Variation of the electrochemical transfer coefficient with potential
Variation of the electrochemical transfer coefficient with potential
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DOI：
10.1039/dc9827400057
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
J. Savéant;D. Tessier
中科院分区：
文献类型：
--
作者：
J. Savéant;D. Tessier
电化学电子转移速率常数已被确定为一系列简单的电子转移过程中的有机分子在介质中含有乙腈或二甲基甲酰胺和季铵盐作为支持电解质和使用汞作为电极材料的电极电位的函数。反应和实验条件的选择，以便处理外球过程，并尽量减少双层修正的幅度。采用卷积电位扫描伏安法和交流阻抗法获得了动力学数据。在这些条件下，观察到在所有情况下，电化学传递系数随着电极电位而变化，超出了实验误差。的变化幅度是相同的数量级的马库斯理论预测的外层电子转移。一个更复杂的反应，苯甲醛在乙醇中的还原，涉及二聚步骤后的初始电子转移也进行了研究。再次观察到传递系数的一定变化。在各种溶剂和官能团中观察到的这种行为，在电荷转移快速且主要由溶剂重组控制的情况下，在有机分子的还原中作为一般现象出现。
The electrochemical electron-transfer rate constant has been determined as a function of the electrode potential for a series of simple electron-transfer processes to organic molecules in media containing acetonitrile or dimethylformamide and a quaternary ammonium salt as supporting electrolyte and using mercury as the electrode material. The reactions and the experimental conditions were selected so as to deal with outer-sphere processes and to minimize the magnitude of double-layer corrections. Convolution potential-sweep voltammetry and the impedance method were used for obtaining the kinetic data. Under these conditions, the electrochemical transfer coefficient was observed, in all cases, to vary, beyond experimental error, with the electrode potential. The magnitude of the variation is of the same order of magnitude as that predicted by the Marcus theory of outer-sphere electron transfer. A more complex reaction, the reduction of benzaldehyde in ethanol, involving dimerization steps following the initial electron transfer was also investigated. A definite variation of the transfer coefficient was again observed. This behaviour, observed for various solvents and functional groups, appears as a general phenomenon in the reduction of organic molecules in the case where charge transfer is fast and mainly governed by solvent reorganization.