Functional Architectures for Electron Transfer in Solution and on Electrodes

Brown University, Providence RI

Investigators

Abstract

Professor Matthew B. Zimmt, of the Department of Chemistry at Brown University, is supported by the Organic and Macromolecular Chemistry Program for his studies of functional architectures for electron transfer in solution and at electrodes. A molecular scaffold will hold an electron donor and acceptor at a fixed distance and orientation without providing significant electronic coupling. Function will be introduced into this "test bridge" by attaching materials of interest to the scaffold, directly between the donor and acceptor. The donor/acceptor coupling provided by these molecular "test elements" will be determined through measurement and analysis of photoinduced electron transfer rate constants. A variety of test elements, representing structures found in biological and technological electron transfer systems, will be examined. Analogous introduction of function at electrode surfaces will also be explored, through the design, synthesis, and analysis of molecules which bind specifically to electrode surfaces. Electron transfer events occur in many important processes in chemistry and biology as well as in technological applications. Beyond their ubiquity, electron transfer reactions are of fundamental interest for their unique structural, thermodynamic, and medium dependence. The nature of the material lying between the electron donor and the electron acceptor exerts a considerable influence on the dynamics of the electron transfer event. The nuclear and electronic structures of the intervening material determine the nature of the transfer event, which may involve a hop into bound states of the material (conduction) or tunneling through virtual states of the material. By designing materials whose structure is susceptible to specific external stimuli and with the support of the Organic and Macromolecular Chemistry Program, Professor Matthew B. Zimmt, of the Department of Chemistry at Brown University, is exploring the possibility of rationally controlling the nature and dynamics of electron transfer processes.