CAS: A Rethinking of Borrowing Hydrogen: from Ligand Design to New Reactions and Mechanisms

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With the support of the Chemical Catalysis program in the Division of Chemistry, Keying Ding of Middle Tennessee State University will study catalytic reactions that result in the formation of carbon–carbon or carbon–heteroatom bonds. These reactions will be mediated by new earth-abundant metal catalytic systems that utilize the “borrowing hydrogen (BH)” pathway. This BH pathway is environmentally friendly and atom- and process-efficient in producing value-added chemicals while producing water as the sole byproduct. Structure-reactivity correlations will be studied in an effort to glean critical information on how these catalysts facilitate this chemistry at the molecular level. The results will be used to direct catalyst development toward new and challenging reactions. This project will offer research experiences for students at the interface of synthetic inorganic chemistry, organic chemistry, and catalysis. The educational activities include efforts to enhance the participation of undergraduate students from underserved groups and low-income or first-generation families, participation in a summer research camp, and the integration of the funded research into teaching laboratories. The broader impacts of the research and educational activities will assist in the creation of a more diverse and educated workforce in the chemical sciences.Dr. Keying Ding and her research team at Middle Tennessee State University will study new base-transition metal catalysts to address emerging challenges in catalytic reactions that utilize the “borrowing hydrogen” mechanistic pathway. A new family of bifunctional ligands that feature reactive pendant arms that potentially promote hydrogen transfer reactions via metal-ligand cooperativity, and that contain rigid ligand scaffolds to provide stability, will be synthesized and characterized. The catalytic activities of the base transition-metal complexes will be determined with a focus on (i) establishing an in-depth understanding of the BH catalytic process, (ii) eliminating the dependence on the use of excess strong base in the BH reactions, and (iii) improving the product selectivity. New concepts and insights on the use of earth-abundant metals in place of precious transition metals for BH and related transformations are expected to arise from these studies to help guide the development of future catalysts.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.