Electrochemical Reduction of Quinones Interfacing Experiment and Theory for Defining Effective Radii of Redox Moieties
Electrochemical Reduction of Quinones Interfacing Experiment and Theory for Defining Effective Radii of Redox Moieties
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DOI：
10.1021/jp101730e
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发表时间：
2010-11-18
影响因子：
3.3
通讯作者：
Vullev, Valentine I.
中科院分区：
文献类型：
--
作者：
Bao, Duoduo;Ramu, Sangeetha;Vullev, Valentine I.
用循环伏安法研究了六种醌类化合物的还原电位与支持电解质浓度的关系。电解质浓度的增加导致溶液极性的增加，我们将观察到的还原电位的变化归因于醌及其阴离子的溶剂化能对介质极性的依赖性。使用Born溶剂化能方程的还原电势，对于醌类物质的有效半径产生了不可行的小值，即实验获得的有效半径比我们计算的醌类溶剂化腔的半径小多达4倍。醌类的非球形形状，沿着在其阴离子中不均匀的电荷密度分布，概括了这些氧化还原物质半径的实验值和理论值之间存在差异的根本原因。广义玻恩方法不将溶剂化物质视为单一球体，提供了解决这种差异的方法，并产生了相对接近测量值的有效半径
Using cyclic voltammetry, we examined the dependence of the reduction potentials of six quinones on the concentration of the supporting electrolyte An increase in the electrolyte concentration resulting in an increase in the solution polarity, caused positive shifts of the reduction potentials We ascribed the observed changes in the potentials to the dependence of the solvation energy of the quinones and their anions on the media polarity Analysis of the reduction potentials, using the Born solvation energy equation, yielded unfeasibly small values for the effective radii of the quinone species, that is the experimentally obtained effective radii were up to 4-fold smaller than the radii of the solvation cavities that we calculated for the quinones The nonspherical shapes of the quinones, along with the uneven charge density distribution in their anions, encompassed the underlying reasons for the discrepancies between the obtained experimental and theoretical values for the radii of these redox species The generalized Born approach, which does not treat the solvated species as single spheres, provided means for addressing this discrepancy and yielded effective radii that were relatively close to the measured values