TOWARD TRANSPARENT MOLECULAR WIRES - ELECTRON AND ENERGY-TRANSFER IN TRANSITION-METAL DERIVATIZED CONDUCTING POLYMERS

A great deal of research has concentrated on long range electron and e nergy transport in transition metal-based systems, including molecular donor-acceptor assemblies, electron and energy transfer cascades, den drimers, and derivatized polymer systems. In an effort to improve effi ciencies for electron and energy transport over large distances, sever al groups have now turned to conjugated systems. Several challenges ex ist to incorporating conducting materials/polymers in the study of pho toinduced electron and energy transfer: solubility and processibility of the materials, thermal stability and limitations on direct spectros copic characterization due to band gap absorptions. We have prepared a new series of conducting materials that provides for direct incorpora tion of chromophores and electrophores within the backbone of a conduc ting polymer. Energy transfer dynamics between conducting polymer brid ges and porphyrin or metal-to-ligand charge transfer (MLCT) chromophor es can be controlled through intermolecular interactions in solid vs s olution samples. We have also developed a methodology to incorporate t ransmissive benzothiophene-type polymers such as polyisothianaphthene (PITN) within a copolymer assembly. These new materials are now being used to investigate long range electronic coupling and have potential applications that range from artificial photosynthesis to light emitti ng diodes. (C) 1998 Elsevier Science S.A.