This award in the Inorganic, Bioinorganic, and Organometallic Program will support research on the thermodynamics of organometallic reactions by Dr. Carl D. Hoff of the Chemistry Department, University of Miami. Although Hoff will investigate a wide variety of reactions, of particular interest are reactions of molybdenum sulfur complexes. These complexes are chosen for study because of their involvement in hydrodesulfurization catalysis, which effects the removal of sulfur from fuels, and nitrogen fixation in plants. Oxidative addition of hydrogen, hydrogen sulfide, thiols, and disulfides to molybdenum will be studied. The enthalpies of binding of various sulfur-containing species--thioethers, thiols, hydrogen sulfide, thiophene, disulfides, metallothiolates, and sulfur dioxide--to molybdenum will also be determined. %%% Dr. Hoff will investigate the energetics of molybdenum-sulfur bonds. The results will be of wide interest because little fundamental data concerning the thermodynamics of metal-sulfur bonds is currently available. Sulfur can bond to metals in a variety of bonding modes (single, multiple, bridging) and the strength of these bonds is influenced by the oxidation state of the metal and the presence of other groups around the metal. Understanding the influence of these factors for the molybdenum case could contribute to a better understanding and control of the catalytic processes of hydrodesulfurization and nitrogen fixation.
