Solvent-Polarity Tuning Excited-State Charge Coupled Proton-Transfer Reaction in <i>p</i><i>-N</i>,<i>N</i>-Ditolylaminosalicylaldehydes
作者:Pi-Tai Chou、Wei-Shan Yu、Yi-Ming Cheng、Shih-Chieh Pu、Yueh-Chi Yu、Yu-Chung Lin、Huang、Chao-Tsen Chen
DOI:10.1021/jp048415k
日期:2004.8.1
with a common population decay rate of 360 ps -1 . The normal emission exhibits drastic solvent-polarity dependence and has been concluded to originate from a chargetransfer species incorporating excited-state intramolecular charge transfer from ditolylamine to carbonyl oxygen. In dipolar solvents, competitive rates between ESIPT and solvent relaxation were observed, and the solvated charge-transfer state
通过发光光谱和飞秒动力学已经获得了对 pN,N-二甲苯基氨基水杨醛 (Ia) 中电荷与质子转移的激发行为的详细了解。在环己烷中,随着激发态分子内质子转移 (ESIPT) 的超快速率 (2.0 10 12 s -1 ),在正常 (N*) 和互变异构体激发态 (T*) 之间发生快速平衡,导致双荧光最大化分别在 450 和 540 nm 处,常见的群体衰减率为 360 ps -1 。正常发射表现出强烈的溶剂极性依赖性,并且已经得出结论,其起源于结合了从二甲苯胺到羰基氧的激发态分子内电荷转移的电荷转移物质。在偶极溶剂中,观察到 ESIPT 和溶剂弛豫之间的竞争速率,并且溶剂化的电荷转移状态在热力学上更有利,因此发生了 T* f N* 反向质子转移。Ia 的甲氧基衍生物以及其他相关类似物的相应实验提供了补充支持。结果揭示了详细的质子/电荷转移耦合动力学以及早期时域相关的溶剂弛豫动力学。