Fivefold Annulation of Corannulene as a Route Toward Carbon Nanotubes and Nanocones

Thesis advisor: Lawrence T. ScottCurved carbon-rich materials such as carbon nanotubes and carbon nanocones have unique mechanical strength, charge carrying ability and structure. Efficient syntheses to access these strained structures are required to obtain usable quantities of these materials in order to exploit their unique properties. This dissertation describes the recent efforts toward gaining access to these interesting structures using corannulene as the foundation for the curvature. Chapter 2 offers a microwave assisted tandem Suzuki-Heck-type coupling of peri-dichloroacenaphthene with various aryl boronic acids. This allows for the formation of strained unsaturated five-membered rings in a single transformation. The extension of this methodology to peri-chloroacenaphthylboronic acids and aryl halides was also investigated. Chapter 3 discusses efforts toward the total synthesis of a [10,10] carbon nanotube end-cap. The key step was optimized on bicorannulenyl and applied to 1,3,5,7,9-pentacorannulenylcorannulene. Preliminary Diels-Alder reactions have been successful with di-cyclopenta[def]phenanthro[3,3a,4,4a,5,6-cdefg;3',3a',4',4a',5',6'-nopqr]pentacene, suggesting that the C120H20 end-cap should also be reactive under similar conditions. Chapter 4 presents progress toward the total synthesis of a carbon nanocone with a single five-membered ring. The acid-catalyzed oxidative cyclization seems to effect a 1,2-aryl shift, preventing the desired six-membered ring cyclodehydrogenation. To render this rearrangement degenerate and thus irrelevant, 9-phenanthrylcorannulene was utilized to replace the problematic 1-naphthylcorannulene. Chapter 5 describes the collaboration between the Shenhar laboratory at The Hebrew University of Jerusalem and the Scott laboratory to form supramolecular polymers using corannulene derivatives. It had been shown that corannulene tetraanion can dimerize with lithium cations, so the limitations were probed with the following larger corannulene networks: p-dicorannulenylbenzene, 1,3,5-tricorannulenylbenzene and 1,3,5,7,9-pentacorannulenylcorannulene.Thesis (PhD) — Boston College, 2011.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Chemistry