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

研究了配位组装的特殊卟啉配体在捕光天线、光诱导电子转移、光伏电池和双光子吸收体系中的应用。为了构建稳定的大环卟啉体系，发展了超分子方法和随后的复分解连接。用超快时间分辨光谱技术估算了卟啉大环的激发能跳跃（EEH）速率为1/（tens ps）。EEH时间常数比荧光寿命短得多，说明激发能可以长时间储存在大环中。利用超快激光光解研究了含电子受体和/或电子供体的特殊电子对的光诱导电子转移。由于其重组能小，特殊的电子对部分对于加速电荷分离和减速电荷重组是重要的。在ITO电极上制备了二氧化钛修饰的光伏电池，并对修饰电极进行了表征，发现修饰电极上的芳基膦酸基团具有良好的性能。构建了一种大环卟啉环与三吡啶配体的超分子复合物，作为捕光配合物I-反应中心复合物的模拟物。合成了一种由两个咪唑基酞菁取代卟啉的配合物。观察到吸收光谱中Q带的分裂和单电子氧化态的电荷离域。合成了具有极强双光子吸收的乙炔连接卟啉。这对光动力学治疗、抗癌药物的深部工作和三维光学数据存储等方面都有重要意义。

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.