Photoinduced electron transfer in arranged media

Abstract

Although the transfer of an electron is an elementary chemical event, its consequence on the reactivity of the reagents involved in the exchange is profound, inverting the normal electron demand of each participant. Photoinduced electron transfer provides a sensitive probe for excited state dynamics and the influence of the environment of the excited molecule on the course of both the primary photoinduced electron exchange and on the all-important thermal back electron transfer between members of the electron donor-acceptor pair. A non-homogeneous medium provides a unique arena in which sensitive environmental effects can be probed and altered. As practical applications of photoinduced electron transfer come increasingly to the fore, exploitation of these arranged media in providing order at the molecular level will be ever more important. The lessons to be learned from thorough studies of such photoinduced electron transfer reactions will be of significance not only to physical, organic, and inorganic photochemists but also to materials scientists and engineers. This article has provided but a brief summary of how self-assembled systems can be used, either alone or in conjunction with a molecular photosensitizer or semiconductor photocatalyst, as vehicles to enhance supramolecular interactions and observable chemistry. Many fascinating questions still remain.