Nakajima Takayuki, Nakamae Kanako, Hatano Rika, Imai Kaho, Harada Masafumi, Ura Yasuyuki, Tanase Tomoaki
Department of Chemistry, Faculty of Science, Nara Women's University, Kitauoya-nishi-machi, Nara 630-8506, Japan.
Department of Health Science and Clothing Environment, Faculty of Human Life and Environment, Nara Women's University, Kitauoya-nishi-machi, Nara 630-8506, Japan.
Dalton Trans. 2019 Aug 28;48(32):12050-12059. doi: 10.1039/c9dt02467k. Epub 2019 Jul 26.
Multinuclear copper hydride complexes were synthesized by using a triphosphine, bis(diphenylphosphinomethyl)phenylphosphine (dpmp). The reaction of [Cu(MeCN)]PF with dpmp in 2 : 1 ratio in the presence of MeNBH or NaBH yielded a hexanuclear complex, [Cu(μ-H)(μ-dpmp)]PF (1), together with a minor product Cu(μ-H)(μ-H)(μ-dpmp) (2) in a very low yield. Complex 1 was also prepared from [CuH(PPh)], [Cu(MeCN)]PF, and dpmp in 87%, but the yield of 2 could not be improved presumably due to its instability in solution. A tetranuclear complex, [Cu(μ-H)(μ-H)(μ-dpmp)]PF (4), was obtained from the reaction of [Cu(MeCN)]PF with dpmp in 4 : 3 ratio, or that of Cu(μ-dpmp)(MeCN) (3) and dpmp, in the presence of MeNBH for both cases. The structures of 1, 2, and 4 were determined by X-ray crystallography, and the positions of hydride ligands were elucidated by DFT optimization. Complex 1 consists of a distorted trigonal anti-prismatic Cu core bridged by three L-shaped dpmp ligands and five μ-hydrides, and 2 is composed of three edge-shared tetrahedral Cu units supported by four L-shaped dpmp ligands and two μ-hydrides in the two outer Cu units and four μ-hydride ligands in the central Cu units. The structures of two outer Cu units in 2 resemble those of 4, where a Cu tetrahedron is supported by two L-shaped dpmp ligands and one dpmp-κP,P' bridge, in addition to one μ- and two μ-hydrides. Natural bond orbital analyses suggest that the hydrides act as glue between the multinuclear copper centres through electron-deficient delocalized bonding interactions, which result in partial electron migration from hydrides to Cu centres.
通过使用三膦双（二苯基膦甲基）苯基膦（dpmp）合成了多核氢化铜配合物。在甲硼烷胺（MeNBH）或硼氢化钠（NaBH）存在下，[Cu(MeCN)]PF与dpmp以2∶1的比例反应，生成了六核配合物[Cu(μ-H)(μ-dpmp)]PF（1），同时还生成了少量产物Cu(μ-H)(μ-H)(μ-dpmp)（2），产率极低。配合物1也由[CuH(PPh)]、[Cu(MeCN)]PF和dpmp以三组分反应制备，产率为87%，但2的产率可能由于其在溶液中的不稳定性而无法提高。四核配合物[Cu(μ-H)(μ-H)(μ-dpmp)]PF（4）通过[Cu(MeCN)]PF与dpmp以4∶3的比例反应，或Cu(μ-dpmp)(MeCN)（3）与dpmp在两种情况下均在甲硼烷胺存在下反应得到。通过X射线晶体学确定了1、2和4的结构，并通过密度泛函理论（DFT）优化阐明了氢化物配体的位置。配合物1由一个扭曲的三角反棱柱形铜核组成，该铜核由三个L形dpmp配体和五个μ-氢化物桥联，2由三个边共享的四面体铜单元组成，四个L形dpmp配体支撑着这三个单元，两个外部铜单元中有两个μ-氢化物，中间铜单元中有四个μ-氢化物配体。2中两个外部铜单元的结构类似于4，其中一个铜四面体由两个L形dpmp配体和一个dpmp-κP,P'桥支撑，此外还有一个μ-氢化物和两个μ-氢化物。自然键轨道分析表明，氢化物通过缺电子离域键相互作用充当多核铜中心之间的胶水，这导致电子从氢化物部分迁移到铜中心。
