9307750 Feher This award in the Inorganic, Bioinorganic, and Organometallic Chemistry Program supports research on silica-supported catalysts by Dr. Frank J. Feher of the Chemistry Department, University of California at Irvine. Three projects involving metallasilsesquioxanes will be pursued. The reactivity of molybdenum, tungsten, and rhenium-containing silsesquioxanes as olefin metathesis catalysts will be investigated, with particular emphasis on determining the effect of varying the M-O-Si bond angle. The chemistry of platinum group metals in highly siliceous environments will be compared to their behavior in more traditional ligand environments. New surface-modified silicas and silica-supported catalysts will be prepared to test the results of model studies in solution with the chemistry of heterogeneous catalysts. %%% Because silica (sand) is an amorphous insoluble material, it is difficult to study. Incompletely-condensed clusters of silicon and oxygen, called silsesquioxanes, are used here to mimic the hydroxylated surfaces of silica. In catalytic applications, in which silica is used as a support material for metals, reactions at the surface are important in the catalytic activity. An advantage of the silsesquioxanes is that they can be dissolved in many common organic solvents, thus allowing detailed studies using many of the powerful analytical techniques used to study molecules in solution. In this project, reactions which model surface reactions of silica and silica-supported catalysts will be carried out and the insights obtained will be tested on new heterogeneous catalysts. ***
