Elucidation of Dynamics of Electron Transfer Process in Condensed Phases

为了阐明分子内核位移和溶剂动力学对ET速率的影响，我们研究了下列给体-受体连接化合物的分子内ET过程：(1)考察了M(II)-Rh(III)(M=Ru和Os)双核配合物中距离、溶剂、温度和能隙对光诱导和反向ET速率的依赖关系。结果表明，Ru(II)双核配合物的高密度激光激发产生了双激发态，大的核位移是影响ET速率的主要因素。两个MLCT态之间发生了三重三重态的湮没，形成了电荷分离态[Ru(I)-Ru(III)]，产率为40%。(3)在Ru(II)-M(III)(M=Ru和Os)混价配合物中，观察到Ru-MLCT激发态的快速猝灭。得到的产物是混价异构体Ru(III)-Os(II)，它经过Back ET过程再现了基态。(4)用近红外激光脉冲激发混价配合物Ru(II)-M(III)(M=Ru和Os)中的MMCT带，观察到从光学产生的混价异构体向后的电子转移过程。然而，异构态的低量子产率(-0.2)表明大多数Franck-Condon态在松弛之前衰减到基态。(5)测量了氯化锌-卟啉二元体在不同溶剂中的电荷分离和电荷复合速率。电荷复合速率随溶剂的变化可以用当前的非绝热电子理论来很好地理解。分子内重组能为0.175 eV，电子相互作用能为14 meV。

To elucidate the effects of both intramolecular nuclear displacement and solvent dynamics on ET rates, intramolecular ET processes have been studied in the following donor-acceptor linked compounds.(1) The dependencies of distance, solvent, temperature, and energy gap on the photoinduced and back ET rates in M (II) -Rh (III) (M=Ru and Os) dinuclear complexes have been examined. It is concluded that the large nuclear displacement in the rhodium complexes dominantly affected the ET rates.(2) The high-density laser excitation of a Ru (II) dinuclear complex was used to produce a doubly excited state. A triplet-triplet annihilation between two MLCT states occurred to form a charge-separated state, [Ru (I) -Ru (III)], with 40% in a production yield. The distance dependence of the charge-separation and charge recombination have been examined.(3) Rapid quenching of an Ru-MLCT excited state in the mixed-valent complexes, Ru (II) -M (III) (M=Ru and Os), was observed. The resulting product was the mixed-valence isomer state, Ru (III) -Os (II), which underwent back ET process to reproduce the ground state. Energy gap and temperature dependence of these ET rates have been studied.(4) On the excitation of MMCT bands in mixed-valent complexes, Ru (II) -M (III) (M=Ru and Os), with a near-IR laser pulse, a back ET process from an optically generated mixed-valence isomer state was observed. However, the low quantum yield (-0.2) of the isomer state suggests that most of Franck-Condon states decayd to the ground state before they relaxd.(5) The charge-separation and charge-recombination rates in Zinc chlorin-porphrin dyads have been measured in a variety of solvent. The variation of the charge-recombination rates with solvent was well understood in terms of current nonadiabatic ET theory. The intramolecular reorganization energy was estimated 0.175eV and the electronic interaction energy was 14meV.