Date of Award
Summer 7-28-2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Chemistry
First Advisor
Dian Wang
Second Advisor
Adam Fiedler
Third Advisor
Chae Yi
Abstract
Throughout the last several decades, photochemistry has received widespread research interest due to its mild conditions and its ability to generate highly reactive radical intermediates that demonstrate unprecedented reactivity, and selectivity. The vast majority of recent photochemistry literature utilize common Ir and Ru photosensitizers that have long-lived excited states. While such photosensitizers are efficient photooxidants and/or photoreductants, there has been an increase in research dedicated to developing earth-abundant transition metals as potential photocatalysts. Interestingly, Cu has demonstrated itself to be a successful candidate for photocatalysis. Many Cu-catalyzed light-driven processes that have been recently investigated operate through a different mechanism than the established photosensitizers. Instead of being limited to substrate activation, Cu photocatalysts have demonstrated that in addition to harnessing visible light, they are also involved in key bond-breaking and bond-forming steps in the mechanism. Further research of Cu photocatalytic mechanisms will likely lead to an enhanced understanding of the roles of Cu photocatalysts, and as a result these Cu photocatalysts can further be applied to other visible light driven organic reactions. Herein, this thesis presents three research projects dedicated to studying copper’s role in different visible-light-driven organic reactions. A developed Cu (II) system was able to successfully dechlorinate trichloroacetic acid to dichloroacetic acid through visible-light driven catalysis. Next, a catalytic method, which features Cu (I) photocatalysis, environmentally benign ascorbic acid as the hydrogen atom source and water/ethanol as the solvent, was further applied to the dehalogenation of a variety of halocarboxylic acids and amides. Finally, a method was developed to synthesize γ-lactams and γ-lactones through visible-light driven Cu (I) catalysis via [3+2] cycloaddition of α-chlorocarbonyl species and alkenes.