Electrochemical Investigation of Redox Processes of Labile Cu(II)/Cu(I)-Cl Complexes by Scanning Electrochemical Microscopy
Electrochemical Investigation of Redox Processes of Labile Cu(II)/Cu(I)-Cl Complexes by Scanning Electrochemical Microscopy
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通过扫描电化学显微镜对不稳定 Cu(II)/Cu(I)-Cl 配合物的氧化还原过程进行电化学研究
DOI：
10.1021/acs.analchem.0c00797
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发表时间：
2020-08-04
影响因子：
7.4
通讯作者：
Liang, Kunjie
中科院分区：
文献类型：
--
作者：
Meng, Yao;Chen, Jiahao;Liang, Kunjie
本文报道的研究提供了通过扫描电化学显微镜（SECM）确定的Cu(II)/Cu(I)在过量氯化物体系中氧化还原反应的动力学和反应机理的详细信息。在正反馈模式下，得到的尖端伏安由两个部分重叠的还原波组成，而不是一直认为的一个准可逆过程。由于[(CuCl42)- cl - ii (H2O)]（-）与(CuCl42-)- cl - ii的配体取代反应较慢，在SECM测量的时间尺度内，(CuCl42-)- cl - ii和[(cucll3)- cl - ii (H2O)]（-）的还原种可以共存。（CuCl42-）- cl - ii的分步EC反应具有与外球反应物相同的电子转移动力学，而[(cucl13)- cl - ii (H2O)]（-）的反应遵循一致的EC路径，并且可以获得更低的速率常数，这主要是由于电子转移的非绝热特性(k(Pt)(0)/k（Au)(0) = 1.625）。本研究结果可为分析水溶液中不稳定金属配合物的电极动力学提供有价值的见解。
The studies reported here provide detailed information on the kinetics and reaction mechanism determined by the scanning electrochemical microscopy (SECM) for Cu(II)/Cu(I) redox reactions in a system with excess chloride. In positive feedback mode, the tip voltammograms obtained consist of two partially overlapping reduction waves, not one quasi-reversible process as was always thought. The reduced species of (CuCl42-)-Cl-II and [(CuCl3)-Cl-II(H2O)](-) could coexist during the time scale of SECM measurements, due to the slowness of the ligand substitution reaction of [(CuCl3)-Cl-II(H2O)](-) to (CuCl42-)-Cl-II. The stepwise EC reactions of (CuCl42-)-Cl-II have experienced the same electron transfer kinetics as do outer-sphere reactants, while the reactions of [(CuCl3)-Cl-II(H2O)](-) followed concerted EC pathways and much lower rate constants can be obtained, mainly due to the nonadiabatic character of electron transfer (k(Pt)(0)/k(Au)(0) = 1.625). The findings of this study can offer valuable insights for analyzing the electrode kinetics of labile complexes of metals in aqueous solutions.