1(7) 56.7(4) -55.6(4) 392 393 N(2)- R(2)-('(22)-('(21) C( 18)-R(2)-C(22)-C(21) Cr(2)-13(2)-C(22)-('(21) N(2)-B(2)-C(22)-Cr(2) C( 18)-1:3(2)-C(22)-Cr(2) C(4)-Cr(2)-(,(22)-C(21) C(5)-Cr(2)-C(22)-C(21) (,(6)-Cr(2)-C(22)-(:(21) C( 19)-CI'(2)-('(22)-C(2 I ) N(2)-('r(2)-C(22)-C(21) C(20)-Cr(2)-C(22)-(,(21) 1:3(2)-Cr(2)-C(22)-C(21) C(...J.)-('r(2)-C(22)-13(2) ('(.'i )-Cr(2)-('(22 )-1:3(2) C(6)-( :1'(2)-('(22)- B(2) C( 19)-Cr(2)-C(22)- 8(2) N(2)-('r(2)-C(22)-13(2) ( '(20)-('r(2)-C(22)-B(2) ('(21 )-('1'(2)-('(22)- H(2) N(2)-S i(2)-('(25)-('(26) ('(23 )-Si(2)-C(25 )-C(26) (,(24)-Si(2)-C(25)-( :(26) N(2)-Si(2)-C(25)-C'(28) C(23 )-Si(2)-('(25 )-('(28) ('(24)-S i(2)-e(25 )-( '(28) 1\1 (2)-S i(2)-C(25)-('(27) ('(23 )-Si(2)-C(25 )-(:(27) ('(24)-Si(2)-C(25 )-('(27) Symmetry lmnsformalion" lIsed 10 generate equi,·alcnt alOI11": -7.8(7) 171.7(4) -55.3(-+) ...J.7.6(...J.) -133.0(-+) -158.2(3) -675(3) 77.5( 13) 65.8(3) 103.0(3) 29.8(3) 1l1.4(4) 70.4(3) 161.1(3) -53.9( 13) -65.6(3) -28.3(3) -101.6(3) -1l1 ....J.(4) 53.0(-+) -67.6(4) 1705(4) -685(4) 170.9(-+) -1,g.9(5) In.O(3) 52'-+(4) -69.5(-+) Figm'~ 4. ORTEP i!!lJstrflt!O!l of2, with thermal e!!ipsoids di"?\.'.'n at the 35% probability !eve!. 394 X-ray Crystal Structure Determination. Crystals of2 suitable for X-ray diffraction were obtained by evaporation of a solution of2 in EtzO. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2• All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Broker XRD, Madison, WI). Crystallographic data and some details ofdata collection and crystal structure refinement for C lOH lOB2N2 are given in the following tables. Table 19. Crystal data and structure refmement for 2 (liu60). Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient liu60 CIO HIO Bz Nz 179.82 173(2) K 0.71073 A Orthorhombic Pbcn a =19.076(6) A b =9.301(3) A c =10.997(3) A 1951.1(10) A3 8 1.224 Mg/m3 0.071 mm-1 a= 90°. ---------- .. - P(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 27.000 Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters Goodness-of-fit on p2 Pinal R indices [I>2sigma(I)] R indices (all data) Largest diff. peak and hole 752 0.34 x 0.16 x 0.12 mm3 2.14 to 27.000 • -24<=h<=24, -l1<=k<=l1 , -13<=k=12 9364 2125 [ROnt) = 0.0438] 99.6% Semi-empirical from equivalents 0.9915 and 0.9762 Pull-matrix least-squares on p2 2125/0/167 1.034 Rl = 0.0463, wR2 = 0.1012 Rl = 0.0743, wR2 = 0.1157 0.170 and -0.151 e.A-3 395 Table 20. Atomic coordinates ( x 1()4) and equivalent isotropic displacement parameters (A2x 103) for liu60. U(eg) is defined as one third of the trace of the orthogonalized Uij tensor. N(1) N(2) B(1) B(2) C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) x 3774(1) 5752(1) 3698(1) 5190(1) 3358(1) 2829(1) 2697(1) 3096(1) 4221(1) 4645(1) 5196(1) 5707(1) 6235(1) 6253(1) y 901(2) -3060(2) 407(2) -2612(2) 1931(2) 2524(2) 2082(2) 1060(2) -706(2) -1550(2) -3249(2) -4201(2) -4587(2) -4018(2) z 1950(1) 3802(1) 3169(2) 4578(2) 1452(2) 2098(2) 3305(2) 3855(2) 3669(1) 4070(1) 5831(2) 6136(2) 5302(2) 4164(2) U(eq) 35(1) 36(1) 31(1) 31(1) 40(1) 41(1) 41(1) 37(1) 34(1) 34(1) 35(1) 39(1) 41(1) 40(1) Table 21. N(1)-C(l) N(l)-B(1) N(2)-C(1O) N(2)-B(2) B(1)-C(4) B(1)-C(5) Bond lengths [A] and angles [0] for liu60. 1.359(2) 1.425(2) 1.367(2) 1.431(2) 1.502(3) 1.539(3) B(2)-C(7) B(2)-C(6) C(1)-C(2) C(2)-C(3) C(3)-C(4) C(5)-C(6) C(7)-C(8) C(8)-C(9) C(9)-C(1O) 1.500(2) 1.539(2) 1.352(3) 1.413(3) 1.360(2) 1.210(2) 1.359(2) 1.410(3) 1.359(3) 396 C(1)-N(1)-B(1) 123.22(16) C(10)-N(2)-B(2) 122.66(15) N(1)-B(1)-C(4) 114.79(15) N(1)-B(1)-C(5) 119.16(15) C(4)-B(1)-C(5) 126.04(15) N(2)-B(2)-C(7) 115.34(16) N(2)-B(2)-C(6) 118.39(15) C(7)-B(2)-C(6) 126.27(16) C(2)-C(1)-N(1) 120.72(17) C(1)-C(2)-C(3) 120.60(17) C(4)-C(3)-C(2) 121.37(17) C(3)-C(4)-B(1) 119.24(16) C(6)-C(5)-B(1) 178.17(18) C(5)-C(6)-B(2) 179.45(18) C(8)-C(7)-B(2) 119.27(17) C(7)-C(8)-C(9) 121.25(17) C(1O)-C(9)-C(8) 121.18(17) C(9)-C(10)-N(2) 120.30(17) Symmetry transformations used to generate equivalent atoms: Table 22. Anisotropic displacement parameters (A2x 1()3)for liu60. The anisotropic displacement factor exponent takes the form: _2Jt2[ h2a*2Ull + ... + 2 h k a* b* U12 ] Ull U22 U33 U23 UB U12 N(1) 38(1) 39(1) 28(1) 0(1) 4(1) 3(1) N(2) 41(1) 37(1) 30(1) 0(1) 2(1) -1(1) B(1) 34(1) 31(1) 28(1) 0(1) 0(1) -5(1) B(2) 36(1) 29(1) 30(1) -2(1) -2(1) -2(1) C(1) 45(1) 46(1) 29(1) 7(1) -4(1) 1(1) C(2) 38(1) 40(1) 45(1) 8(1) -6(1) 3(1) C(3) 34(1) 42(1) 47(1) 1(1) 7(1) 4(1) C(4) 40(1) 39(1) 32(1) 3(1) 6(1) -2(1) C(5) 40(1) 36(1) 26(1) -1(1) 4(1) -1(1) C(6) 43(1) 35(1) 24(1) -2(1) 2(1) 0(1) C(7) 39(1) 36(1) 29(1) -1(1) 1(1) 1(1) C(8) 46(1) 38(1) 34(1) 3(1) -8(1) -1(1) C(9) 35(1) 36(1) 53(1) -2(1) -12(1) 5(1) C(10) 34(1) 38(1) 46(1) -7(1) 2(1) 0(1) Table 23. Hydrogen coordinates ( x 104) and isotropic displacement parameters (A2x 103) for liu60. x y z U(eq) H(1N) H(2N) H(1) H(2) H(3) H(4) H(7) H(8) H(9) H(10) 4117(10) 5797(10) 3465(9) 2539(10) 2307(10) 2994(10) 4856(10) 5720(10) 6606(9) 6624(9) 596(19) -2700(20) 2187(19) 3290(20) 2560(19) 819(18) -3024(19) -4656(19) -5242(19) -4290(18) 1497(17) 2985(19) 586(18) 1738(17) 3723(17) 4694(17) 6422(18) 6964(17) 5534(15) 3529(17) 42(5) 56(6) 53(5) 54(5) 46(5) 48(5) 50(5) 51(5) 42(5) 49(5) 397 Table 24. Torsion angles [0] for liu60. C(1)-N(1)-B(1)-C(4) C(1)-N(1)-B(1)-C(5) C(10)-N(2)-B(2)-C(7) C(10)-N(2)-B(2)-C(6) B(1 )-N(1)-C(1)-C(2) N(1 )-C( 1)-C(2)-C(3) C(1)-C(2)-C(3)-C(4) C(2)-C(3)-C(4)-B(1) N(1)-B(1)-C(4)-C(3) C(5)-B(1)-C(4)-C(3) N(1)-B(1)-C(5)-C(6) C(4)-B(1)-C(5)-C(6) B(1)-C(5)-C(6)-B(2) N(2)-B(2)-C(6)-C(5) C(7)-B(2)-C(6)-C(5) N(2)-B(2)-C(7)-C(8) C(6)-B(2)-C(7)-C(8) B(2)-C(7)-C(8)-C(9) C(7)-C(8)-C(9)-C(10) C(8)-C(9)-C(10)-N(2) B(2)-N(2)-C(10)-C(9) Symmetry transformations used to generate equivalent atoms: 2.9(2) -176.74(15) 1.0(2) -178.84(15) -1.6(3) -0.2(3) 0.5(3) 1.0(3) -2.6(2) 177.05(16) 83(5) -96(5) -18(22) -64(19) 116(19) -1.3(2) 178.56(15) 0.7(3) 0.2(3) -0.5(3) -0.1(3) 398 Additional photophysical data for 1 and 2. -THF 500480 MeCN -OMSO -CH2CI2 460440360340 380 400 420 Wavelength (nm) Figure 5. NonnCllized emission spectra of I ill various solvents. 320 o 300 ;; OJ .!:! .. E (; z >- .~ <:: ~ <:: 33Gouv240 0.3 -THF (299 nm) -CH2CI2 (298 nm) -MeCN (298 nm) 0.2 OMSO (302 nm) -C6H12 (297 nm) ~ <:: 0 'l" 0. ~ .0 « 0.1 Wavelength (nm) Figure 6. Absorption spectra of I ill various solvents (10'<; M in each solvent). The trace for DMSO (orange) is cut off at 255 nm for clarity. 399 04 -THF (300 nm) -CH2CI2 (301 nm) 03 -MeCN (300 nm) DMSO (301 nm) I -C6H12 (298 nm)~ Ic0 0'1~a-DVI .D c:( 0.1 O. 240 270 300 330 Wavelength (nm) Figure 7. Absorption spectra of 2 in various solvents (I O-~ M in each solvent). The trace for DMSO (orange) is cut offal 255 nl11 for clarit)'. C.2.3. Supplemental il1fol'matiol1 for Chapter IV, section 4.4 Synthesis of compound 13. A soJution of J,2-azaborine 3 (2.0 g, 8.79 mmoJ in 60 mL Cl-bCb) was cooled to -20°C, to which a solution of Br2 (0.48 mL, 9.31 mmol in 60 mL CI-bCb) was added dropwise. The reaction was allowed to warm to It and was stirred for 30 min. Solvent was removed under reduced pressure and 30 mL pentane was added. Solids were tiltered through an Acrodisc, and the remaining solvent was removed under reduced pressure. Vacuum distillation (62-65 0c, J20 tnT) provided brominated 13 as a clear, colorless liquid (1.63 g, 6] %). !H NMR (300 MHz, CH2CI2): () 7.87 (d. ~JHH = 7.0 Hz, ]H), 7.27 (d, 3./1111 = 6.7 Hz, ]H), 6.22 (app t, 3./H11 = 6.7 Hz, 1H), 0.94 (s, 9H). 0.54 (s. 6H). DC NMR (75.4 MHz, CD2Cb): () ]47.0, 139.0. 1]] .8,26.9,19.7, -] .3. liB NMR (192.5 MHz. CD2Cb): () 37.4. 400 FTIR (thin film) 3098, 2931, 2860, 2280, 1685, 1601, 1495, 1471, 1441, 1393, 1364, 1336,1264,1210,1192,1126,1090,999,938,823,764,714, 657, 577, 499, 443 em-I. HRMS (EI) calcd for CIOHI8BNSiC181Br(M+) 307.01530, found 307.01500. Compound 14. A solution ofphenylethynylmagnesium bromide (1M in THF; 2.88 mL, 2.88 mmol) was added to a solution of 13 (0.800 g, 2.61 mmol in 10 mL THF) at rt, and was stirred for 16 h. Solvents were removed and column chromatography was performed (EtzO/pentane), which gave compound 14 as a white, crystalline solid (0.738 g, 76%). IHNMR (300 MHz, CH2Ch): &7.95 (d, 3JHH = 7.3 Hz, lH), 7.60 (m, 2H), 7.37 (m, 4H), 6.31 (app t, 3JHH = 7.0 Hz, IH), 1.00 (s, 9H), 0.67 (s, 6H). B C NMR (125.8 MHz, CD2Ch): & 145.3, 138.8, 132.2, 132.0, 129.3, 129.0, 124.3, 112.5, 110.8,97 (br), 27.0, 19.7, -1.8. liB NMR (192.5 MHz, CD2Ch): &28.5. FTIR (thin film) 2953, 2927, 2881,2856,2182,1595,1490,1470,1441,1341,1354, 1273, 1254, 1181, 1132, 1000, 845,757,678 em-I. HRMS (EI) calcd for ClsH23BNSi8IBr(M+) 371.08762, found 371.08818. Compound 15. Method A in Chapter 4, Scheme 4: A flask was charged with CuI (0.005 g, 0.027 mmol), Pd(Cl)2(PPh3)2 (0.009 g, 0.0134 mmol), phenylacetylene (0.069 g, 0.672 mmol), 1,2-azaborine 14 (0.050 g, 0.134 mmo1), NEt3 (0.1 mL), and THF (3 mL). The reaction was stirred at rt for 24 h, whereupon solvents were removed under reduced oressure and the crude mixture was redissolved in CD"Ck IH NMR analysis ... - ... 01 - - indicated diyne 15 was formed in a 1:3 ratio relative to unreacted bromide 14. Method B in Chapter 4, Scheme 4: A vial was charged with CuI (0.008 g, 0.04 401 mmol), Pd(Cl)2(PhCN)2 (0.015 g, 0.04 mmol), P(tBu)3 (0.016 g, 0.08 mmol), phenylacetylene (0.178 g, 1.74 mmol), 1,2-azaborine 14 (0.500 g, 1.34 mmol), NEt3 (0.5 mL), and THF (10 mL). The reaction was stirred at rt for 24 h, whereupon solvents were removed under reduced pressure and the crude mixture was redissolved in CH2Ch. The solution was passed through a dry plug of silica and flushed with CH2Ch. The solvent was removed under reduced pressure and column chromatography was performed (Et20/pentane), which provided 15 as a viscous, brown oil (0.450 g, 85%). IH NMR (300 MHz, CH2Ch): () 7.83 (d, 3JHH = 6.7 Hz, IH), 7.3-7.6 (m, I1H), 6.46 (app t, 3JHH = 7.1 Hz, IH), 1.00 (s, 9H), 0.67 (s, 6H). BC NMR (125.8 MHz, CD2Ch): () 146.8,139.9,132.0,131.9,129.1,129.0,128.8,128.0, 125.3, 124.5, 112.6, 110.4,106.5,93.9,26.9, 19.6, -1.8. llB NMR (192.5 MHz, CD2Ch): () 30.0. FTIR (thin film)3061,2955,2928,2897,2858,2179, 1597, 1585, 1513, 1489, 1470, 1442, 1342, 1251,1185, 1148,1078,1043,844,812,756,690cm-l . Compound 16. A vial was charged with diyne 15 (0.238 g, 0.605 mmol), (MeCN)3Cr(CO)3 (0.282 g, 1.09 mmol), and THF (5 mL), and was stirred at rt for 16 h. Solvents were removed and column chromatography (Et20/pentane) was performed, which gave complex 16 as a red, crystalline solid (0.138 g, 43%). IH NMR (300 MHz, CH2Ch): () 7.3-7.6 (m, IOH), 6.30 (d, 3JHH = 6.5 Hz, IH), 6.05 (d, 3JHH = 4.4 Hz, IH), 5.27 (app t, 3JHH = 6.2 Hz, IH), 1.02 (s, 9H), 0.78 (s, 3H), 0.46 (s, 3H). llB NMR (96.3 MHz, CD2Ch): () 14.9. Compound 12. A solution of complex 16 (0.212 g, 0.40 mmol in 4 mL THF) was cooled to -20 DC, to which was added a solution ofHF-pyridine (0.5 Min THF; 0.88 mL, 402 0.44 mmol). The reaction was allowed to warm to rt and was stirred for 1 h. Solvents were removed and the crude mixture was redissolved in MeCN (5 mL). The solution was stirred at rt for 12 h, whereupon approximately one-half of the solvent was removed under reduced pressure. The remaining solution was passed through a dry plug of silica gel and flushed with EtzO. Solvents were removed and column chromatography was performed (EtzO/pentane), which provided diyne 12 as a ~ight brown oil, which crystallized when stored at -20°C (0.021 g, 19% from complex 16). IH NMR (300 MHz, CHzClz): 68.58 (br, IH), 7.89 (d, 3JHH =7.1 Hz, IH), 7.3-7.6 (m, I1H), 6.47 (app t, 3JHH = 7.0 Hz, IH). BC NMR (125.8 MHz, CDzClz): 6 147.6, 135.2, 132.6, 131.9, 129.3, 129.0, 128.9, 128.2, 111.8. liB NMR (192.5 MHz, CDzClz): 626.9. FTIR (thin film) 3366,3079, 3018, 2927, 2179, 1599, 1535, 1489, 1442, 1301, 1228, 1028,912, 753, 685 em-I. HRMS (EI) calcd for CzoH I4BN (M+) 279.12193, found 279.12247. Compound 20. A solution of ethylmagnesium bromide (1.0 M in THF; 0.98 mL, 0.98 mmol) was added to a solution of 4-(dibutylamino)phenylacetylene (0.225 g, 0.98 mmol in 5 mL THF) at rt. Gas evolution was observed, which ceased after approximately 30 min. The reaction was stirred an additional 2 h, and this solution was then added dropwise to a stirring solution of 13 (0.300 g, 0.98 mmol in 5 mL THF) at rt. Solvent was removed and column chromatography was performed (CHzClzlEtzO/pentane), which gave alkyne 20 as a yellow oil (0.318 g, 65%). IH NMR (300 MHz, CHzClz): 67.86 (d, 3JHH = 7.3 Hz, IH), 7.39 (d, 3JHH = 4.0 Hz, 2H), 7.31 (app t, 3JHH = 9.1 Hz, IH), 6.60 (d, 3J HH = 5.0 Hz, 2H), 6.22 (app t, 3JHH = 403 6.7 Hz, 1H), 3.30 (t, 3JHH = 7.6 Hz, 4H), 1.60 (m, 4H), 1.39 (m, 4H), 0.98 (m, 15H), 0.64 (s,6H). l3C NMR (125.8 MHz, CD2Cb): () 149.0, 144.8, 138.6, 133.8, 133.5, 113.1, 111.8, 109.5,94 (br), 85.5, 74.9, 51.2, 29.9, 27.0, 20.9, 19.7, 14.4, -1.7. lIB NMR (192.5 MHz, CD2Cb): () 28.0. FTIR (thin film) 3308, 3093, 2956, 2930, 2859, 2166, 1606, 1518, 1490,1469,1343,1288,1260,1222,1172,1130, 1109, 104~ 1001,926,844,812,788, 763, 680 cm-I. Compound 21. A vial was charged with CuI (0.013 g, 0.07 mmol), Pd(C1)2(PhCN)2 (0.027 g, 0.07 mmol), P(tBu)3 (0.028 g, 0.014 mmol), 4- cyanophenylacetylene (0.194 g, 1.53 mmol), 1,2-azaborine 20 (0.695 g, 1.39 mmol), NEt3 (0.5 mL), and THF (5 mL). The reaction was stirred at rt for 48 h, whereupon solvents were removed under reduced pressure and the crude mixture was redissolved in CH2Cb. The solution was passed through a dry plug of silica and flushed with CH2Cb. The solvent was removed under reduced pressure and column chromatography (Et20/pentane) was performed, which provided 21 as a an orange-red, crystalline solid (0.454 g, 60%). IH NMR (300 MHz, CH2Cb): () 7.82 (d, 3JHH = 7.1 Hz, 1H), 7.59 (s, 4H), 7.41 (d, 3JHH = 6.5 Hz, IH), 7.33 (d, 3JHH = 7.0 Hz, 2H), 6.60 (d, 3JHH = 7.0 Hz, 2H), 6.40 (app t, 3JHH = 6.7 Hz, 1H), 3.30 (t, 3JHH = 7.6 Hz, 4H), 1.60 (m, 4H), 1.39 (m, 4H), 0.98 (m, 15H), 0.66 (s, 6H). l3C NMR (125.8 MHz, CD2Cb): () 149.0, 147.3, 140.9, 133.4, 132.6, 132.3, 130.5,119.4, 112.9, 112.0, 111.7, 110.9, 109.5,99.4,94 (br), 92.3, 51.2, 29.9, 27.0" 20.9, 19.6, 14.3, -1.8. lIB NMR (192.5 MHz, CD2Cb): () 29.7. FTIR (thin film) 3068, 3042, 2956,2930,2859,2225,2204,2171,1605,1587,1517, 1495, 1469, 1444,1343,1288, 1251,1288,1251,1222,1175,1145,1110,1079, 1042, 1004,927,881,842,812,789, 404 730,691 em-I. Compound 17. A solution ofTBAF (0.1 Min THF; 0.5 mL, 0.05 mmol) was added to a stirred solution of diyne 21 (0.025 g, 0.046 mmol in 3 mL THF) at ct. The reaction was stirred for 20 min., whereupon the solution was passed through a dry silica plug and flushed with THF. The solvent was removed, and column chromatography was performed (Et20/pentane), which provided 17 as a yellow solid (0.008 g, 40%). IH NMR (300 MHz, CH2Ch): b 8.50 (br, 1H), 7.88 (d, 3JHH = 7.0 Hz, 1H), 7.62 (s, 4H), 7.36 (m, 3H), 6.58 (d, 3JHH = 7.0 Hz, 2H), 6.40 (app t, 3JHH = 7.0 Hz, 1H), 3.30 (t, 3JHH = 7.6 Hz, 4H), 1.60 (m, 4H), 1.39 (m, 4H), 0.98 (t, 3JHH = 7.3 Hz, 6H). llB NMR (96.3 MHz, CD2Ch): b 27.3. Compound 23. A solution of ethylmagnesium bromide (1.0 M in THF; 0.98 mL, 0.98 mmol) was added to a solution of 4-cyanophenylacetylene (0.125 g, 0.98 mmo1 in 5 mL THF) at ct. Gas evolution was observed, which ceased after approximately 30 min. The reaction was stirred an additional 1 h, and this solution was then added dropwise to a stirring solution of 13 (0.300 g, 0.98 mmol in 10 mL THF) at ct. Solvent was removed and column chromatography was performed (CH2Ch/Et20/pentane), which gave alkyne 23 as a yellow solid (0.268 g, 69%). IH NMR (300 MHz, CH2Ch): b 7.92 (d, 3JHH = 7.3 Hz, 1H), 7.62 (s, 4H), 7.37 (d, 3JHH = 6.2 Hz, 1H), 6.33 (app t, 3JHH = 7.3 Hz, 1H), 0.96 (s, 9H), 0.62 (s, 6H). B C NMR (125.8 MHz, CD2Ch): b 145.6, 138.9, 133.2, 132.7, 132.5, 128.8, 119.0, 113, 112.5, 108.5,81.8,26.8, 19.6, -1.9. llB NMR (192.5 MHz, CD2Ch): b 27.6. FTIR (thin film) 3237,2954,2932,2886,2859,2224,2188,1598,1490, 1471, 1445, 1404, 1344, 1266, 405 1257, 1173, 1133, 1102, 1036, 1003,936,826,812, 767, 716, 680, 644 em-I. Compound 25. A vial was charged with CuI (0.009 g, 0.049 mmol), Pd(Cl)2(PhCN)2 (0.019 g, 0.049 mmol), PCBu)3 (0.020 g, 0.100 mmol), 4- (dibutylamino)phenylacetylene (0.146 g, 0.64 mmol), 1,2-azaborine 13 (0.150 g, 0.49 mmol), NEt3 (0.5 mL), and THF (5 mL). The reaction was stirred at rt for 16 h, whereupon solvents were removed. Pentane (8 mL) was added, and solids were filtered through an Acrodisc. Compound 25 was not purified further. IH NMR (300 MHz, CH2Ch): {} 7.65 (app t, 3JHH = 7.0 Hz, IH), 7.1 (m, 3H), 6.58 (d,3J HH = 7.0 Hz, 2H), 6.37 (app t, 3J HH = 6.7 Hz, IH), 3.25 (t, 3J HH = 7.6 Hz, 4H), 1.5 (m, 8H), 0.98 (m, 15H), 0.58 (s, 6H). lIB NMR (96.3 MHz, CD2Ch): {} 38.2. Compound 24. A solution of ethylmagnesium bromide (1.0 M in THF; 0.63 mL, 0.63 mmol) was added to a stirred solution of 4-cyanophenylacetylene (0.081 g,0.63 mmol). The solution was stirred for 1 hat rt and was then added to a solution of 25 (assumed 0.49 mmol from previous step) in THF (6 mL). The reaction was stirred at 2 h, whereupon solvents were removed and column chromatography (Et20/pentane) was performed, which gave 24 as an orange-red solid (0.117 g, 44%). IH NMR (300 MHz, CH2Ch): {} 7.78 (d, 3JHH = 7.0 Hz, IH), 7.62 (s, 4H), 7.38 (d, 3JHH = 6.7 Hz, IH), 7.23 (d, 3JHH = 7.0 Hz, 2H), 6.55 (d, 3JHH = 7.0 Hz, 2B), 6.49 (app t, 3JHH = 6.7 Hz, lB), 3.25 (t, 3JHH = 7.6 Hz, 4H), 1.57 (m, 4H), 1.39 (m, 4H), 0.98 (m, 15H), 0.62 (s, 6H). B C NMR (75.4 MHz, CD2Ch): {} 148.2, 145.6, 138.8, 133.0, 132.7, 132.5, 119.1, 113.1, 112.1, 111.7, 110.4, 108.2,95.8,90.0,51.1,29.9,26.8,20.8, 19.6, 14.3,- 1.9. lIB NMR (96.3 MHz, CD2Ch): {} 30.9. FTIR (thin film) 2956, 2930, 2859, 2227, 406 2178,1605,1586,1520,1507,1469,1443,1343,1251, 1221, 1146, 1078, 1043, 1004, 927, 842, 812, 789, 746, 692, 556, 529 cm-I. HRMS (El) calcd for C3sH44BN3Si(M+) 545.33976, found 545.33853. Compound 24 from 23. Method A: A vial was charged with CuI (0.010 g, 0.050 mmol), Pd(CI)z(PhCN)2 (0.020 g, 0.050 mmol), P(tBU)3 (0.022 g, 0.108 mmol), 4- (dibutylamino)phenylacetylene (0.150 g, 0.655 mmo1), 1,2-azaborine 13 (0.150 g, 0.49 mmo1), NEt3 (0.5 mL), and THF (5 mL). The reaction was stirred at rt for 48 h, and then heated to 60°C for 24 h. Solvents were then removed, whereupon IH NMR analysis indicated 24 was formed in a 40:60 ratio with unreacted 23. Compounds 23 and 24 were inseparable by column chromatography. Method B: A solution of4-(dibutylamino)phenylacetylene (0.127 g, 0.55 mmol in 3 mL) was cooled to -78°C, to which was added a solution ofn-BuLi (1.6 M in hexanes; 0.35 mL, 0.55 mmol). The lithiate solution was then added to a solution ofZnCh (l.0 M in EhO; 0.55 mL, 0.55 mmol) at -78°C, which was allowed to warm to rt. The zincate solution was added to a flask containing 23 (0.200 g, 0.50 mmol), Pd(PPh3)4 (0.058 g, 0.050 mmol), and THF (l mL) at rt. The reaction was heated to 80°C for 48 h, whereupon solvents were removed, after which column chromatography (EhO/pentane) provided 24 (0.060 g, 22%). Compound 18. A vial was charged with diyne 24 (0.064 g, 0.117 mmol), (MeCN)3Cr(CO)3 (0.152 g, 0.587 mmo1), and THF (12 mL), and was stirred at rt for 16 h. The reaction was cooled to -20°C, whereupon a solution ofHF-pyridine (0.5 Min THF; 0.235 mL, 0.117 mmol) was added dropwise. The vial was allowed to warm to rt and was 407 stirred for 1 h. Solvents were then removed and the crude material was redissolved in MeCN (3 mL) and stirred at rt for 3 h. Approximately one-half of the solvent was removed and column chromatography performed, which gave diyne 18 as a light yellow solid (0.003 g, 6% from 24). IH NMR (300 MHz, CH2Ch): [) 8.55 (br, 1H), 7.81 (d, 3JHH = 5.8 Hz, 1H), 7.65 (s, 4H), 7.35 (app t, 3JHH = 7.9 Hz, 1H), 7.28 (d, 3JHH = 7.0 Hz, 2H), 6.56 (d, 3JHH = 7.0 Hz, 2H), 6.46 (app t, 3JHH = 7.0 Hz, 1H), 3.27 (t, 3JHH = 7.6 Hz, 4H), 1.60 (m, 4H), 1.39 (m, 4H), 0.98 (t, 3JHH = 7.3 Hz, 6H). llB NMR (192.5 MHz, CD2Ch): [) 26.8. HRMS (El) calcd for C29H30BN3(M+) 431.25328, found 431.25011. Compound 28. A solution of ethylmagnesium bromide (1.0 M in THF; 0.44 mL, 0.44 mmol) was added to a solution of 4-(dibutylamino)phenylacetylene (0.100 g, 0.44 mmol in 2 mL THF) at rt. Gas evolution was observed, which ceased after approximately 30 min. The reaction was stirred an additional 2 h, and this solution was then added dropwise to a stirring solution of3 (0.100 g, 0.44 mmol in 3 mL THF) at rt. Solvent was removed and column chromatography was performed (EhO/pentane), which gave alkyne 28 as a yellow oil (0.145 g, 78%). IH NMR (300 MHz, CH2Ch): [) 7.58 (dd, 3JHH = 10.9,6.3 Hz, 1H), 7.31 (m,3H), 6.84 (d, 3JHH = 11.0 Hz, 1H), 6.55 (d, 3JHH = 8.9 Hz, 2H), 6.32 (app t, 3JHH = 6.4 Hz, 1H), 3.25 (t, 3JHH = 7.6 Hz, 4H), 1.57 (m, 4H), 1.39 (m, 4H), 0.98 (m, 15H), 0.62 (s, 6H). BC NMR (75 MHz, CD2Ch): [) 148.7, 143.5, 139.2, 133.2, 112.2, 111.7, 110.0, 109.5,51.2, 29.9,27.0,20.9, 19.6, 14.3, -1.8. liB NMR (192.5 MHz, CD2Ch): [) 29.0. FTIR (thin film) 2956,2930, 2859,2164, 1603, 1517, 1505, 1452, 1390, 1368, 1284, 1259, 1185, 408 1124, 1071,987,843,822,812,785,742,689 cm l . Compound 29. A solution of ethylmagnesium bromide (1.0 M in THF; 0.44 mL, 0.44 mmol) was added to a solution of4-cyanophenylacetylene (0.056 g, 0.44 mmol in 2 mL THF) at rt. Gas evolution was observed, which ceased after approximately 30 min. The reaction was stirred an additional 1 h, and this solution was then added dropwise to a stirring solution of3 (0.100 g, 0.44 mmol in 3 mL THF) at rt. Solvent was removed and column chromatography was performed (EtzO/pentane), which gave alkyne 29 as a yellow solid (0.090 g, 64%). IH NMR (500 MHz, CH2Ch): 67.65 (d, 3JHH = 7.6 Hz, 2H), 7.58 (m, 3H), 7.40 (d, 3JHH = 6.4 Hz, IH), 6.92 (d, 3JHH = 10.9 Hz, IH), 6.44 (app t, 3JHH = 6.4 Hz, IH), 0.96 (s, 9H), 0.62 (s, 6H). 13C NMR (125.8 MHz, CD2Ch): 6 144.4, 139.5, 132.7, 132.3, 129.4, 119.0, 113.3, 112.0, 105.7,26.8, 19.6, -2.0. liB NMR (192.5 MHz, CD2Ch): 628.6. FTIR (thin film) 2955, 2929, 2884, 2858, 2228, 1602, 1505, 1464, 1470, 1451, 1392, 1354, 1273, 1253, 1197, 1125, 1072, 1018,988,840, 787, 747, 696 em-I. Compound 30. A vial was charged with alkyne 28 (0.050 g, 0.119 mmol), (MeCN)3Cr(CO)3 (0.037 g, 0.143 mmol), and THF (1.5 mL), and was stirred at rt for 1 h. Solvents were then removed and column chromatography performed (Et20/pentane), giving complex 30 as a red, crystalline solid (0.044 g, 66%). IH NMR (500 MHz, CH2Ch): 67.32 (d, 3JHH = 9.0 Hz, 2H), 6.58 (d, 3JHH = 9.0 Hz, 2H), 6.01 (m, 2H), 5.20 (app t, 3J.4H = 6.1 Hz, 1H), 4.71 (d, 3JHH = 9.3 Hz, IH), 3.29 (t, 3JHH = 7.6 Hz, 4H), 1.57 (m, 4H), 1.39 (m, 4H), 0.98 (m, 15H), 0.74 (s, 3H), 0.44 (s, 3R). 13CNMR(75 MHz,CD2Ch): 6231.0,149.1,133.5,111.7,110.3,108.8,108.6,103.9, 409 88.3,83.2,51.2,29.9,27.3,20.9,20.2, 14.3, -0.9, -3.7. llB NMR (192.5 MHz, CD2Ch): 614.7. FTIR (thin film) 2957, 2932, 2861, 2167,1967,1897,1874,1605,1520,1371, 1287, 1111, 1052,989,813,668 em-I. Compound 31. A vial was charged with alkyne 29 (0.025 g, 0.080 mmol), (MeCN)3Cr(CO)3 (0.025 g, 0.095 mmol), and THF (2 mL), and was stirred at rt for 1 h. Solvents were then removed and column chromatography performed (Et20/pentane), giving complex 31 as a red, crystalline solid (0.028 g, 77%). IH NMR (300 MHz, CH2Ch): 67.62 (m, 4H), 6.03 (m, 2H), 5.24 (app t, 3JHH = 5.9 Hz, IH), 4.72 (d, 3JHH = 9.4 Hz, IH), 0.96 (m, 9H), 0.61 (s, 3H), 0.45 (s, 3H). BC NMR (125.8 MHz, CD2Ch): 6230.4, 132.9, 132.7, 132.5, 128.3, 108.2, 103.8,83.5,27.0,20.2, -1.1, -3.8. lIB NMR (192.5 MHz, CD2Ch): 613.6. FTIR (thin film) 2931, 2860, 2228, 1969, 1890, 1602, 1500, 1465, 1407, 1374, 1272, 1113,989,841,807, 792, 664 em-I. Compound 32. A solution ofHF-pyridine (0.5 Min THF; 0.174 mL, 0.087 mmol) was added dropwise to a solution of complex 30 (0.044 g, 0.079 mmol in 1 mL THF) at -20 cc. The reaction was allowed to warm to rt and was stirred for 1 h, whereupon the solvent was removed and column chromatography (EhO/pentane) was performed, providing complex 32 as an orange-red solid (0.020 g, 57%). IH NMR (500 MHz, CH2Ch): 67.34 (d, 3JHH = 9.0 Hz, 2H), 6.55 (d, 3JHH = 9.0 Hz, 2H), 6.15 (app t, 3JHH = 5.3 Hz, IH), 5.91 (dd, 3JHH = 9.7, 5.8 Hz, IH), 5.3 (hr, IH), 5.20 (app t, 3.fT-!H = 5.9 Hz, IH), 4.74 (d, 3J.I--IH = 9.4 Hz, 1H), 3.29 (t, 3J,T-fH = 7.6 Hz, 4H), 1.57 (m, 4H), 1.39 (m, 4H), 0.96 (t, 3JHH = 7.3 Hz, 6H). FTIR (thin film) 3359, 2958, 2932,2872,2168,1970,1898,1604,1520,1471,1441, 1369, 1288, 1223, 1102, 1046, 410 937,815,664,625 em-I. Compound 33. A solution ofHF-pyridine (0.5 Min THF; 0.121 mL, 0.061 mmol) was added dropwise to a solution of complex 31 (0.025 g, 0.055 mmol in 1 mL THF) at -20°C. The reaction was allowed to warm to rt and was stirred for 1 h, whereupon the solvent was removed and column chromatography (EhO/pentane) was performed, providing complex 33 as an orange-red solid (0.010 g, 53%). IH NMR (300 MHz, CH2Cb): () 7.64 (m, 4H), 6.19 (br app t, 1H), 5.91 (dd, 3JHH = 9.1,6.1 Hz, 1H), 5.4 (br, 1H), 5.29 (app t, 3JHH = 5.6 Hz, IH), 4.77 (d, 3JHH = 9.7 Hz, 1H). FTIR (thin film) 3356, 2230, 2073, 1969, 1889, 1472, 1266, 1178, 1105,839, 739, 663, 628 em-I. Compound 26. Complex 32 (0.020 g, 0.045 mmol) was dissolved in MeCN (5 mL) and stirred for 3 h at rt. Approximately one-half of the solvent was removed and column chromatography was performed (Et20/pentane) to give 26 as a light yellow solid (0.011 g, 79%). IH NMR (300 MHz, CH2Cb): () 8.31 (br, 1H), 7.76 (dd, 3JHH = 11.4,6.7 Hz, 1H), 7.32 (m, 4H), 6.87 (d, 3JHH = 11.5 Hz, 1H), 6.55 (d, 3JHH = 9.1 Hz, 1H), 6.34 (app t, 3JHH = 6.7 Hz, 1H), 3.29 (t, 3JHH = 7.6 Hz, 4H), 1.59 (m, 4H), 1.39 (m, 4H), 0.96 (t, 3JHH = 7.3 HZ,6H). BC NMR (125.8 MHz, CD2Cb): () 148.8, 144.6, 134.7, 133.7, 132 (br), 111.7, 111.2, 109.2, 106.6,51.2,29.9,20.8, 14.3. lIB NMR (192.5 MHz, CD2Cb): () 25.9. FTIR (thin film) 3376, 3074, 3028, 2957, 2931, 2871, 2165, 1606, 1533, 1518, 1460, 1420, 1402, 1369, 1350, 1286, 1222, 1187, 1123, 1105, 1075,991,926,814, 733, 680 em-I. Compound 27. Complex 33 (0.010 g, 0.0294 mmol) was dissolved in MeCN (5 411 mL) and stilTed for 3 hat rt. Approximately one-half of the solvent was removed and column chJOl11atography performed, which gave 27 as a light yellow solid (0.003 g, 50%). IH NMR (300 MHz, CH2Ch): 6 8.49 (br, 1H), 7.76 (dd, 1JH1'1 = 11.4,6.7 Hz, IH), 7.65 (s, 4H), 7.40 (app t 3.11111 = 7.6 Hz. 1H), 6.94 (d, .I.hll~ = 11.1 Hz, 1/--1),6.47 (app t, 3.11-1H = 6.4 Hz, 1I-l). I.lC NMR (125.8 MHz, C02C1 2): () 145.4, 134.9. 133.0, 132.9, 132.7, 128.9, 119.0, 112.4, 112.3. liB NMR (192.5 MHz, C02C12): 625.5. FTIR (thin tilm) 3366.3030.2229.2072, 1942. 1602, 1539, 1460, 1419, 1350, 1263, 1105, 1077,838, 735, I'll 'J , I h (() ... ,/ (ll! ('111 ~.I' ((Iii (r'~, \ '1 I J1 ( ( fill"""" ' , ,I '( \ I (ill1111.1 /' I1'11' J I' \ "" ~c~ 1',1........",...-·' f,'1./~ N(1) '. J ~.I, lr.~ .,(( \:1 , ". I /\ (' I) I,' I 1(",' \:( 1.1 ~.;' d'~ r')' ..... I·'~ )' ,~' .~. • ,("('/1 C(;) 1 r~( :1 ·'0.~~ (~)~' . f (' J~ I (:t~ I I f' . .. /'., C!,~ 0(31 ), t( ) 0(21 Figure K ORT!:::I) illustration of 16, with thermal ellipsoids drawn at the 35% probability level. Hydrogen atoms have been omitted for clarity. 412 X-ray Crystal Structure Determination. Crystals of 16 suitable for X-ray diffraction were obtained by evaporation of a solution of 16 in E120. Diffraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa- radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2. All non-H atoms were refined with anisotropic thermal parameters. H atoms were found on the residual density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, Broker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for C29H2sBCrN03Si are given in the following tables. Table 25. Crystal data and structure refinement for 18 (liu67). Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient F(OOO) Crystal size liu67 C29 H28 B Cr N 0 3 Si 529.42 173(2) K 0.71073 A Monoclinic P2(1)/n a =11.7332(19) A b =11.0286(17) A c = 21.993(4) A 2760.3(8) A3 4 1.274 IvIgim3 0.488 mm- 1 1104 0.31 x0.31 xO.l1 mm3 a= 90°. 13= 104.091(3t· y= 90°. 413 Theta range for data collection 1.91 to 27.000 • Index ranges -11<=h<=14, -13<=k<=13 , -28<=1<=28 Reflections collected 15944 Independent reflections 5863 [R(int) = 0.0279] Completeness to theta = 27.000 97.4% Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.9483 and 0.8635 Refinement method Pull-matrix least-squares on p2 Data / restraints / parameters 5863/0/437 Goodness-of-fit on p2 1.040 Pinal R indices [I>2sigma(l)] R1 = 0.0391, wR2 = 0.0937 R indices (all data) R1 = 0.0508, wR2 = 0.1014 Largest diff. peak and hole 0.442 and -0.230 e.A-3 Table 26. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (A2X 1(}3) for liu67. U(eg) is defined as one third of the trace of the orthogonalized Uij tensor. x y z U(eq) Cr(1) 903(1) 2297(1) 2107(1) 22(1) Si(1) -1024(1) 4271(1) 2780(1) 24(1) 0(1) -422(1) 119(1) 2382(1) 40(1) 0(2) 2129(1) 428(1) 1507(1) 37(1) 0(3) -839(2) 2651(2) 863(1) 52(1) N(1) 393(1) 3836(1) 2632(1) 23(1) B(1) 903(2) 4407(2) 2148(1) 25(1) C(1) 53(2) 989(2) 2280(1) 29(1) C(2) 1670(2) 1156(2) 1740(1) 26(1) C(3) -171(2) 2521(2) 1338(1) 33(1) C(4) 1053(2) 2976(2) 3041(1) 25(1) C(5) 2179(2) 2633(2) 3015(1) 26(1) C(6) 2677(2) 3055(2) 2534(1) 26(1) C(7) 2090(2) 3919(2) 2095(1) 24(1) C(8) -1615(2) 2940(2) 3120(1) 38(1) C(9) -2082(2) 4661(2) 2032(1) 34(1) C(10) -696(2) 5555(2) 3367(1) 31(1) C(11) 141(2) 5122(3) 3978(1) 42(1) C(12) -1863(2) 5959(3) 3505(1) 45(1) C(13) -144(2) 6641(2) 3116(1) 42(1) C(14) 280(2) 5414(2) 1711(1) 27(1) C(15) -112(2) 6194(2) 1336(1) 29(1) C(16) -615(2) 7121 (2) 890(1) 29(1) C(17) -432(2) 8339(2) 1043(1) 45(1) C(18) -912(3) 9224(2) 613(1) 53(1) C(19) -1581(2) 8916(2) 29(1) 50(1) C(20) -1774(3) 7718(3) -129(1) 56(1) 414 C(21) -1294(2) 6819(2) 297(1) 46(1) C(22) 2634(2) 4360(2) 1621(1) 26(1) C(23) 3108(2) 4818(2) 1255(1) 29(1) C(24) 3707(2) 5472(2) 860(1) 30(1) C(25) 3105(2) 6327(2) 431(1) 44(1) C(26) 3710(3) 7018(3) 89(1) 58(1) C(27) 4897(3) 6858(3) 160(1) 58(1) C(28) 5501(2) 6010(2) 574(1) 48(1) C(29) 4908(2) 5320(2) 926(1) 36(1) Table 27. Bond lengths [A] and angles [0] for liu67. 415 Cr(1)-C(2) Cr(1)-C(1) Cr(1)-C(3) Cr(1)-C(4) Cr(1)-N(1) Cr(1)-C(5) Cr(1)-C(6) Cr(1)-C(7) Cr(1)-B(1) Si(I)-N(1) Si(I)-C(9) Si(1)-C(8) Si(I)-C(10) O(l)-C(1) O(2)-C(2) O(3)-C(3) N(1)-C(4) N(1)-B(1) B(1)-C(7) B(1)-C(14) C(4)-C(5) C(4)-H(4) C(5)-C(6) C(5)-H(5) C(6)-C(7) C(6)-H(6) C(7)-C(22) C(8)-H(8A) C(8)-H(8B) C(8)-H(8C) C(9)-H(9A) C(9)-H(9B) C(9)-H(9C) C(1O)-C(13) C(1O)-C(1l) C(1 O)-C(12) C(11)-H(IIA) C(1l)-H(11B) C(1l)-H(11C) C(12)-H(12A) C(12)-H(12B) C(12)-H(12C) C(13)-H(13A) C(13)-H(13B) C(13)-H(13C) C(14)-C(15) C(15)-C(l6) C(16)-C(17) C(16)-C(2l) C(17)-C(18) C(17)-H(17) C(18)-C(19) 1.843(2) 1.845(2) 1.863(2) 2.1541(19) 2.2157(15) 2.2167(19) 2.2280(19) 2.2713(19) 2.329(2) 1.8336(16) 1.853(2) 1.857(2) 1.892(2) 1.158(2) 1.154(2) 1.152(2) 1.404(2) 1.482(3) 1.524(3) 1.533(3) 1.389(3) 0.95(2) 1.407(3) 0.92(2) 1.411(3) 0.906(19) 1.433(3) 0.97(3) 0.92(3) 0.92(3) 0.94(3) 0.93(3) 0.96(3) 1.528(3) 1.536(3) 1.539(3) 0.97(3) 0.97(3) 0.97(2) 1.01(3) 0.95(3) 0.99(3) 0.95(3) 0.96(2) 0.97(2) 1.202(3) 1.440(3) 1.388(3) 1.393(3) 1.379(3) 0.95(2) 1.375(4) 416 C(l8)-H(18) 0.93(3) C(19)-C(20) 1.371(4) C(l9)-H(l9) 0.97(3) C(20)-C(2l) 1.387(4) C(20)-H(20) 0.89(3) C(21)-H(2l) 0.88(3) C(22)-C(23) 1.197(3) C(23)-C(24) 1.436(3) C(24)-C(29) 1.392(3) C(24)-C(25) 1.398(3) C(25)-C(26) 1.383(4) C(25)-H(25) 0.89(2) C(26)-C(27) 1.374(4) C(26)-H(26) 0.87(3) C(27)-C(28) 1.375(4) C(27)-H(27) 0.91 (3) C(28)-C(29) 1.387(3) C(28)-H(28) 0.99(3) C(29)-H(29) 0.87(2) C(2)-Cr(l)-C(l) 84.45(9) C(2)-Cr(l)-C(3) 89.28(8) C(1)-Cr(l)-C(3) 90.65(9) C(2)-Cr(1)-C(4) 136.04(8) C(l)-Cr(l)-C(4) 89.82(8) C(3)-Cr(l)-C(4) 134.43(8) C(2)-Cr(l)-N(l) 166.81(7) C(l)-Cr(l)-N(l) 105.24(7) C(3)-Cr(l)-N(l) 99.37(7) C(4)-Cr(l)-N(l) 37.45(6) C(2)-Cr(l)-C(5) 102.37(8) C(1)-Cr(1)-C(5) 102.98(8) C(3)-Cr(1)-C(5) 162.75(8) C(4)-Cr(l)-C(5) 37.02(7) N(l)-Cr(l)-C(5) 67.10(6) C(2)-Cr(l)-C(6) 86.30(8) C(l)-Cr(l)-C(6) 134.64(8) C(3)-Cr(1)-C(6) 133.56(9) C(4)-Cr(l)-C(6) 67.42(7) N(l)-Cr(l)-C(6) 80.52(7) C(5)-Cr(l)-C(6) 36.90(7) C(2)-Cr(l )-C(7) 99.60(8) C(1)-Cr(1)-C(7) 169.00(7) C(3)-Cr(1)-C(7) 99.59(8) C(4)-Cr(l)-C(7) 80.15(7) N(l)-Cr(l)-C(7) 69.28(6) C(5)-Cr(1)-C(7) 66.22(7) C(6)-Cr(l)-C(7) 36.53(7) C(2)-Cr(1)-B(1) 134.73(8) C(l)-Cr(l)-B(l) 140.14(8) C(3)-Cr(l)-B(l) 84.07(8) C(4)-Cr(l)-B(l) 67.42(7) N(l)-Cr(l)-B(l) 37.94(6) C(5)-Cr(1)-B(1) C(6)-Cr(1)-B(1) C(7)-Cr(1)-B(1) N(1)-Si(1)-C(9) N(1 )-Si (1 )-C(8) C(9)-Si(1)-C(8) N(1)-Si(1)-C(10) C(9)-Si (1 )-C(10) C(8)-Si(1)-C(10) C(4)-N(1)-B(1) C(4)-N(1)-Si(1) B(1)-N(1)-Si(1) C(4)-N(1)-Cr(1) B(1)-N(1)-Cr(1) Si(1)-N(1 )-Cr(1) N(1)-B(1)-C(7) N(1)-B(1)-C(14) C(7)-B(1)-C(14) N(1)-B(1)-Cr(1) C(7)-B(1)-Cr(1) C(14)-B(1)-Cr(1) O(1)-C(l)-Cr(1) O(2)-C(2)-Cr(1 ) O(3)-C(3)-Cr(1 ) C(5)-C(4)-N(1) C(5)-C(4)-Cr(1) N(1)-C(4)-Cr(1) C(5)-C(4)-H(4) N(1)-C(4)-H(4) Cr(1)-C(4)-H(4) C(4)-C(5)-C(6) C(4)-C(5)-Cr(1) C(6)-C(5)-Cr(1 ) C(4)-C(5)-H(5) C(6)-C(5)-H(5) Cr(1)-C(5)-H(5) C(5)-C(6)-C(7) C(5)-C(6)-Cr(1) C(7)-C(6)-Cr(1) C(5)-C(6)-H(6) C(7)-C(6)-H(6) Cr(1)-C(6)-H(6) C(6)-C(7)-C(22) C(6)-C(7)-B(1) C(22)-C(7)-B(1) C(6)-C(7)-Cr(1 ) C(22)-C(7)-Cr(1) B(l)-C(7)-Cr(l) Si(1)-C(8)-H(8A) SiC1)-C(8)-H(8B) H(8A)-C(8)-H(8B) Si(1)-C(8)-H(8C) H(8A)-C(8)-H(8C) 78.70(7) 67.49(7) 38.66(7) 110.10(9) 108.00(10) 107.79(12) 105.95(8) 114.34(11) 110.51(11) 119.48(15) 116.40(12) 123.92(13) 68.89(10) 75.19(10) 131.62(8) 116.15(17) 122.96(17) 120.87(17) 66.87(10) 68.61(11) 134.72(14) 175.43(17) 178.59(17) 179.5(2) 122.60(17) 73.94(11) 73.66(10) 120.7(12) 116.7(12) 125.4(12) 120.98(18) 69.04(11) 71.99(11) 117.5(13) 121.3(13) 127.4(13) 121.01(17) 71.12(11) 73.41(11) 116.7(12) 122.2(12) 125.4(11) 119.80(17) 119.30(17) 120.86(17) 70.06(11) 131.14(13) 72.73(11) 104.5(17) 111.2(18) 104(2) 111.0(16) 114(2) 417 H(8B)-C(8)-H(8C) Si(1 )-C(9)-H(9A) Si(1 )-C(9)-H(9B) H(9A)-C(9)-H(9B) Si(1 )-C(9)-H(9C) H(9A)-C(9)-H(9C) H(9B)-C(9)-H(9C) C(13)-C(1O)-C(11) C(13)-C(10)-C(12) C(Il)-C(1O)-C(12) C(13)-C(1 O)-Si(1) C(1l)-C( lO)-Si( 1) CCI2)-CCI O)-Si(1) C(10)-C(11)-H(11A) C(1O)-C(11)-H(1lB) H(lIA)-C(11)-H(1lB) C(10)-C(1l)-H(11C) H(l1A)-C(11)-H(11C) H(llB )-C(1l)-H(11 C) C(1 0)-C(12)-H(12A) CClO)-C(12)-H(12B) H(l2A)-C(l2)-H(l2B) CClO)-CCI2)-H(12C) H(l2A)-CCI2)-H(12C) H(l2B)-C(12)-H(12C) C(10)-C(13)-H(13A) CClO)-CC13)-H(13B) H(13A)-CC13)-H(13B) C(10)-C(13)-H(13C) H(13A)-C(13)-H(13C) H(13B)-C(13)-H(13C) C(15)-C(14)-B(1) CC14)-C( 15)-C(16) C(17)-CCI6)-C(21) C(17)-C(16)-C(15) CC21 )-C( 16)-C(15) C(18)-C(17)-C(16) C(18)-C(17)-H(17) C(16)-C(17)-H(17) C(19)-C(18)-C(17) C(19)-C(18)-H(18) C( 17)-C(18)-H( 18) C(20)-C(19)-C(18) C(20)-C( 19)-H( 19) C(18)-C(19)-H(19) C( 19)-C(20)-C(21) CC19)-C(20)-H(20) C(21)-C(20)-H(20) C(20)-C(21 )-C( 16) C(20)-C(2l)-H(2l) C(16)-C(21)-H(2l) C(23)-C(22)-C(7) C(22)-C(23)-C(24) 112(2) 108.4(15) 109.8(15) 107(2) 114.8(16) 110(2) 106(2) 108.86(19) 108.7(2) 109.05(19) 111.95(14) 110.19(16) 108.01(15) 111.4(14) 113.2(14) 109(2) 109.3(14) 108(2) 106.1(19) 113.3(15) 107.1(16) 105(2) 110.0(15) 112(2) 109(2) 111.6(15) 109.7(14) 107(2) 110.2(14) 108(2) 110(2) 172.9(2) 178.3(2) 118.5(2) 120.63(18) 120.9(2) 120.4(2) 119.8(15) 119.8(15) 120.7(2) 121.2(18) 118.1(18) 119.8(2) 119.4(16) 120.8(16) 120.2(2) 122.8(17) 117.0(18) 120.5(2) 119.9(17) 119.7(17) 174.3(2) 174.1(2) 418 419 C(29)-C(24)-C(25) 118.9(2) C(29)-C(24)-C(23) 120.59(19) C(25)-C(24)-C(23) 120.4(2) C(26)-C(25)-C(24) 119.8(3) C(26)-C(25)-H(25) 120.2(15) C(24)-C(25)-H(25) 119.9(15) C(27)-C(26)-C(25) 120.5(3) C(27)-C(26)-H(26) 121(2) C(25)-C(26)-H(26) 118(2) C(26)-C(27)-C(28) 120.5(2) C(26)-C(27)-H(27) 123(2) C(28)-C(27)-H(27) 116(2) C(27)-C(28)-C(29) 119.7(3) C(27)-C(28)-H(28) 122.5(16) C(29)-C(28)-H(28) 117.8(16) C(28)-C(29)-C(24) 120.6(2) C(28)-C(29)-H(29) 121.7(15) C(24)-C(29)-H(29) 117.7(15) Symmetry transformations used to generate equivalent atoms: Table 28. Anisotropic displacement parameters (A2x 1(3)for liu67. The anisotropic displacement factor exponent takes the form: _2p2[ h2a*2U11 + ... + 2 h k a* b* U12] Ull U22 lF3 U23 U13 U12 Cr(1) 21(1) 19(1) 26(1) -1(1) 4(1) 1(1) Si(1) 22(1) 23(1) 29(1) -2(1) 7(1) 0(1) 0(1) 39(1) 32(1) 52(1) 1(1) 14(1) -9(1) 0(2) 42(1) 31(1) 38(1) -2(1) 12(1) 10(1) 0(3) 51(1) 51(1) 41(1) -2(1) -13(1) 8(1) N(1) 24(1) 20(1) 26(1) 0(1) 6(1) 3(1) B(1) 26(1) 21(1) 26(1) -3(1) 4(1) -2(1) C(1) 25(1) 29(1) 32(1) -4(1) 6(1) 2(1) C(2) 25(1) 24(1) 28(1) 4(1) 4(1) 0(1) C(3) 33(1) 24(1) 38(1) -4(1) 3(1) 4(1) C(4) 29(1) 21(1) 26(1) 2(1) 5(1) 1(1) C(5) 26(1) 21(1) 28(1) 1(1) 0(1) 2(1) C(6) 20(1) 24(1) 33(1) -6(1) 3(1) 1(1) C(7) 24(1) 20(1) 28(1) -4(1) 5(1) -2(1) C(8) 34(1) 33(1) 48(1) 1(1) 14(1) -6(1) C(9) 25(1) 42(1) 36(1) -1(1) 6(1) 5(1) C(10) 29(1) 30(1) 34(1) -7(1) 10(1) 0(1) C(11) 44(1) 43(2) 36(1) -9(1) 3(1) -2(1) C(12) 40(1) 50(2) 51(1) -17(1) 20(1) 2(1) C(13) 47(2) 28(1) 54(1) -10(1) 16(1) -5(1) C(14) 26(1) 24(1) 31(1) -2(1) 9(1) 1(1) C(15) 28(1) 26(1) 32(1) 0(1) 7(1) 0(1) C(16) 31(1) 26(1) 30(1) 3(1) 8(1) 3(1) C(l7) 60(2) 30(1) 35(1) -1(1) -6(1) 5(1) C(18) 76(2) 26(1) 48(1) 5(1) -1(1) 8(1) C(19) 64(2) 41(2) 40(1) 14(1) 3(1) 11(1) C(20) 75(2) 50(2) 33(1) 4(1) -9(1) -2(1) C(21) 62(2) 31(1) 38(1) -1(1) -1(1) -4(1) ------------ - 420 C(22) 25(1) 22(1) 30(1) -5(1) 4(1) -1(1) C(23) 29(1) 26(1) 31(1) -6(1) 7(1) 0(1) C(24) 38(1) 27(1) 26(1) -5(1) 10(1) -4(1) C(25) 52(2) 46(2) 35(1) 3(1) 12(1) 2(1) C(26) 90(2) 47(2) 39(1) 13(1) 21(1) 1(2) C(27) 88(2) 53(2) 42(1) -2(1) 33(1) -27(2) C(28) 54(2) 55(2) 42(1) -13(1) 23(1) -18(1) C(29) 42(1) 35(1) 31(1) -5(1) 12(1) -7(1) Table 29. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2X 1(3) for liu67. x Y z U(eq) H(4) 691(18) 2629(17) 3343(9) 25(5) H(5) 2558(18) 2062(19) 3301(9) 28(5) H(6) 3369(17) 2718(16) 2510(8) 17(5) H(8A) -2430(30) 3150(30) 3099(13) 72(9) H(8B) -1670(20) 2270(30) 2863(14) 68(9) H(8C) -1180(20) 2780(20) 3520(13) 57(8) H(9A) -2840(20) 4610(20) 2094(11) 52(7) H(9B) -2030(20) 4100(20) 1727(12) 51(7) H(9C) -1960(20) 5440(30) 1866(12) 62(8) H(11A) -200(20) 4460(20) 4168(11) 51(7) H(1lB) 900(20) 4870(20) 3925(10) 46(7) H(11C) 290(20) 5780(20) 4276(11) 46(7) H(12A) -2480(20) 6180(20) 3118(13) 64(8) H(12B) -2170(20) 5280(20) 3675(12) 57(8) H(12C) -1720(20) 6620(20) 3817(12) 56(7) H(13A) -30(20) 7300(20) 3402(12) 55(8) H(13B) -660(20) 6920(20) 2730(11) 43(6) H(13C) 610(20) 6420(20) 3042(11) 47(7) H(17) 30(20) 8560(20) 1442(12) 54(7) H(18) -770(30) 10030(30) 729(13) 74(9) H(19) -1930(20) 9530(20) -271(12) 60(8) H(20) -2190(30) 7480(20) -507(14) 67(9) H(21) -1420(20) 6050(20) 193(12) 53(8) H(25) 2340(20) 6460(20) 397(10) 40(7) H(26) 3320(30) 7570(30) -162(15) 75(10) H(27) 5330(30) 7310(30) -43(16) 88(11) H(28) 6360(20) 5870(20) 638(12) 62(8) H(29) 5266(19) 4770(20) 1188(10) 36(6) Table 30. Torsion angles [0] for liu67. C(9)-Si(1 )-N(1)-C(4) C(8)-Si(1 )-N(1)-C(4) C(1 OJ-SiC 1)-N(1)-C(4) C(9)-Si(1 )-N(1 )-B(1) C(8)-Si(1 )-N(1 )-B(1) C(1 OJ-SiC 1)-N(1 )-B(1) C(9)-Si(1)-N(1 )-Cr( I) C(8)-Si(1 )-N(I)-Cr(l) C(1 O)-Si(1)-N(1 )-Cr(1) C(2)-Cr(1 )-N(1 )-C(4) C(1)-Cr(1)-N(l)-C(4) C(3)-Cr(l)-N(l)-C(4) C(5)-Cr(1)-N(l)-C(4) C(6)-Cr(l)-N(l)-C(4) C(7)-Cr(l )-N(l)-C(4) B(l )-Cr(l)-N(l)-C(4) C(2)-Cr(I)-N(l)-B(l ) C(1)-Cr(l)-N(l)-B(1) C(3)-Cr(l)-N(l)-B(l) C(4)-Cr(l)-N(l)-B(1) C(5)-Cr(1)-N(1)-B(1) C(6)-Cr(1)-N(1)-B(l ) C(7)-Cr(l)-N(l)-B(l ) C(2)-Cr(I)-N(1 )-Si(l) C(1 )-Cr(I)-N(I)-Si(1) C(3)-Cr(1)-N(1 )-Si(1) C(4)-Cr(1)-N(1 )-Si(l) C(5)-Cr(1)-N(1 )-Si(1) C(6)-Cr(I)-N(I)-Si(1 ) C(7)-Cr(1)-N(1 )-Si(1) B(1)-Cr(I)-N(I)-Si(1 ) C(4)-N(l)-B(1)-C(7) Si(l)-N(1)-B(1 )-C(7) Cr( 1)-N(1)-B(1)-C(7) C(4)-N(1)-B(1 )-C(14) Si(l)-N(l)-B(l )-C(l4) Cr(l )-N(I)-B(1)-C(l4) C(4)-N(l )-B(1)-Cr(l) Si(1)-N(1)-B(1 )-Cr(1) C(2)-Cr(1 )-B(1)-N(1) C(1 )-Cr(l )-B(1 )-N(I) C(3)-Cr(1)-B(1)-N(1) C(4)-Cr(1)-B(1)-N(1) C(5)-Cr(l)-B(1 )-N(I) C(6)-Cr(1 )-B(1)-N(1) C(7)-Cr(1)-B(l )-N(I) e(2)-Cr(l )-B(l )-C(7) C(l)-Cr(I)-B(1)-C(7) C(3)-Cr(1)-B(I)-C(7) C(4)-Cr(1)-B(1 )-C(7) N(l)-Cr(l)-B(1 )-C(7) C(5)-Cr(1)-B(1 )-C(7) -148.69(15) -31.24(16) 87.18(15) 36.45(18) 153.90(16) -87.68(16) -64.24(14) 53.21(14) 171.64(10) -67.5(3) 68.84(l2) 162.09(l2) -29.08(11) -65.02(11) -101.13(l1) -130.36(l5) 62.9(3) -160.80(11) -67.54(12) 130.36(15) 101.28(11) 65.35(11) 29.24(10) -174.6(3) -38.30(12) 54.95(12) -107.14(15) -136.22(l2) -172.16(l2) 151.73(12) 122.50(15) 5.4(3) -179.89(l2) -49.34(l5) -175.85(l7) -1.1(3) 129.41(l8) 54.74(14) -130.55(l2) -163.39(10) 29.67(l6) 113.54(l1) -30.12(10) -67.11 (l0) -103.98(11) -133.01(15) -30.38(15) 162.68(12) -113.45(l2) 102.89(11) 133.01(l5) 65.90(11) 421 ----~---- C(6)-Cr(1)-B(1)-C(7) C(2)-Cr(I)-B(1 )-C(14) C(1)-Cr(I)-B(I)-C(14) C(3)-Cr(I)-B(1 )-C(14) C(4)-Cr(I)-B(1 )-C(14) N(1)-Cr(1)-B(1 )-C(14) C(5)-Cr( 1)-B(1 )-C(14) C(6)-Cr(1)-B(1)-C(14) C(7)-Cr(1)-B(l)-C(14) C(2)-Cr(1)-C(1 )-0(1) C(3 )-Cr(1)-C(1)-O(1) C(4)-Cr(1 )-C(1 )-0(1) N(1 )-Cr(1)-C(1)-O(1) C(5)-Cr(1)-C(1)-0(1 ) C(6)-Cr(1)-C(1)-0(1) C(7)-Cr(1 )-C(1 )-0(1) B(1 )-Cr(1)-C(1)-O( 1) C(1)-Cr(1)-C(2)-0(2) C(3)-Cr(1)-C(2)-0(2) C(4)-Cr(1 )-C(2)-0(2) N(1 )-Cr(1)-C(2)-0(2) C(5)-Cr(1)-C(2)-0(2) C(6)-Cr( 1)-C(2)-0(2) C(7)-Cr(1)-C(2)-0(2) B(1 )-Cr(1 )-C(2)-0(2) C(2)-Cr(1)-C(3)-0(3) C(1 )-Cr(1)-C(3)-0(3) C(4)-Cr(1 )-C(3)-0(3) N(l)-Cr(1 )-C(3)-0(3) C(5)-Cr(I)-C(3)-0(3) C(6)-Cr(1 )-C(3)-0(3) C(7)-Cr( 1)-C(3)-0(3) B(I)-Cr(1 )-C(3)-0(3) B(1 )-N(1)-C(4)-C(5) Si(1)-N(1)-C(4)-C(5) Cr(1)-N(1 )-C(4)-C(5) B(1)-N(I)-C(4)-Cr(1) Si(1 )-N(1)-C(4)-Cr(1) C(2)-Cr(1)-C(4)-C(5) C(1 )-Cr(1)-C(4)-C(5) C(3)-Cr(1 )-C(4)-C(5) N(1)-Cr(1 )-C(4)-C(5) C(6)-Cr(1 )-C(4)-C(5) C(7)-Cr(1 )-C(4)-C(5) B(1 )-Cr(1 )-C(4)-C(5) C(2)-Cr(1 )-C(4)-N(1) C(1)-Cr(1 )-C(4)-N(1) C(3)-Cr(l )-C(4)-N (l) C(5)-Cr(1)-C(4)-N(1 ) C(6)-Cr(1 )-C(4)-N(1) C(7)-Cr(1 )-C(4)-N(1) B(1 )-Cr(1 )-C(4)-N(1) N(1)-C(4)-C(5)-C(6) 29.02(10) 82.4(2) -84.5(2) -0.64(19) -144.3(2) -114.2(2) 178.7(2) 141.8(2) 112.8(2) 18(2) 107(2) -119(2) -153(2) -84(2) -62(2) -95(2) -172(2) 27(7) -64(7) 111(7) 165(7) 129(7) 163(7) -163(7) -145(7) 79(26) -5(26) -96(26) -111(26) -148(100) 163(100) 179(100) -146(26) 0.2(3) -174.88(15) 58.02(17) -57.80(15) 127.10(10) 30.36(17) 112.16(13) -157.10(13) -131.96(17) -27.50(12) -63.29(12) -101.47(13) 162.32(11) -115.88(11) ~25.14(16) 131.96(17) 104.46(12) 68.67(10) 30.49(10) -5.9(3) 422 Cr(1)-C(4)-C(5)-C(6) N(1)-C(4)-C(5)-Cr(1) C(2)-Cr(1)-C(5)-C(4) C(1)-Cr(1 )-C(5)-C(4) C(3)-Cr(1)-C(5)-C(4) N(1 )-Cr(1 )-C(5)-C(4) C(6)-Cr(1)-C(5)-C(4) C(7)-Cr(1)-C(5)-C(4) B(1)-Cr(1)-C(5)-C(4) C(2)-Cr(1)-C(5)-C(6) C(1 )-Cr(1)-C(5)-C(6) C(3)-Cr(1 )-C(5)-C(6) C(4)-Cr(1)-C(5)-C(6) N(1 )-Cr(1 )-C(5)-C(6) C(7)-Cr(1 )-C(5)-C(6) B(1)-Cr(1)-C(5)-C(6) C(4)-C(5)-C(6)-C(7) Cr(1 )-C(5)-C(6)-C(7) C(4)-C(5)-C(6)-Cr(1) C(2)-Cr(1 )-C(6)-C(5) C(1)-Cr(1)-C(6)-C(5) C(3)-Cr(1)-C(6)-C(5) C(4)-Cr(I)-C(6)-C(5) N(1)-Cr(1 )-C(6)-C(5) C(7)-Cr(1)-C(6)-C(5) B(1 )-Cr(1)-C(6)-C(5) C(2)-Cr(1)-C(6)-C(7) C(1 )-Cr(1)-C(6)-C(7) C(3)-Cr(1)-C(6)-C(7) C(4)-Cr(1 )-C(6)-C(7) N(1)-Cr(1)-C(6)-C(7) C(5)-Cr(1)-C(6)-C(7) B(I)-Cr(I)-C(6)-C(7) C(5)-C(6)-C(7)-C(22) Cr(1 )-C(6)-C(7)-C(22) C(5)-C(6)-C(7)-B(1 ) Cr(1)-C(6)-C(7)-B(1) C(5)-C(6)-C(7)-Cr(1) N(1)-B (1 )-C(7)-C(6) C(14)-B(1)-C(7)-C(6) Cr(1)-B (1 )-C(7)-C(6) N(1)-B(1)-C(7)-C(22) C(14)-B(1 )-C(7)-C(22) Cr(1)-B (1)-C(7)-C(22) N(1)-B(1 )-C(7)-Cr(1) C(14)-B(1 )-C(7)-Cr(1) C(2)-Cr(1)-C(7)-C(6) C(1)-Cr(1)-C(7)-C(6) C(3)-Cr(1 )-C(7)-C(6) C(4)-Cr(1 )-C(7)-C(6) N(1 )-Cr(1 )-C(7)-C(6) C(5)-Cr(1)-C(7)-C(6) B(1)-Cr(1)-C(7)-C(6) 51.96(17) -57.89(16) -158.95(12) -71.88(13) 69.5(3) 29.39(11) 134.76(18) 105.89(13) 67.34(12) 66.29(13) 153.36(12) -65.2(3) -134.76(18) -105.37(12) -28.87(11) -67.42(12) 5.4(3) 56.11(16) -50.66(17) -116.34(12) -37.88(16) 158.19(13) 27.58(11) 64.23(11) 132.07(17) 101.45(13) 111.60(12) -169.94(11) 26.12(16) -104.48(12) -67.84(11) -132.07(17) -30.61(11) 178.18(17) -126.78(17) 0.5(3) 55.55(16) -55.04(16) -5.8(3) 175.47(17) -54.27(15) 176.60(16) -2.2(3) 128.08(17) 48.52(15) -130.26(18) -70.23(12) 40.6(4) -161.12(12) 65.14(11) 102.41(11) 29.15(11) 131.15(16) 423 C(2)-Cr(1)-C(7)-C(22) C(1 )-Cr(1)-C(7)-C(22) C(3)-Cr(1)-C(7)-C(22) C(4)-Cr(1)-C(7)-C(22) N(I)-Cr(1 )-C(7)-C(22) C(5)-Cr(I)-C(7)-C(22) C(6)-Cr(1 )-C(7)-C(22) B(1 )-Cr(1)-C(7)-C(22) C(2)-Cr(1)-C(7)-B(1) C(1 )-Cr(1)-C(7)-B(1) C(3)-Cr(1 )-C(7)-B(1) C(4)-Cr(1 )-C(7)-B(1) N(I)-Cr(1)-C(7)-B(1) C(5)-Cr(I)-C(7)-B(1) C(6)-Cr(I)-C(7)-B(I) N(I)-Si(I)-C(10)-C(13) C(9)-Si(1)-C(10)-C(13) C(8)-Si(1)-C(10)-C(13) N(1)-Si(1)-C(1O)-C(11) C(9)-Si(1 )-C(1 O)-C(1l) C(8)-Si(1)-C(1O)-C(11) N(1)-Si(1 )-C(1 0)-C(12) C(9)-Si(1 )-C(1 0)-C(12) C(8)-Si(1 )-C(1 0)-C(12) N(I)-B(I)-C(14)-C(15) C(7)-B(I)-C(14)-C(15) Cr(1 )-B(l)-C(14)-C(15) B(1 )-C(14)-C(15)-C(16) C(14)-C(15)-C(16)-C(17) C(14)-C(15)-C(16)-C(21) C(21 )-C(16)-C(17)-C(18) C(15)-C(16)-C(17)-C(18) C(16)-C(17)-C(18)-C(19) C(17)-C(18)-C(19)-C(20) C(18)-C(19)-C(20)-C(21) C(19)-C(20)-C(21)-C(16) C(17)-C(16)-C(2l)-C(20) C(15)-C(16)-C(21)-C(20) C(6)-C(7)-C(22)-C(23) B(1)-C(7)-C(22)-C(23) Cr(1)-C(7)-C(22)-C(23) C(7)-C(22)-C(23)-C(24) C(22)-C(23)-C(24)-C(29) C(22)-C(23)-C(24)-C(25) C(29)-C(24)-C(25)-C(26) C(23)-C(24)-C(25)-C(26) C(24)-C(25)-C(26)-C(27) C(25)-C(26)-C(27)-C(28) C(26)-C(27)-C(28)-C(29) C(27)-C(28)-C(29)-C(24) C(25)-C(24)-C(29)-C(28) C(23)-C(24)-C(29)-C(28) Symmetry transformations used to generate equivalent atoms: 42.42(18) 153.3(4) -48.47(19) 177.79(19) -144.94(19) 141.80(19) 112.6(2) -116.2(2) 158.63(11) -90.5(4) 67.73(12) -66.00(11) -28.73(10) -102.00(11 ) -131.15(16) 60.10(17) -61.34(19) 176.84(17) -61.20(17) 177.36(16) 55.54(18) 179.76(16) 58.33(19) -63.49(19) -174.5(16) 4.2(18) -85.5(17) 158(6) 105(7) -75(7) -0.2(4) 179.7(2) 0.3(4) -0.1(5) -0.1 (5) 0.2(5) -0.1(4) -179.9(2) -104(2) 73(2) 167(2) 5(4) 89(2) -87(2) -1.0(3) 175.0(2) 0.8(4) ()lfLL\ V' • .&. \.-11 -0.8(4) 0.6(3) 0.3(3) -175.68(19) 424 425 Figure 9. ORTEP illustration of 12, with thermal ellipsoids drawn at the 35% probability level. X-ray Crystal Structure Determination. Crystals of 12 suitable for X-ray diffraction were obtained by evaporation ofa solution of12 in Et20. DiiJraction intensity data were collected with a Bruker Smart Apex CCD diffractometer at 173(2) K using MoKa - radiation (0.71073 A). The structure was solved using direct methods, completed by subsequent difference Fourier syntheses, and refined by full matrix least-squares procedures on F2. All non-1-1 atoms \vere refined with anisotropic LhermaJ parameters. H aToms were found on the residuai density map and refined with isotropic thermal parameters. The Flack parameter is 0.00(8). All software and sources scattering factors are contained in the SHELXTL (6.10) program package (G.Sheldrick, 426 Bruker XRD, Madison, WI). Crystallographic data and some details of data collection and crystal structure refinement for C2oH14BN are given in the following tables. Table 31. Crystal data and structure refinement for 12 (Iiu70a). a= 90°. Monoclinic ~= 108.420(2)°. y = 90°. Identification code Empirical formula Pormula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Volume Z Density (calculated) Absorption coefficient P(OOO) Crystal size Theta range for data collection Index ranges Reflections collected Independent reflections Completeness to theta = 27.000 Absorption correction Max. and min. transmission Refinement method Data / restraints / parameters Goodness-of-fit on p2 Final R indices [I>2sigma(l)J R indices (all data) Largest diff. peak and hole liu70a C20 Hl4 B N 279.13 173(2) K 0.71073 A P2(l)/c a = 9.9028(13) A b= 17.214(2) A c = 9.5769(13) A 1548.9(4) A3 4 1.197 Mg/m3 0.068 mm- 1 584 0.23 x 0.12 x 0.08 mm3 2.17 to 27.00°. -12<=h<=12, -21<=k<=21, -12<=1<=12 17029 3382 [R(int) = 0.0245] 100.0 % Semi-empirical from equivalents 0.9945 and 0.9844 Pull-matrix least-squares on p2 3382/0/256 1.035 R1 = 0.0465, wR2 = 0.1059 R1 = 0.0595, wR2 = 0.1147 0.219 and -0.223 e.A-3 Table 32. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (A2x 1()3) for liu70a. U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. 427 N(1) N(1A) B(1) B(1A) C(1) C(2) C(3) C(3A) C(4) C(4A) C(5) C(6) C(7) C(8) C(9) C(10) C(1l) C(12) C(13) C(14) C(15) C(16) C(17) C(18) C(19) C(20) Table 33. x y z 3364(1) 2267(1) 6575(1) 4784(1) 1005(1) 8182(2) 2833(2) 1981(1) 7687(2) 3634(1) 1293(1) 8560(1) 4507(2) 1948(1) 6276(2) 5207(2) 1330(1) 7045(2) 4784(1) 1005(1) 8182(2) 3364(1) 2267(1) 6575(1) 3634(1) 1293(1) 8560(1) 2833(2) 1981 (1) 7687(2) 3214(1) 939(1) 9741(1) 2794(1) 675(1) 10690(1) 2268(1) 338(1) 11793(1) 1375(2) -310(1) 11461(2) 847(2) -629(1) 12506(2) 1205(2) -316(1) 13895(2) 2095(2) 320(1) 14244(2) 2622(2) 647(1) 13201(2) 1544(2) 2365(1) 7912(1) 499(2) 2661(1) 8061(1) -797(1) 2990(1) 8168(2) -1373(2) 3651(1) 7364(2) -2668(2) 3934(1) 7403(2) -3369(2) 3575(1) 8267(3) -2771(2) 2937(1) 9099(3) -1494(2) 2643(1) 9056(2) Bond lengths [A] and angles [0] for liu70a. U(eq) 34(1) 36(1) 29(1) 29(1) 38(1) 39(1) 36(1) 34(1) 29(1) 29(1) 33(1) 33(1) 30(1) 40(1) 43(1) 42(1) 47(1) 39(1) 33(1) 34(1) 35(l) 53(1) 71(1) 76(1) 74(1) 50(1) N(l)-C(l) N(l)-B(1) N(1)-H(1N) N(1A)-B(1A) N(1A)-C(2) N(1A)-H(3) B(1)-C(13) B(l)-B(1A) B(1A)-C(5) C(1)-C(2) C(1)-H(1) C(2)-H(2) C(5)-C(6) C(6)-C(7) C(7)-C(l2) C(7)-C(8) C(8)-C(9) C(8)-H(8) C(9)-C(10) C(9)-H(9) 1.3676(18) 1.4172(18) 0.898(18) 1.3906(18) 1.4006(19) 0.983(16) 1.5118(19) 1.5198(19) 1.4564(18) 1.353(2) 0.994(16) 0.966(16) 1.2015(18) 1.4406(18) 1.3875(19) 1.3946(19) 1.381(2) 0.962(18) 1.374(2) 0.973(19) C(1 0)-C(11) C(1O)-H(10) C(11)-C(12) C(11)-H(11) C(12)-H(12) C(13)-C(14) C(14)-C(15) C( 15)-C(20) C(15)-C(16) C(16)-C(17) C(16)-H(16) C(17)-C(18) C(17)-H(17) C(18)-C(19) C(18)-H(18) C(19)-C(20) C(19)-H(19) C(20)-H(20) C(1)-N(1)-B(1) C(1)-N(1)-H(1N) B(1)-N(1)-H(1N) B(1A)-N(1A)-C(2) B(1A)-N(1A)-H(3) C(2)-N(1A)-H(3) N(1)-B(1)-C(13) N(1)-B(1)-B(1A) C(13)-B(1)-B(1A) N(1A)-B(lA)-C(5) N(1A)-B(1A)-B(1) C(5)-B(1A)-B(1) C(2)-C(1)-N(1) C(2)-C(1)-H(1) N(l)-C(l)-H(l) C(1)-C(2)-N(1A) C(1)-C(2)-H(2) N(1A)-C(2)-H(2) C(6)-C(5)-B(1A) C(5)-C(6)-C(7) C(12)-C(7)-C(8) C(12)-C(7)-C(6) C(8)-C(7)-C(6) C(9)-C(8)-C(7) C(9)-C(8)-H(8) C(7)-C(8)-H(8) C(10)-C(9)-C(8) C(10)-C(9)-H(9) C(8)-C(9)-R(9) C(9)-C(10)-C(11) C(9)-C(1 0)-H(10) C(11)-C(10)-H(10) C(10)-C(11)-C(12) C(10)-C(11)-H(11) 1.378(2) 0.974(17) 1.385(2) 0.984(18) 0.990(17) 1.2016(19) 1.4354(19) 1.388(2) 1.392(2) 1.384(3) 1.01(2) 1.383(3) 0.96(2) 1.376(3) 0.96(2) 1.375(2) 1.00(2) 0.96(2) 123.07(12) 117.2(11) 119.8(11) 122.04(13) 119.0(9) 119.0(9) 119.06(12) 115.54(12) 125.40(12) 120.74(12) 117.55(12) 121.70(11) 121.16(13) 122.9(9) 115.9(9) 120.63(13) 120.2(9) 119.2(9) 175.99(14) 177.98(15) 118.45(12) 121.21(12) 120.34(12) 120.69(14) 120.7(11) 118.6(11) 120.28(14) 119.4(10) 120.3(10) 119.72(14) 119.9(10) 120.4(10) 120.41(14) 120.8(11) 428 C(12)-C(11)-H(11) 118.8(11) C(11)-C(12)-C(7) 120.45(14) C(11)-C(12)-H(12) 121.6(9) C(7)-C(12)-H(12) 117.9(9) C(14)-C(13)-B(1) 178.40(15) C(13)-C(14)-C(15) 176.73(15) C(20)-C(l5)-C(16) 119.59(15) C(20)-C(15)-C(14) 120.22(13) C(16)-C(15)-C(14) 120.18(14) C(17)-C(16)-C(15) 119.63(19) C(17)-C(16)-H(16) 119.9(12) C(15)-C(16)-H(16) 120.4(13) C(18)-C(17)-C(16) 120.3(2) C(18)-C(17)-H(17) 120.0(13) C(16)-C(17)-H(17) 119.8(14) C(19)-C(18)-C(17) 119.85(18) C(19)-C(18)-H(18) 119.7(14) C(17)-C(18)-H(18) 120.4(14) C(20)-C(19)-C(18) 120.5(2) C(20)-C(19)-H(19) 118.9(14) C(18)-C(19)-H(19) 120.6(14) C(19)-C(20)-C(15) 120.08(19) C(19)-C(20)-H(20) 121.5(11) C(15)-C(20)-H(20) 118.4(11) Symmetry transformations used to generate equivalent atoms: Table 34. Anisotropic displacement parameters (A2X 1()3)for liu70a. The anisotropic displacement factor exponent takes the form: _2p2[ h2a*2Ull + ... + 2 h k a* b* Ul2] 429 N(l) N(1A) B(1) B(1A) C(1) C(2) C(3) C(3A) C(4) C(4A) C(5) C(6) C(7) C(8) C(9) C(10) C(11) C(12) C(13) C(14) C(15) C(16) 36(1) 36(1) 31(1) 33(1) 37(1) 34(1) 36(1) 36(1) 33(1) 31(1) 36(1) 37(1) 31(1) 50(1) 45(1) 45(1) 56(1) 44(1) 39(1) 40(1) 36(1) 68(1) U22 34(1) 35(1) 27(1) 28(1) 46(1) 48(1) 35(1) 34(1) 28(1) 27(1) 29(1) 29(1) 28(1) 36(1) 34(1) 43(1) 54(1) 37(1) 29(1) 30(1) 35(1) 53(1) 34(1) 36(1) 28(1) 28(1) 35(1) 41(1) 36(1) 34(1) 28(1) 28(1) 33(1) 34(1) 32(1) 35(1) 53(1) 45(1) 35(1) 39(1) 32(1) 32(1) 33(1) 36(1) U23 7(1) 6(1) -1(1) -1(1) 5(1) 2(1) 6(1) 7(1) -1(1) -1(1) 1(1) 3(1) 5(1) -4(1) 3(1) 11(1) -4(1) -3(1) 4(1) 3(1) -5(1) 4(1) 14(1) 13(1) 10(1) 11(1) 19(1) 18(1) 13(1) 14(1) 11(1) 10(1) 11(1) 12(1) 11(1) 13(1) 17(1) 23(1) 20(1) 16(1) 14(1) 14(1) 11(1) 16(1) 4(1) 7(1) -2(1) -1(1) 0(1) 6(1) 7(1) 4(1) -1(1) -2(1) 5(1) 6(1) 6(1) -5(1) -6(1) 4(1) -7(1) -7(1) -1(1) -1 (1) 1(1) 24(1) 430 C(17) 69(1) 78(1) 50(1) -12(1) -2(1) 39(1) C(18) 35(1) 87(2) 101(2) -44(1) 12(1) 9(1) C(19) 56(1) 62(1) 122(2) -23(1) 56(1) -11(1) C(20) 52(1) 41(1) 69(1) -3(1) 35(1) -3(1) Table 35. Hydrogen coordinates (x 104) and isotropic displacement parameters (A2X 1()3) for liu70a. x y z U(eq) H(1) 4783(16) 2198(9) 5471(17) 46(4) H(1N) 2939(17) 2675(10) 6025(19) 50(5) H(2) 6020(17) 1116(9) 6830(17) 44(4) H(3) 5326(17) 565(9) 8740(17) 42(4) H(8) 1124(19) -524(10) 10480(20) 60(5) H(9) 223(19) -1079(11) 12266(19) 60(5) H(10) 842(17) -549(10) 14631(19) 52(5) H(11) 2377(19) 545(10) 15240(20) 61(5) H(12) 3252(18) 1108(10) 13426(18) 52(5) H(16) -870(20) 3915(12) 6730(20) 87(7) H(17) -3080(20) 4382(13) 6830(20) 87(7) H(18) -4250(30) 3783(13) 8330(20) 93(7) H(19) -3260(20) 2679(14) 9740(30) 95(7) H(20) -1071(19) 2190(12) 9620(20) 67(6) Table 36. Torsion angles [0] for liu70a. C(1)-N(1)-B(1)-C(13) C( 1)-N( l)-B(1)-B(1A) C(2)-N(lA)-B(lA)-C(5) C(2)-N(lA)-B(lA)-B(1) N(1)-B(1)-B(1A)-N(lA) C(13)-B(1)-B(1A)-N(1A) N(1)-B(1)-B(1A)-C(5) C(13)-B(1)-B(1A)-C(5) B(1 )-N(1)-C(1)-C(2) N(1 )-C(1)-C(2)-N(1 A) B(1A)-N(1A)-C(2)-C(1) N(lA)-B(lA)-C(5)-C(6) B(1 )-B(1A)-C(5)-C(6) B(1A)-C(5)-C(6)-C(7) C(5)-C(6)-C(7)-C(12) C(5)-C(6)-C(7)-C(8) C(12)-C(7)-C(8)-C(9) C(6)-C(7)-C(8)-C(9) C(7)-C(8)-C(9)-C(10) C(8)-C(9)-C(1 0)-C(11) C(9)-C(10)-C(11)-C(12) C(lO)-C(11)-C(12)-C(7) C(8)-C(7)-C(12)-C(11) C(6)-C(7)-C(12)-C(11) N(1 )-B(1 )-C(13)-C(14) B(1A)-B(1 )-C(13)-C(14) B(1 )-C(13)-C(14)-C(15) -178.80(13) 0.93(19) 179.51(13) 0.2(2) -0.90(18) 178.81(13) 179.79(12) -0.5(2) -0.2(2) -0.6(2) 0.6(2) -172(2) 7(2) 94(4) 176(100) -4(4) 0.6(2) -178.94(13) -0.5(2) -0.1(2) 0.5(2) -0.4(2) -0.2(2) 179.36(13) 75(5) -105(5) 4(7) C(13)-C(14)-C(15)-C(20) C(13)-C(14)-C(15)-C(16) C(20)-C(15)-C(16)-C(17) C(14)-C(15)-C(16)-C(17) C(15)-C(16)-C(17)-C(l8) C(16)-C(17)-C(18)-C(l9) C(17)-C(18)-C(19)-C(20) C(18)-C(19)-C(20)-C(15) C(16)-C(15)-C(20)-C(19) C(14)-C(15)-C(20)-C(19) Symmetry transformations used to generate equivalent atoms: 92(3) -87(3) -3.1 (2) 175.95(15) 1.7(3) 0.5(3) -1.3(3) -0.1 (3) 2.3(3) -176.73(16) 431 432 APPENDIXD SYNTHESIS AND CHARACTERIZATION OF NITROLIPIDS D.l. Introduction The interest in conjugated organic molecules has grown significantly over the last several decades. The incorporation of boron in conjugated materials has been shown to impart unique properties relative to their carbonaceous analogs. 1,2 The fundamental consequences of replacing CC units with BN units in tolan derivatives provides a glimpse at the potential of 1,2-azaborine heterocycles in materials applications. D.2. Experimental D.2.l. General THF was distilled over Na/benzophenone. CH2Ch was distilled over CaH2. Commercially available reagents were used as received. Thin layer chromatography was performed on Sigma-Aldrich TLC plates (general purpose, silica gel on polyester with UV indicator). Column chromatography was performed on Sorbent Technologies silica gel (60 A). 1H and B C NMR data were collected on a Varian spectrometer at 300 MHz and 75 MHz, respectively. IR spectroscopy data were coiiected on a Nicolet Magna FT- IR 550 spectrometer. High-resolution mass spectrometry data were collected by Jeff 433 Morre at Oregon State University, Environmental Health Sciences Center on a lEOL MSRoute Spectrometer in chemical ionization positive ionization mode. I-Nitrononane (9). Silver nitrite (24 g, 0.156 mol) was added to a flask protected from light with aluminum foil, suspended in E120, and purged with N2. 1- bromononane (21 g, 0.101 mol) was then added and the solution stirred at rt for 7 d. Solids were then removed by passing the solution through a plug of celite. The solvent was removed under vacuum and 9 purified by vacuum distillation (88°C, 0.1 Torr) in 60% yield (10.5 g) as a faintly yellow liquid. IH NMR (300 MHz, CDCb) [) 4.35 (t, J = 8 Hz, 2H), 1.96 (m, 2H), 1.25 (br m, 12H), 0.82 (t, J= 7.5 Hz, 3H); l3C NMR (75 MHz, CDCb) [) 77.8, 31.9, 29.3, 29.2, 28.9, 27.5,26.3,22.7, 14.1; IR (KBr) v 2927, 2857, 1555, 1466, 1436, 1382, 1136,874, 723, 613 em-I. Compound 10. Oleic acid (20.0 g, 0.071 mol) dissolved in dry CH2Ch (200 mL) in an oven-dried flask was cooled to -78°C with stirring under O2. 03 was then bubbled into the solution until a faint blue color was observed (45 min.), after which the solution was purged with N2 for 20 min. and brought to rt. Dimethylsulfide (7.3 mL, 0.10 mol) was added via syringe and the solution stirred for 3 h. Excess Me2S and solvent were then removed under reduced pressure and the mixture dissolved in EtOAc (l00 mL). The solution was then washed three times with satd. NaCl soln., dried with MgS04, and solvent removed under vacuum. 10 was then purified by column chromatography (1: 1 hexanes: ethyl acetate) in 90% yield as a colorless liquid. 434 IH NMR (300 MHz, CDCh) () 11.4 (br s, IH), 9.68 (t, J= 1.8 Hz, IH), 2.41 (t, J = 7.5 Hz, 2H), 2.35 (t, J= 7.5 Hz, 2H), 1.6 (br m, 4H), 1.25 (br m, 6H). Compound 11. A flask was charged with 10 (2.5 g, 15 mmol), N,N'- dicyclohexylcarbodiimide (DCC) (3.5 g, 17 mmol), and CH2Ch (50 mL), and cooled to o°C under N2. N,N-dimethyl-4-aminopyridine (DMAP) (50 mg) was then added and the solution stirred for 30 minutes, after which allyl alcohol was added and the solution stirred for 2 h. The reaction was then warmed to rt and stirred overnight. The solution was passed through a plug of silicalcelite, and solvents were removed under reduced pressure. Allyl ester 11 was purified by vacuum distillation (110 °C, 0.1 Torr) in 65% yield (2.0 g, colorless liquid) IH NMR (300 MHz, CDCh) () 9.74 (t, J= 1.8 Hz, IH), 5.88 (m, IH), 5.22 (m, 2H), 4.55 (d, J = 9.6 Hz, 2H), 2.40 (t, J = 7.5 Hz, 2H), 2.30 (t, J = 7.5 Hz, 2H), 1.60 (br m,4H), 1.32 (br m, 6H); 13C NMR (75 MHz, CDCh) () 202.3, 172.9, 132.1, 117.7,64.5, 43.5,33.8,28.7,28.6,28.5,24.5,21.6; IR (KBr) v 2934, 2858, 2720, 1736, 1649, 1458, 1418, 1378, 1174, 1105,991,933 em-I. Compound 12. Nitroalkane 9 (1.0 eq.) and aldehyde 11 (1.2 eq.) were added to a flask along with EtOAc (2 M in aldehyde). 1,8-Diazabicyclo[5.4.0]undec-7-ene (0.1 eq.) was then added under N2at rt and the solution stirred 24 h. The solution was then partitioned with EhO and 1 M HCI, the aqueous layer extracted three times with EhO, and the combined organic layer washed with brine and dried over MgS04 • The drying agent was then filtered and solvents removed under vacuum. Product 12 (colorless oil) 435 was purified by column chromatography (5% EtOAc in hexanes) as a mixture of diastereomers (75-85% yield): IH NMR (300 MHz, CDCb) b 5.88 (m, 1H), 5.22 (m, 2H), 4.60 (d, J= 9.6 Hz, 2H), 4.45 (m, 1H), 3.95 (m, 1H), 2.40 (t, J = 7.5 Hz, 2H), 2.10 (br m, 2H), 1.80 (br m, 2H), 1.65 (br m, 2H), 1.4 (br m, 20H), 0.92 (t, J= 7.5 Hz, 3H); BC NMR (75 MHz, CDCb) b 173.7,132.5,118.3,93.1,92.6,72.5,72.2,65.2,34.4,33.7, 33.3, 32.0, 30.7, 29.4,29.3,29.2,29.1,28.2,26.2,25.9,25.7,25.4,25.0, 22.8, 14.3; IR (KBr) v 3481, 2928,2857,1736,1649,1552,1458,1379,1175,1108,989,931, 733 em-I. Compound 13. Hydroxy-nitro intermediate 12 (2.0 g) was added to a flask containing acetic anhydride (as solvent, approximately 0.1 M in starting material) and p- toluenesulfonic acid (l-5mol%), whereupon the solution was stirred under N2, overnight, at rt. The solution was partitioned with EhO and H20, the aqueous layer extracted three times with EhO, and the combined organic layer washed once with brine. The organic layer was dried over MgS04, and solvents removed under vacuum (azeotropic removal of acetic anhydride/acetic acid was achieved by addition of 3 x 20 mL toluene), after which the desired product 13 (mixture of diastereomers) was purified by column chromatography (5% EtOAc in hexanes) as a colorless liquid in 99% yield: IH NMR (300 MHz, CDCb) b 5.88 (m, 1H), 5.22 (m, 2H), 5.15 (m, 1H), 4.58 (m, 1H), 4.56 (d, J= 9.6 Hz, 2H), 2.25 (t, J= 7.5 Hz, 2H), 2.02 (s, 0.5H), 1.98 (s, 0.5H), 1.90 (br m, 2H), 1.6 (br m, 4H), 1.4 (br m, 20H), 0.82 (t, J= 7.5 Hz, 3H); BC NMR (75 MHz, CDCb) b 173.1, 170.0, 169.6, 132.2, 117.8, 89.9, 89.4, 72.6, 72.5, 64.7, 33.9, 31.6,30.6,29.6,29.4,29.0,28.9,28.87,28.8,28.72, 28.68, 25.7, 25.4, 25.1, 24.6, 24.3, 436 22.4,20.6,20.5, 13.9; IR (KBr) v 3086, 2929, 2857, 1743, 1649, 1555, 1465, 1375, 1226, 1175, 11 08, 989, 928, 855, 724 em-I. Compound 14. Acetylated intermediate 13 (1.5 g) was combined with NaZC03 (0.5 eq.) and benzene (60 mL) in a flask connected to a Dean-Stark trap and reflux condenser. The solution was heated to 90°C for 24 h ensuring azeotropic removal of HzO, at which time the solution was cooled to rt and partitioned with satd. NH4CI and EtzO. The aqueous layer was extracted 3 x EhO, and the combined organic layer washed with HzO and brine. The organic layer was dried over MgS04, the solvent removed under vacuum, and the desired product 14 purified by column chromatography (5% EtOAc in hexanes) as a faintly yellow liquid in 74% yield: IH NMR (300 MHz, CDC!)) b 7.05 (t, J = 7.8 Hz, 1H), 5.88 (m, IH), 5.22 (m, 2H), 4.56 (d, J= 9.6 Hz, 2H), 2.55 (t, J= 7.5 Hz, 2H), 2.31 (t, J= 7.5 Hz, 2H), 2.20 (q, J = 7.5 Hz, 2H), 1.6 (br m, 2H), 1.45 (br m, 4H), 1.3 (br m, 16H), 0.82 (t, J= 7.5 Hz, 3H); l3C NMR (75 MHz, CDC!)) b 173.2, 151.8, 136.1, 132.2, 117.9,64.8,34.0,31.7,29.1, 29.0,28.9,28.8,28.3,27.8,26.2,24.7,22.5, 14.0; IR (KBr) v 2928,2857, 1739, 1667, 1521, 1459, 1336, 1171,989,928, 732 em-I. Compound 2. An oven-dried flask was charged with THF (15 mL), 98% formic acid (0.05 mL, 1.3 mmol), and allyl ester 14 (0.052 mmol). The solution was purged with Nz and Pd(PPh3)4 (5 mol%, dry) added. The solution was purged for 10 min. with Nz and then immediately immersed in an oil bath at 80°C. The solution was refluxed under Nz for 24 h, then cooled to rt and solvents removed under vacuum. The desired 437 product was purified by column chromatography (l% AcOH, 12% EtOAc in hexanes) in 95% yield: IH NMR (300 MHz, CDCh) {) 7.05 (t, J= 7.8 Hz, IH), 2.59 (t, J= 7.5 Hz, 2H), 2.38 (t, J= 7.5 Hz, 2H), 2.22 (q, J= 7.2 Hz, 2H), 1.6 (br m, 2H), 1.45 (br m, 4H), 1.3 (br m, 16H), 0.82 (t, J= 7.5 Hz, 3H); B C NMR (75 MHz, CDCh) {) 180.4, 151.9, 136.2, 33.9,31.7,29.2,29.1,29.0,28.9,28.8,28.4,27.9,27.8, 26.3, 24.5, 22.6, 14.0; IR (KBr) v 3500-2500, 2927, 2856, 1709, 1666, 1519, 1462, 1413, 1336, 1114,913,854, 733 cm- 1; HRMS for C1sH34N04, calcd. 328.24878; found 328.24826 Compound 16. Ph2Se2 (0.106 g, 0.68 mmol) was dissolved in absolute ethanol (10 mL), to which was slowly added NaBH4(0.026 g, 0.68 mmol). The solution was stirred under N2 at rt until it turned colorless. Nitroolefin 7 (0.223 g, 0.68 mmol) was then added and solution stirred at rt for 1 h, at which point the mixture was cooled to -78 °c. Acetic acid (0.04 mL, 0.68 mmol) was then added and the solution kept at -78°C for 1 h, whereupon the flask was warmed to rt. Water (10 mL) was then added, ethanol removed under reduced pressure, and the aqueous solution extracted three times with EtOAc. The collected organic layer was dried over Na2S04 and solvent removed under reduced pressure. The crude intermediate was then dissolved in CH2Ch (5 mL) and THF (5 mL), the solution cooled to 0 °c, and 30% H202 (0.07 mL, 0.68 mmol) added slowly. Stirring at 0 °c continued for 10 min. after which the flask was warmed to rt, H20 (10 mL) was added, and CH2Ch and THF were removed under vacuum. The remaining solution was then extracted three times with Et20 and the combined organic layer washed with satd. NaHC03. The organic layer was then dried over Na2S04 and 438 solvent removed under reduced pressure. A mixture of isomers was obtained in 76% yield (0.169g) as a pale yellow waxy solid. IH NMR of the crude product showed (Z) isomer 85%. Compound 12 was further purified by column chromatography (1 % MeOH in CHCh): I H NMR (300 MHz, CDCh) [) 5.65 (t, J= 7.5 Hz, 1H), 2.49 (t, J= 6.9 Hz, 2H), 2.33 (m, 4H), 1.62 (br m, 2H), 1.45 (br m, 4H), 1.3 (br m, 16H), 0.87 (t, J = 6.6 Hz, 3H); B C NMR (75 MHz, CDCh) [) 180.0, 151.4, 131.5,34.0,32.7,31.8,29.1,28.9,28.86, 28.8,28.7,28.2,27.2,24.5,22.6, 14.1; IR (KBr) v 3500-2500, 2928,2857, 1709, 1551, 1522, 1465, 1340, 1285,939,859, 724 cm- I . oo-Dodecalactone (20). A flask was charged with cyc1ododecanone (2.0 g, 0.011 mol), m-chloroperoxybenzoic acid (4.2 g, 0.021 mol), and dry CHCh (25 mL), and heated at reflux for 48 h. Absence of peroxide was then confirmed by KI/starch test and the solution cooled to 0 °c. Precipitated m-ch10robenzoic acid was removed by filtration and solvent reduced under vacuum. The crude product was taken up in EhO and washed with K2C03 followed by brine. Lactone 20 was purified by column chromatography (5% EtOAc in hexanes) as a colorless oil (2.03 g, 93%) lH NMR (300 MHz, CDCh) [) 4.15 (t, J = 5.4 Hz, 2H), 2.38 (m, 2H), 1.65 (br m, 4H), 1.36 (br m, 14H). 439 Compound 21. Lactone 20 (2.03 g, 0.010 mol) was dissolved in EtOH (50 mL) to which was then added KOH (1.5 eq. in 20). The solution was refluxed for 3 h, after which H20 (50 mL) was added and the solution cooled to rt. 5N H2S04 was then added slowly until pH = 4, after which the resulting precipitate was collected by filtration, washed 3 x H20, and dried under vacuum to give crude product 21 as a white solid which was used without further purification (1.77 g, 80%). Compound 22. Acid intermediate 21 (1.0 g, 4.6 mmol) was combined with H20 (7 mL) and NaHC03 (0.39 g, 4.6 mmol) in a flask and stirred until complete dissolution of starting material. A prepared solution ofCH2Ch (7 mL), Aliquat 336 (1.84 g, 4.6 mmol), and allyl bromide (0.6 g, 4.6 mmol) was then added to the aqueous solution and stirred at rt for 72 h. The mixture was then extracted three times with CH2Ch, dried over MgS04, and solvents removed under reduced pressure. The desired product was purified by column chromatography (5% EtOAc in hexanes) giving 22 as a white solid (0.92 g, 78%): IH NMR (300 MHz, CDC!]) [) 5.85 (m, 1H), 5.22 (m, 2H), 4.58 (d, J = 9.6 Hz, 2H), 3.62 (t, J= 6.3 Hz, 2H), 2.3 (t, J= 7.2 Hz, 2H), 1.6 (br m, 4H), 1.3 (br m, 14H); BC NMR (75 MHz, CDC!]) [) 173.8, 132.5, 118.3,65.1,63.0,34.4,33.0,29.7,29.6,29.4, 29.3,26.0,25.1;IR(KBr)v3357,2927,2852, 1737, 1649, 1463, 1176, 1108, 1062,991, 925 cm-I. 440 Compound 23. DMSO (0.6 mL, 8.5 mmol) in CH2Ch (4 mL) was added dropwise to a flask containing oxalyl chloride (0.34 mL, 4.3 mmol) in CH2Ch (24 mL) at -60 DC under argon. The reaction was stirred for 5 min., after which alcohol 15 (0.58 g, 2.3 mmol) dissolved in CH2Ch (10 mL) was added. The solution was warmed to -50 DC and stirred for an additional 20 min., then cooled to -70 DC and Et3N (3 mL, dry) added slowly. After 20 min., H20 (10 mL) was added and the solution allowed to warm to rt. The organic layer was separated, the aqueous layer extracted three times with CH2Ch, and the combined organic layer washed 2 x brine and dried over MgS04. Solvents were removed under reduced pressure and the desired aldehyde 23 purified by column chromatography (5% EtOAc in hexanes) in 95% yield (0.55 g): IH NMR (300 MHz, CDCb) f) 9.76 (t, J= 1.8 Hz, 1H), 5.88 (m, 1H), 5.22 (m, 2H), 4.55 (d, J= 9.6 Hz, 2H), 2.42 (t, J= 7.5 Hz, 2H), 2.33 (t, J= 7.5 Hz, 2H), 1.60 (br m, 4H), 1.32 (br m, 12H); BC NMR (75 MHz, CDCb) f) 202.9, 173.5, 132.3, 118.0,64.9, 43.9,34.2,29.3,29.2,29.1,24.9,22.0; IR (KBr) v 2934, 2858, 2720, 1736, 1649, 1458, 1418,1378,1174,1105,991,933 em-I. Compound 24. The condensation of 1-nitrohexane with aldehyde 23 by methods identical to those in the preparation of nitroaldol product 12 gave 24 in 95% yield: IH NMR (300 MHz, CDCb) f) 5.88 (m, IH), 5.22 (m, 2H), 4.60 (d, J= 9.6 Hz, 2H), 4.45 (m, 1H), 3.95 (m, IH), 2.40 (t,J= 7.5 Hz, 2H), 2.10 (br m, 2H), 1.80 (br m, 2H), 1.65 (br m, 2H), 1.4 (br m, 20H), 0.92 (t, J= 7.5 Hz, 3H); BC NMR (75 MHz, CDCb) f) 173.4,132.0,117.7,93.0,92.3,72.1,71.9,64.7,34.0,33.1, 33.0, 30.9, 30.8, 441 30.0,29.2,29.1,29.06,29.0,28.8,28.1,25.4,25.3, 25.1, 25.0, 24.7, 22.1, 13.6; IR (KBr) v 3481, 2927, 2856, 1736, 1649, 1549, 1458, 1379, 1175, 1111, 989, 931, 842, 733 em-I. Compound 25. Compound 25 was acetylated in an identical manner to the formation of 13, giving intermediate 25 in 99% yield I H NMR (300 MHz, CDC!)) 6 5.88 (m, 1H), 5.22 (m, 2H), 5.15 (m, 1H), 4.58 (m, 1H), 4.56 (d, J= 9.6 Hz, 2H), 2.25 (t, J= 7.5 Hz, 2H), 2.02 (s, 0.5H), 1.98 (s, 0.5H), 1.90 (br m, 2H), 1.6 (br m, 4H), 1.4 (br m, 20H), 0.82 (t, J = 7.5 Hz, 3H); BC NMR (75 MHz, CDC!)) 6 173.3, 170.1, 169.7, 132.3, 117.9,90.0,89.5, 72.8, 72.7, 64.8, 34.1, 31.0,30.9,30.7,29.7,29.6,29.3,29.2,29.1,29.0,28.8, 25.4, 25.2, 25.1, 24.8, 24.4, 22.1,20.7,20.6,13.7; IR (KBr) v 3086, 2929, 2857,1744,1649,1554,1462,1373, 1228, 1173, 1111, 1023, 990, 931, 842, 732 em-I. 442 BIBLIOGRAPHY Chapter I (1) Faraday, M. Phil. Trans. Royal Soc. London 1825, 115,440-466. (2) Stock, A.; Pohland, E. Ber. Dtsch. Chern. Ges. 1926,59,2210-2215. (3) Ulrich, G.; Ziessel, R.; Harriman, A. Angew. Chern. Int. Ed 2008,47, 1184-1201. (4) Loudet, A.; Burgess, K. Chern. Rev. 2007,107,4891-4932. (5) Bosdet, M. 1. D.; Piers, W. E. Can. 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