This five year continuing grant is for the support of Professor Feher as a Presidential Young Investigator. The major project for which these funds will be used is aimed at understanding at the molecular level the way in which an important group of heterogeneous catalysts function. The major thrust of the research program is the development of new methods and strategies for modeling reaction processes that occur on silica-supported metal oxide catalysts. The model compounds which have been chosen, and some of which have been synthesized already, are large polyhedral siloxane ligands which approximate the coordination environments of surface catalytic sites. Current studies are focused on a new class of compounds called polyhedral oligometallasilsesquioxanes (POMSS), which are designed to model the chemistry of isolated metal atoms coordinated to three surface hydroxyl groups. A large number of examples of POMSS will be synthesized with different metals, the oxides of which are used as catalysts. Spectral data for these will be compared with data which have been reported from surface studies, both to test the validity of spectral assignments from actual surface studies and the validity of the compounds as models. Examination of the chemical reactivities of POMSS and studies of reaction mechanisms for these compounds are expected to provide a more detailed description of the reaction processes that can occur on a silica surface.
