Comparative study of electron transfer reactions at the ionic liquid/water and organic/water interfaces.
Comparative study of electron transfer reactions at the ionic liquid/water and organic/water interfaces.
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DOI：
10.1021/ja045420t
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发表时间：
2004-11
影响因子：
15
通讯作者：
Francois Laforge;T. Kakiuchi;F. Shigematsu;M. Mirkin
中科院分区：
文献类型：
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作者：
Francois Laforge;T. Kakiuchi;F. Shigematsu;M. Mirkin
在水/离子液体（IL）界面的电子转移（ET）反应的速率已被测量的第一次使用扫描电化学显微镜。二茂铁溶解在1-辛基-3-甲基咪唑双（三氟甲基磺酰基）酰亚胺和铁氰化物水溶液（0.4 M-1 cm s-1）之间的界面ET的标准双分子速率常数被发现是在水/1，2-二氯乙烷界面处测得的相应速率常数的约30倍。在宽范围的界面电位降值（>200 mV）上研究了ET速率的驱动力依赖性。所观察到的Butler-Volmer型的依赖性进行了讨论的界面模型。还在水溶液与IL和1，2-二氯乙烷的混合物之间的界面处探测ET。系统地改变该混合物中的摩尔分数以研究从水/有机物到水/IL界面的过渡。所观察到的速率常数随着1，2-二氯乙烷的摩尔分数的增加而降低，与先前报道的电化学速率常数和溶液中氧化还原物种的扩散系数之间的直接相关性相反。
The rates of electron transfer (ET) reactions at the water/ionic liquid (IL) interface have been measured for the first time using scanning electrochemical microscopy. The standard bimolecular rate constant of the interfacial ET between ferrocene dissolved in 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and aqueous ferricyanide (0.4 M-1 cm s-1) was found to be approximately 30 times higher than the corresponding rate constant measured at the water/1,2-dichloroethane interface. The driving force dependence of the ET rate was investigated over a wide range of the interfacial potential drop values (>200 mV). The observed Butler-Volmer-type dependence is discussed in terms of the interfacial model. The ET was also probed at the interface between aqueous solution and the mixture of the IL and 1,2-dichloroethane. The mole fractions in this mixture were varied systematically to investigate the transition from the water/organic to the water/IL interface. The observed decrease in the rate constant with increasing mole fraction of 1,2-dichloroethane is in contrast with the previously reported direct correlation between the electrochemical rate constant and the diffusion coefficient of redox species in solution.