This award in the Inorganic, Bioinorganic, and Organometallic Program provides continued support to Dr. Louis H. Pignolet of the Chemistry Department, University of Minnesota, for the investigation of mixed metal cluster compounds containing gold, platinum, and palladium. Pignolet will synthesize additional cluster molecules that are larger, contain a wider variety of metals, and use less bulky phosphine ligands. Recently, Pignolet has observed that hydrogen molecules can equilibrate with deuterium molecules on the surface of these clusters. He wishes to explore the mechanism of this interaction and characterize the species involved. He would also study the catalytic activity of these clusters upon hydrogenation under both homogeneous and heterogeneous conditions. The catalyst systems would be characterized using TEM, XPS, chemisorption and other surface methods. %%% Many industrial catalysts contain a mixture of metals, and it is speculated that the effectiveness of these catalysts depends on a synergistic interaction between the various metals. Mixed metal clusters, containing eight to twenty metal atoms, have been postulated as useful model compounds for understanding the details of such catalytic activity. In this project, Pignolet will make larger and more varied clusters and reduce the size of the stabilizing phosphine groups attached to the metals so as to enhance the cluster's catalytic effectiveness. The catalytic behavior of the clusters will be investigated, particularly for hydrogenation catalysis, and both free and alumina-supported clusters will be studied. The results could provide increased understanding of the factors affecting the reactivity of catalysts.