Photoinduced electron/energy transfer across molecular bridges in binuclear metal complexes

Molecular bridges that efficiently move charge between remote donor and acceptor sites can be thought of as molecular wires. Insight into the properties of molecular wires can be obtained by studying photoinduced electron transfer in covalently linked donor-bridge-acceptor systems. This article summarizes some of the recent progress in the study of such systems involving transition metal complexes as donor and acceptor units. Specific classes of molecular bridges are considered, namely, polyphenylene, and polyquinoxaline bridges. Basic questions are discussed, such as the transfer mechanisms, the associated distance and bridge structure dependence, and the interplay between energy and electron transfer.