Femtosecond Dynamics of Electron Transfer Reaction in Double Metal Complex Crystals

1.用飞秒激光光解技术研究了氧钛(IV)-酞菁(OTiPc)_n各种薄晶的光激发过程。瞬时吸收光谱的快速变化表明，β-OTiPc的部分激子在1ps内转变为单电子氧化物种(OTiPc)n^+，然后在20ps内空穴消失。大部分基态在50ps内恢复。α-OTiPc向(OTiPc)_n^+的转化不太明显。还测定了OTiPc晶体的量子产率和荧光寿命。来自α-OTiPc的峰值为10,420 cm~(-1)~(-1)的荧光显示出一个35-65ps的主要弛豫激子和一个100-424ps的次弛豫激子的双指数衰减。77K时短寿命荧光初始强度的增加表明，弛豫激子是298K时α-OTiPc激发的次要产物。光激发形成的载流子似乎比向RELA…的内部转换快得多更刺激的刺激。用不同反离子测定了[Os_xRu_&lt；1-x&gt；(Bpy)_3]X_2晶体中激发能转移和跃迁的距离相关速率常数。用蒙特卡罗方法分析和模拟了掺Os(II)的[Ru(Bpy)_3]X_2晶体中发射的非线性衰减。通过电子交换类型的分子相互作用是^3MLCT(Ru)在近距离向Os^&lt；2+&gt；的能量转移和^3MLCT(Ru)向最近邻跃迁的主要方式。测定了不同距离下向Os^&lt；2+和Gt；的能量转移和跳跃的速率常数。与参考值相比，电子交换作用的距离衰减因子(12.5 nm^&lt；-1&gt；)较小。纯晶体的时间分辨吸收光谱表明，T-T湮没产生了单电子转移产物。经计算，[Ru(Bpy)_3](PF_6)_2整晶中的电子转移速率大于5×10~(-1)~(-1)~(-1)~(-1)。较少

1. Photoprimary processes of various thin crystals of oxotitanium (IV) phthalocyanine (OTiPc)_n revealed by femtosecond laser photolysis. A rapid change of the transient absorption spectrum showed that a part of the exciton of β-OTiPc was in 1 ps converted to an one-electron oxidized species, (OTiPc)_n^+, then the hole disappeared in 20 ps. Most of the ground-state was recovered within 50 ps. The conversion to (OTiPc)_n^+ was less clear for α-OTiPc. Quantum yields and lifetimes of fluorescence for the crystals of OTiPc were also determined. A fluorescence with a peak at 10,420cm^<-1> from α-OTiPc exhibited biexponential decay of a major relaxed exciton with 35-65 ps and a minor relaxed exciton with 100-424 ps. An increase in the initial intensity of the short-lived fluorescence at 77 K indicates that the relaxed exciton is a minor product of the excitation of α-OTiPc at 298 K.A charge-carrier formation by photo-excitation seems to be much faster than the internal conversion to the rela … More xed exciton.2. Determination of distance-dependent rate-constants of excitation energy transfer and hopping in the crystalline solids of [Os_xRu_<1-x>(bpy)_3]X_2 with various counter ions. Non-linear decays of the emission in the crystals of [Ru(bpy)_3]X_2 doped with Os(II) have been analyzed and simulated by a Monte Carlo method. Molecular interaction via electron exchange type is predominant for the energy transfer of ^3MLCT(Ru) to Os^<2+> in the close proximity and for the hopping of ^3MLCT(Ru) to the nearest neighbor. The rate constants for the energy transfer to Os^<2+> and hopping were determined at various distances. A distance attenuation factor (12.5 nm^<-1>) obtained for the electronic exchange interaction was small compared with reference values.Time-resolved absorption spectroscopy for the neat crystal revealed that T-T annihilation produced the one-electron transferred products. Rate of electron transfer between ^3MLCT in the neat crystal of [Ru(bpy)_3](PF_6)_2 was estimated to be more than 5x10^<10>s^<-1>. Less