The Inorganic, Bioinorganic, and Organometallic Chemistry Program of the Chemistry Division is supporting the research of Professors Harry B. Gray and Jay R. Winkler, California Institute of Technology. This project aims to probe long-range electron transfer and the role of electron tunneling through materials such as proteins. Electron transfer of this type is extremely sensitive to the difference in energy between the bridge and those of the donor and acceptor. Tunneling-energy effects should be readily observable for electron transfer over distances greater than twenty Angstroms in systems where the potentials of the redox sites differ only marginally from those of the bridge sites. Oligoxylyene-bridged binuclear have been designed specifically to meet these criteria. Distance decay parameters will be extracted from correlations of electron transfer rates to the number of xylene units in the bridge.
Electron-transfer reactions are the simplest of chemical transformations in that no bonds are formed or broken as the electron migrates from the donor to the acceptor. When the redox partners are separated by long distances, the rate of electron transfer is mediated by the intervening medium. This research will study the effects of energy differences between electronic states in the bridge and those of the donor and acceptor metal ions.
