The Inorganic, Bioinorganic, and Organometallic Chemistry Program supports the efforts of Professor Kenneth M. Nicholas of the University of Oklahoma Norma Campus to test the hypothesis that efficient and selective homogeneous transition metal catalysts can be evolved by templating dynamic (equilibrating) metal complexes with substrate and transition state analogs. Three classes of important addition reactions will be studied: a) carboxyl ester and amide hydrolysis, b) ketone transfer hydrogenation, and c) [4+2] cycloadditions. Results from these studies may provide a deeper understanding of metal-centered reaction transition states, which could impact the design of both heterogeneous catalysts with commercial, energy-saving and environmental benefits, and the development of enzyme inhibitors with biological and health implications. The project will broaden the participation of underrepresented groups, including African and Native Americans, by actively recruiting researchers into an internship program at the Oklahoma School of Science and Mathematics and the Oklahoma University Minority Engineering Program.
The discovery and design of catalysts for chemical reactions is critical to the development of new, efficient and environmentally benign processes for the production of valuable chemical products. There were two primary aims of this project: 1) to evaluate the central hypothesis that coordination catalysts can be evolved by dynamic (equilibrium-controlled) templating with transition state analogs; and 2) to utilize dynamic templating to discover new, selective catalysts for two types of important reactions: a) carboxyl ester and amide hydrolysis; and b) cycloadditions. Targeted applications of this strategy for catalyst discovery included the kinetic resolution of alcohols and esters and the development of regioselective hetero-Diels-Alder reactions. The project team, consisting of three B.S. and two Ph. D. students, two postdoctoral fellows and the P.I., successfully met the project objectives through research studies with the following outcomes: 1) a proof-of-concept demonstration that the affinity of zinc-ligand compounds for transitions state analogs (TSAs) correlates with their catalytic activity; 2) that chiral (mirror-image) zinc-based compounds can be selected with chiral TSAs to catalyze the enantioselective (right vs. left-handed) hydrolysis reactions of esters- valuable for preparation of agrochemicals and pharmaceuticals; and 3) that the relative affinity of equilibrating copper-ligand compounds for product-like TSAs can be used to discover catalysts for selective cycloaddition reactions between unsaturated hydrocarbons- dienes, and nitrosoaromatic compounds. The results of these studies have been reported in several peer-reviewed scientific journals and at several regional and national scientific meetings.
