This project, supported in the Analytical and Surface Chemistry Program, focusses on the study of the role of electronic conjugation in promoting long-range electron transfer between a metal electrode and redox site located at a known distance from the electrode surface. Key to this work will be the use of alkyl thiols with pendant ferrocene groups to form self assembled monolayers on metal electrode surfaces. Phenylene and naphthalene moieties will be substituted at various known positions along the alkyl chain to vary the position of electronic conjugation. During this three year continuing grant Professor Creager and his research students at Clemson University will synthesize these compounds, characterize their structure upon formation of self assembled monolayers, and study their electron transfer properties using ellipsometry, reflection-absorption infrared spectroscopy, potential step chronoamperometry, fast-scan cyclic voltammetry, and fast electrochemical impedance spectroscopy. This project will contribute to the understanding of the function of biological electron transfer reactions, test the theory and experimental probes of fast electron transfer reactions that occur over long distances, and determine the relative contributions of electronic coupling and nuclear dynamics in controlling the kinetics of these processes. Many biological processes, electronic materials, and nanoscale catalytic structures require electron transfer reactions that occur in short periods of time over long distances. The trapping, conversion, and subsequent efficient use of energy can become practical when long range electron transfer processes are fast. This project will involve research students at Clemson University in the determination of the molecular level requirements for fast electron transfer reactions. Very fast electrochemical and spectroscopic measurements will be used to test and further develop modern theories on the dependence of electron transfer rates on distance.
