Professor William E. Geiger of the University of Vermont is supported by the Analytical and Surface Chemistry program to investigate electron transfer processes of organometallic compounds. Molecular structural rearrangements that accompany electron transfer reactions are being studied focusing on reversible making and breaking of metal-ligand and metal-metal bonds in transition metal organometallic complexes and geometric changes in highly electron rich, hypervalent metal-cyclopentadienyl compounds. The use of the non-coordinating fluoroarylborate (FAB) type anions as electrolyte is enabling the study of radical cation dimerizations. Metal-metal bond formation and complexities of ruthenocene chemistry are being targeted. The feasibility of replacing ferrocenyl tags with more thermally robust ruthenocenyl tags in sensors and other devices is under study. Following on the development of FAB-type anions, the preparation of large, highly lipophilic cations based on bicyclic and tricyclic tetraamines is being undertaken with the goal of advancing synthetic and mechanistic work that relies on reductive electrochemistry. Also being addressed is the use of cations of Rh and Ir compounds containing the hydrotris(pyrazolyl)borate ligand to probe the reversible cleavage of metal-ligand sigma bonds, a process which has important implications for catalysis.
Electron transfer reactions are ubiquitous in nature and play an important role in processes such as photosynthesis, metabolism, the production of energy from hydrogen and fossil fuels, the synthesis of drugs and specialty chemicals, and the operation of batteries and sensors. This project is providing fundamental understanding of the relationship between electron transfer and molecular level structural changes to guide developments in these areas.
