Collaborative Research: CAS: Exploration and Development of High Performance Thiazolothiazole Photocatalysts for Innovating Light-Driven Organic Transformations

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With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Michael G. Walter at the University of North Carolina at Charlotte and Professor James M. Hanna at Winthrop University are designing new, low-cost, scalable, and high efficiency photocatalysts, scaffolds that harness light energy for performing chemical transformations. The overall goal is to advance more sustainable, carbon-based photocatalyst scaffolds that will reduce cost and overall environmental impact compared to traditional precious metal-based systems. The study includes the synthesis and study of new catalyst scaffolds, with the goal of advancing fundamental knowledge about how modifications affect reactivity. The new catalysts will then be studied in a variety of chemical transformations that currently rely on expensive-metal photocatalysts. The work will be built upon a new regional collaboration between UNC Charlotte and Winthrop University and will involve both undergraduate and graduate students from both research groups who will gain exposure to diverse and interdisciplinary activities across the practice of chemical research. In addition, the research components will be connected with the classroom teaching of the investigators, introducing photochemical science topics to a diverse group of graduate and undergraduate students. The investigators will continue their collaborations with local science museums, educators, and schools to develop and provide chemistry outreach programs to the Charlotte region.The goal of this research is to study and develop new thiazolo(5,4-d)thiazole (TTz) organic photoredox catalyst derivatives. TTzs are attractive photocatalyst materials due to their low-cost, single reaction step syntheses, non-halogenated, and high photochemically stable heterobicyclic core. TTz photocatalysts will address the need to develop scalable, high efficiency organic photocatalyst tools to drive a wide array of organic transformations. The team hypothesizes that the unique TTz photochemical properties enable new and improve upon existing transformations currently driven with expensive and toxic molecular transition-metal catalysts. Secondly, it is proposed that extended TTz photocatalyst materials will enable lower energy (e.g. red light) driven transformations while helping to tune redox characteristics for specific transformations. Preliminary studies have demonstrated the ability of a series of TTzs to drive reactions with much higher efficiencies than previously used transition metal photocatalysts. The collaborative team will further explore photocatalyst stability, reaction rates, and ability to drive a range of organic transformations. A library of new TTz photocatalyst derivatives will be developed with tunable light absorption properties and redox characteristics. Photochemical studies will be carried out to establish reaction quantum yields, and rates will be monitored using fluorescence and chromogenic TTz coloration changes. This collaborative research program will focus on photochemical efficiency metrics to help guide subsequent generations of TTz photocatalysts with a focus on optimizing performance and versatility. The materials produced by this project can benefit society by contributing to the development of a new series of photocatalyst materials that have the potential to improve synthetic efficiency and lower provide for more sustainable organic synthesis methodology.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.