Tang Hui Min, Fan Wai Yip
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
Inorg Chem. 2021 Dec 6;60(23):17933-17941. doi: 10.1021/acs.inorgchem.1c02524. Epub 2021 Nov 5.
A series of Schiff-base nickel(II) complexes were prepared from the reaction of nickel(II) acetate with -salicylcysteamine [HO-CH-CH═N(CH)SH] ligands. These complexes were analyzed to be dimeric nickel complexes containing two bridging thiolato ligands. Using cyclic voltammetry, they were found to be efficient homogeneous proton reduction electrocatalysts when acetic acid was used as the proton source in acetonitrile. Catalysis was triggered upon electrochemical reduction of the nickel complex. In particular, rate constants () in the range of 10 s at moderate overpotentials of 0.5-0.6 V were achieved when chloro- or bromo-containing nickel complexes were used. Combined with the experimental data, density functional theory calculations lent support to an ECEC mechanism, with the first electrochemical reduction step contributing significantly to the rate-determining step.
通过乙酸镍与 - 水杨基半胱胺[HO-CH-CH═N(CH)SH]配体反应制备了一系列席夫碱镍(II)配合物。经分析，这些配合物为含有两个桥连硫醇盐配体的二聚镍配合物。使用循环伏安法，发现当在乙腈中使用乙酸作为质子源时，它们是高效的均相质子还原电催化剂。镍配合物的电化学还原引发催化作用。特别是，当使用含氯或含溴的镍配合物时，在0.5 - 0.6 V的适度过电位下，速率常数(k)达到10 s的范围。结合实验数据，密度泛函理论计算支持ECEC机理，其中第一个电化学还原步骤对速率决定步骤有显著贡献。
