This project, in the Inorganic, Bioinorganic and Organo- metallic Chemistry Program, will explore the redox properties of metal clusters, and the volumes of activation of intra- molecular cluster processes. Cluster compounds to be studied in the first area will contain carbon atoms as part of the core structure. Substituents on these carbon atoms will have pi-donor/acceptor properties that will serve to delocalize the unpaired electron density arising from electron transfer processes. This is expected to stabilize the redox products such that they can be characterized by conventional spectro- scopic techniques. In the second area, volumes of activation for intramolecular processes will be studied for several series of compounds, whose reactivity has already been studied by other methods, to see if this parameter can be used as a reliable measure of the nature of the transition state. This is particularly important for reactions that are first order in cluster where it is presently nearly impossible to determine whether metal-metal bond cleavage, bridge to terminal ligand conversion, etc. is involved in achieving the transition state for the reaction. The ultimate objective of these investi- gations is to determine the ways in which the properties of ligated metal clusters differ from those of small uncomplexed aggregates of metal atoms and to be able to selectively modify these properties by changing the number of atoms in the cluster and the nature of the ligating groups. %%% This project is aimed at understanding the fundamental chemistry of organometallic compounds that are composed of small numbers of metal atoms that are bonded together (in a cluster) and are surrounded by donor ligands. In some ways the chemistry of these compounds models that of catalytic reactions of molecules on the surfaces of small metal particles that are routinely used in industrial processes.
