Construction of supramolecular light-harvesting antenna and photo-induced electron transfer systems by use of coordination-organized special pair of porphyrin

点击翻译按钮获取中文摘要

Light-harvesting antenna, photo-induced electron transfer, photo-voltaic cell, and two-photon absorption systems by use of coordination-organized special pair of porphyrins were investigated. To construct stable macrocyclic porphyrin systems, supramolecular methodology and following metathesis linking was developed. Excited energy hopping (EEH) rates of the porphyrin macrorings were estimated as 1/(tens ps) by ultra fast time-resolved spectroscopic techniques. The much shorter EEH time constants compared with fluorescence lifetime indicate that the excited energy can be stored in the macroring for a long period. Photo-induced electron transfer of special pair having electron acceptors and/or donors was also investigated by ultra fast laser photolysis. The special pair moiety is important for acceleration of charge separation and deceleration of charge recombination due to its small reorganization energy. Photo-voltaic cell was constructed on ITO electrode modified by TiO2 and special pairs, and arylphosphonic acid moiety attached to the special pair showed good performance. A supramolecular composite of macrocyclic porphyrin ring and tripyridyl ligand were constructed as a mimic of light-harvesting complex I-reaction center composite. Instead of porphyrin, a special pair composed of two imidazolylphthalocyanines was synthesized. Split of the Q-band in absorption spectrum and charge delocalization of one-electron oxidation state were observed. Acetylene-linked porphyrins having extremely strong two-photon absorption were synthesized. These can be useful for photodynamic therapy anti-cancer agents working at deep part and 3-dimetional optical data storage.