Heterogeneous rates of electron transfer. Application of cyclic voltammetric techniques to irreversible electrochemical processes
Heterogeneous rates of electron transfer. Application of cyclic voltammetric techniques to irreversible electrochemical processes
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DOI：
10.1021/ja00534a036
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发表时间：
1980-07
影响因子：
15
通讯作者：
R. J. Klingler;J. Kochi
中科院分区：
文献类型：
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作者：
R. J. Klingler;J. Kochi
在乙腈溶液中，各种均配烷基金属的不可逆循环伏安图中的阳极峰电位与它们在气相中测定的电离势/D呈显著的线性关系。各种瞬态电化学技术的应用证明，电极过程产生于一个完全不可逆的ECE序列，其中的峰值电位仅由非均相电子转移和扩散的动力学确定，不受任何后续化学反应的复杂性。结果表明，阳极峰电位ε n与电子转移活化自由能直接相关，ε p与ID的相关关系呈线性树能关系。非均相电子转移的机制被描述为一个外层过程，只依赖于单电子氧化的驱动力和独立的空间位阻效应的烷基金属。在直接比较的电化学过程与氧化的相同的烷基金属由一系列的聚（吡啶）铁（III）配合物在溶液中的密切关系的激活的复合物的异质性和均匀的电子转移强调。
The anodic peak potentials in the irreversible cyclic voltammograms of various homoleptic alkylmetals in acetonitrile show a striking linear correlation with their ionization potentials/D determinedin the gas phase. Application of various transient electrochemical techniques proves that the electrode process arises from a totally irreversible ECE sequence inwhich the peak potential is determined solely by the kinetics of heterogeneous electron transfer and diffusion—uncomplicated by any follow-up chemical reaction. As a result, the anodic peak potential£„can be directly related tothe activation free energy for electron transfer, and the correlation of£ p and ID represents a linear tree-energy relationship. The mechanism of heterogeneous electron transfer is described as an outer-sphere process, dependent only on the driving force for one-electron oxidation and independent of steric effects of the alkylmetal. The close relationship between the activated complexes for heterogeneous and homogeneous electron transfer is emphasized in a direct comparison of the electrochemical process with the oxidation of the same alkylmetals by a series of poly (pyridine) iron (III) complexes in solution.