DYNAMIC SOLVENT EFFECT ON BETAINE-30 ELECTRON-TRANSFER KINETICS IN ALCOHOLS
DYNAMIC SOLVENT EFFECT ON BETAINE-30 ELECTRON-TRANSFER KINETICS IN ALCOHOLS
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DOI：
10.1021/j100011a024
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发表时间：
1995-03-16
影响因子：
--
通讯作者：
BARBARA, PF
中科院分区：
文献类型：
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作者：
REID, PJ;BARBARA, PF
本文首次采用飞秒泵浦-探测光谱技术研究了甜菜碱-SO（B-30）在极性非质子溶剂中的电子转移动力学。在醇中，B-30被认为具有多维溶剂配位，其组分对应于溶剂/溶质氢键。将观察到的背电子转移（b-ET）时间与步行者等人的唯象电子转移模型的预测进行比较，其先前已显示对极性非质子溶剂工作良好。这个模型失败的醇，大概是由于氢键相互作用。然而，如果模型被修改，包括一个快速的组成部分，对应于氢键的变化，它同意在一个大的温度范围内的线性醇。实验证据表明，新确定的溶剂坐标的组成部分应与溶剂/溶质氢键位移，而不是溶剂的惯性响应。新的实验结果在醇，结合以前的结果在极性，非质子溶剂，确认和扩大以前的结论，溶剂化动力学和振动效应是重要的电子转移动力学的B-30。
The electron-transfer kinetics of Betaine-SO (B-30), which have been widely studied in polar, aprotic solvents, are investigated for the first time in alcohols with femtosecond pump-probe spectroscopy. In alcohols, B-30 is believed to have a multidimensional solvent coordinate with components corresponding to solvent/solute hydrogen bonding. The observed back-electron transfer (b-ET) times are compared to predictions of the phenomenological electron-transfer model of Walker et al., which has previously been shown to work well for polar, aprotic solvents. This model fails for alcohols, presumably due to hydrogen-bonding interactions. However, if the model is modified to include a fast component of solvation corresponding to changes in hydrogen bonding, it agrees well for the linear alcohols over a large temperature range. Experimental evidence suggests that the newly identified component of the solvent coordinate should be associated with solvent/solute hydrogen-bonding displacements, rather than the inertial response of the solvent. The new experimental results in alcohols, combined with the previous results in polar, aprotic solvents, confirm and broaden the previous conclusion that both solvation dynamics and vibrational effects are important in the electron-transfer kinetics of B-30.