This award in the Inorganic, Bioinorganic, and Organometallic Program provides support for research by Dr. M. David Curtis of the Chemistry Department, University of Michigan, on the reactivity of model complexes for dehydrosulfurization (HDS) catalysts. Curtis will synthesize small cluster molecules consisting of two or three atoms of molybdenum, one to three atoms of a second metal, such as iron, cobalt, or nickel, and two to four atoms of sulfur. Their structural features will be examined and compared to their behavior in oxidation-reduction reactions. Of particular interest are reactions involving abstraction of sulfur from organic molecules, particularly allyl sulfides. Another reaction of interest involves olefins and hydrogen, since hydrogen is known to be involved in the desulfurization sequence. Electrochemical studies, synthesis of organic molecules by desulfurization, and surface characterization of clusters when supported on alumina will also be included. %%% Hydrodesulfurization (HDS) is an commercial process that is promoted by catalysts prepared from molybdenum, cobalt, and sulfur. It is used to remove sulfur from organic materials and is therefore important to enhancing air quality in industrial areas. In this project, compounds which are models of the industrial catalyst will be prepared in an effort to understand the reactions which occur and perhaps improve the effectivess of the catalyst.