Inoue Satoshi, Mitsuhashi Manabu, Ono Takeshi, Yan Yin-Nan, Kataoka Yusuke, Handa Makoto, Kawamoto Tatsuya
Department of Chemistry, Faculty of Science, Kanagawa University , 2946 Tsuchiya, Hiratsuka 259-1293, Japan.
Department of Material Science, Interdisciplinary Graduate School of Science and Engineering, Shimane University , 1060 Nishikawatsu, Matsue 690-8504, Japan.
Inorg Chem. 2017 Oct 16;56(20):12129-12138. doi: 10.1021/acs.inorgchem.7b01244. Epub 2017 Sep 22.
Three Schiff-base-type nickel(II) complexes (1a-3a) and the corresponding noninnocent-type complexes (1b-3b) were synthesized, and the equilibria between these valence isomers were observed in tetrahydrofuran (THF) at room temperature. The electronic state of the noninnocent-type nickel complex was also confirmed by isolation of the one-electron-reduced species. The catalytic ability for the photogeneration of hydrogen from water was examined about 1a-3a and 1b-3b in the presence of a photosensitizer and a sacrificial electron donor. Then, a Schiff-base-type complex with chlorine atoms (2a) and a noninnocent-type complex with methyl groups (3b) on the pendant phenyl rings being present as the minor species in THF exhibited high activity of over 400 turnover numbers. The dynamic light scattering and transmission electron microscopy measurements suggested the formation of NiS-like aggregate species under photocatalytic conditions. The electrocatalytic activities of the nickel complexes for hydrogen production were also investigated, and a plausible reaction mechanism was proposed on the basis of a combined electrochemical and density functional theory study.
合成了三种席夫碱型镍（II）配合物（1a - 3a）以及相应的非单纯型配合物（1b - 3b），并在室温下于四氢呋喃（THF）中观察到了这些价异构体之间的平衡。通过分离单电子还原产物也证实了非单纯型镍配合物的电子态。在存在光敏剂和牺牲电子供体的情况下，考察了1a - 3a和1b - 3b从水中光催化产氢的能力。然后，在THF中作为次要物种存在的、在侧链苯环上带有氯原子的席夫碱型配合物（2a）和带有甲基的非单纯型配合物（3b）表现出超过400个周转数的高活性。动态光散射和透射电子显微镜测量表明在光催化条件下形成了类NiS聚集体物种。还研究了镍配合物的电催化产氢活性，并基于电化学和密度泛函理论的联合研究提出了合理的反应机理。
