Author

Ryan J. Key

Date of Award

Spring 2019

Document Type

Open Access Dissertation

Department

Chemistry and Biochemistry

First Advisor

Aaron K. Vannucci

Abstract

In this work, we have addressed some of the issues surrounding catalytic crosscoupling reactions by using a nickel terpyridine catalyst, [Ni(tpy)(py)(CH3CN)2](PF6)2 in the Buchwald-Hartwig amination reaction and a functionalized variant, [(2,2':6',2''- terpyridine-4'-benzoic acid)Ni(II)]Cl2 on SiO2, in Suzuki coupling. These processes are unique in the approaches taken to achieve reactivity. In the Buchwald-Hartwig amination reaction, we used photoredox dual catalytic methods to achieve a sustainable approach to generate secondary and tertiary amines. This report is unique in many ways; most importantly, this method uses N-centered radicals to generate new C-N bonds. This report is also the first report to show generation of secondary and tertiary amines in the same reaction scaffold. For the Suzuki reaction, we developed a heterogeneous nickel catalyst by immobilization of a nickel terpyridine analogue on a solid oxide support. By doing so, we created a recyclable catalyst that can operate up to five reactions before suffering deactivation. The approach is more effective than homogeneous reactions, as the catalyst is easily reclaimed and simplifies both purification and analysis. We further developed this process by immobilizing the molecular catalyst using Atomic Layer Deposition. This approach allows for a physical barrier to be added to the catalyst motif that increases practical stability. Indeed, the immobilization worked effectively, allowing more than six reactions without any catalyst deactivation in aqueous solvents. After immobilization, activity was observed towards heteroaryl substrates, a useful moiety in pharmaceutical drug targets.

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Chemistry Commons

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