CAREER: SusChEM: Metal-Metal Bonds as Active Sites in Catalysis

Purdue University, West Lafayette IN

Investigators

Abstract

In this project supported by the Chemical Catalysis Program of the Chemistry Division, Professor Christopher Uyeda of the Department of Chemistry at Purdue University studies molecular transition metal catalysts containing dinuclear active sites. In nature highly complex systems that contain two or more metals carry out electron transfer transformations that are central to biosynthesis and energy management. In contrast, molecular catalysts that are currently used to promote related reactions have comparatively simple structures, most commonly containing just a single metal center. This single metal must mediate all of the bond-breaking and forming events. In principle, new classes of catalysts that contain multiple metals could exhibit metal cooperativity as seen in the naturally occurring systems. These could exhibit unique properties as compared to their more well-established mononuclear counterparts. This research aims to develop the fundamental principles underlying the design of robust and efficient synthetic multinuclear catalysts. The project also contains an educational component that will introduce high school and beginning undergraduate students to catalysis research. Providing such research opportunities at Purdue positively impacts the engagement of high school students in cutting-edge research. This research focuses on the development of new redox-active ligand architectures that support metal-metal bonds of defined composition. By capitalizing on ligand-centered redox couples, the resulting dinuclear complexes are capable of engaging organic substrates in many of the elementary two-electron processes (e.g. oxidative additions and reductive eliminations) that form the basis for catalytic transformations. An overarching goal of this project is to connect the electronic features of metal-metal bonds to their activity and selectivity in catalysis. As such, detailed mechanistic insights into these systems are sought by (1) developing electronic structure models through a combination of experiment and theory, (2) characterizing plausible catalytic intermediates, (3) studying catalytic processes using reaction kinetics and other physical organic techniques, and (4) conducting well-controlled comparative studies between mononuclear and dinuclear catalysts. These activities are integrated with an educational component that focuses on providing opportunities for young students, including local high school students, to engage in the catalysis research being carried out in university labs.