CBE Seminar - Bruce Gates
Thu, Sep 11 2014, 11:30am - 12:30pm
207 Koffolt Lab
140 W 19th Ave
Columbus, OH 43210
Molecular Metal Catalysts on Supports: Organometallic Chemistry Meets Surface Science
Bruce C. Gates
Department of Chemical Engineering and Materials Science
University of California, Davis
Advances in synthesis and characterization of essentially molecular metal complexes and clusters on supports are making a reality of catalyst design. We summarize work unraveling effects of the design variables of these site-isolated catalysts: the metal, metal nuclearity, support, and other ligands on the metal. The syntheses provide structurally simple, uniform species bonded to crystalline porous supports chosen for their uniformity, zeolites and MgO. The supports are ligands with electron-donor properties that influence reactivity and catalysis. The catalyst syntheses involve reactions of organometallic precursors with support surfaces; the precursors are M(L)2(acetylacetonate)1–2, with M = Ru, Rh, Ir, or Au and the ligands L = C2H4, CO, or CH3. Os3(CO)12 and Ir4(CO)12 serve as precursors of supported metal clusters, and some these are made by ship-in-a-bottle syntheses to trap them in zeolite cages. The methods of characterizing catalysts include IR, EXAFS, XANES, and NMR spectroscopies, atomic-resolution electron microscopy, and computations at the level of density functional theory. The data demonstrate high degrees of uniformity of supported species and determine their compositions and structures, including the ligands and the metal–support bonding and structure. Each of the catalyst design variables was varied independently to create families of catalysts, illustrated by (a) zeolite HY- and MgO-supported mononuclear and tetranuclear iridium and (b) isostructural rhodium and iridium complexes on these supports. The data provide examples resolving the roles of the catalyst design variables, placing the science on a foundation of organometallic chemistry linked with surface science. The approach is illustrated with a highly active and selective MgO-supported rhodium carbonyl dimer catalyst for hydrogenation of 1,3-butadiene to give butenes.
Bruce Gates studied chemical engineering at Berkeley (B.S., 1961) and the University of Washington (PhD, 1966) and with a Fulbright grant did postdoctoral research at the Ludwig Maximilians University of Munich. He worked for two years as a research engineer at Chevron Research Company and began as an assistant professor at the University of Delaware in 1969, becoming the H. Rodney Sharp Professor of Chemical Engineering and Professor of Chemistry. In 1992 he joined the University of California, Davis, where he is Distinguished Professor in the Department of Chemical Engineering and Materials Science. He has spent four sabbatical years at the Ludwig Maximilians University of Munich and was recently a guest professor at Hokkaido University.
Gates’s research is focused on catalysis, with an emphasis on essentially molecular metal complex and metal cluster catalysts anchored to solid surfaces and on catalytic conversion of biomass-derived compounds. He authored the textbook “Catalytic Chemistry” and co-authored “Chemistry of Catalytic Processes.” He edits the monograph Advances in Catalysis. He serves on the U.S. Department of Energy’s Basic Energy Sciences Advisory Board. He has been recognized with awards from the American Chemical Society, American Institute of Chemical Engineers, the North American Catalysis Society, and the Council for Chemical Research. He is a member of the U.S. National Academy of Engineering.