Cycloparaphenylenes as Templates for the Growth of Homogenous Armchair Carbon Nanotubes
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Carbon nanotubes (CNTs) are among the most promising materials for next generation technology, displaying amazing physical and electronic properties. Unfortunately, the electronic properties of CNTs are highly dependent upon their molecular structure and diameter. This correlation between structure and property is exciting in that nanotubes are inherently tuneable; however, the lack of a scalable purification method and insufficient control over structure during synthesis is currently hampering industrial application. As a potential solution to this longstanding problem, [n]Cycloparaphenylenes ([n]CPPs), the smallest horizontal segment of an armchair CNT, hold great promise as seeds for the growth of homogenous batches of CNTs. First synthesized in 2009 by Jasti, the CPPs were themselves a great scientific achievement. In addition to their own interesting properties, it was put forth by the community that they might be viable seeds for the templated growth of homogenous armchair CNTs. However, we have concluded that in order to prove efficient in this context they must be pi-extended through traditional synthesis before use in growth. This work documents my research towards the utilization of these interesting molecules for that goal. This work begins in Chapter I with a discussion of growing a small molecule template into batches of homogenous CNTs, along with a review of the current state of the field. This segues into my research on the CPPs as potential templates, beginning with my development of a novel, divergent route to numerous CPPs in Chapter II. The highlights of this chapter are the synthesis of CPP, the smallest CPP synthesized at the time, and the larger quantities of CPPs this route affords, allowing research on these interesting molecules. Chapter III outlines the extension of this synthetic strategy towards aryl-substituted CPPs towards making pi-extended templates through a Scholl reaction. This work is continued in Chapter IV, an in-depth study of the Scholl reaction on these unique molecules. The work concludes in Chapter V with the beginnings of an experimental study of the Diels-Alder growth strategy on CPPs with curved pi-extended model fragments embedded in the CPP backbone. This dissertation contains previously published and unpublished coauthored work.