Substitution and Analysis of Additional Heteroatoms in 1,2λ5-Azaphosphinines
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Date
2024-12-19
Authors
McNeill, John
Journal Title
Journal ISSN
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Publisher
University of Oregon
Abstract
Azaphosphinines are, simply put, six-membered heterocycles containing one
nitrogen and one phosphorus atom. While garnering more attention in the last couple
decades, they are still decidedly understudied. This lack of research is primarily due to
the difficult and often intense reaction conditions required to synthesize them. This is
especially true for the azaphosphinine moiety’s early iterations. In the Haley and
Johnson groups we have found a facile synthetic pathway that allows us to circumvent
these issues. In this dissertation I will discuss not only a history of the azaphosphinine
functional group but also the results of my independent research. The main body of my
Ph.D. work is concerned with the substitution of additional heteroatoms into our
thoroughly studied azaphosphinines. These substitutions result in dramatic changes to
both the supramolecular and photophysical properties of the heterocycles. While most
of the work I will discuss is related to different orientations of pyrido-fused
azaphosphinines, I also include a study on the thionation of the ubiquitous phosphoryl
group.
Chapter I is a holistic review of azaphosphinines. I begin by discussing the
nomenclature and unusual electronic properties of these heterocycles before detailing a
chronological progression of the literature concerning the three isomers and both
valencies of the azaphosphinine functional group. In Chapter II I describe the synthesis
and unexpected tautomerization effects observed in pyrido[2,3-e]-1,2λ5-
azaphosphinines. Chapter III continues to explore the electronic effects of a pyrido fusion,
but in this case, we are now considering the internal charge transfer present in
pyrido[3,4-e]-1,2λ5-azaphosphinines. And lastly Chapter IV examines the thionating
effect of Lawesson’s Reagent on our heterocycles and the dramatic impacts this
transformation has on their photophysical properties.
This dissertation includes previously published co-authored material.
Description
Keywords
Heteroatom, Heterocycles, Nitrogen, Phosphorus, Pyridine, Supramolecular