Department of Chemistry, National Dong Hwa University, Hualien, Taiwan 97401, R. O. C.
Inorg Chem. 2011 Sep 5;50(17):8410-7. doi: 10.1021/ic2009896. Epub 2011 Aug 1.
The hydrido copper(I) and silver(I) clusters incorporating 1,1-dicyanoethylene-2,2-dithiolate (i-MNT) ligands are presented in this paper. Reactions of M(I) (M = Cu, Ag) salts, Bu(4)N[S(2)CC(CN)(2)], with the anion sources ([Bu(4)N][BH(4)] for H(-), [Bu(4)N][BD(4)] for D(-)) in an 8:6:1 molar ratio in THF produce octanuclear penta-anionic Cu(I)/Ag(I) clusters, Bu(4)N[M(8)(X){S(2)CC(CN)(2)}(6)] (M = Cu, X = H, 1(H); X = D, 1(D); M = Ag, X = H, 2(H); X = D, 2(D)). They can also be produced from the stoichiometric reaction of M(8)(i-MNT)(6)(4-) with the ammonium borohydride. All four compounds have been fully characterized spectroscopically ((1)H and (13)C NMR, IR, UV-vis) and by elemental analyses. The deuteride-encapsulated Cu(8)/Ag(8) clusters of 1(D) and 2(D) are also characterized by (2)H NMR. X-ray crystal structures of 1(H) and 2(H) reveal a hydride-centered tetracapped tetrahedral Cu(8)/Ag(8) core, which is inscribed within an S(12) icosahedron formed by six i-MNT ligands, each in a tetrametallic-tetraconnective (μ(2), μ(2)) bonding mode. The encapsulated hydride in 2(H) is unequivocally characterized by both (1)H and (109)Ag NMR spectroscopies, and the results strongly suggest that the hydride is coupled to eight magnetically equivalent silver nuclei on the NMR time scale. Therefore, a fast interchange between the vertex and capping silver atoms in solution gives a plausible explanation for the perceived structural differences between the Ag(8) geometry deduced from the X-ray structure and the NMR spectra.
本文介绍了含有 1,1-二氰基乙烯-2,2-二硫代羧酸根（i-MNT）配体的氢化物铜（I）和银（I）簇合物。反应中，M（I）（M = Cu，Ag）盐、[Bu（4）N]（2）[S（2）CC（CN）（2）]与阴离子源[Bu（4）N][BH（4）]（用于 H（-），[Bu（4）N][BD（4）]（用于 D（-））以 8:6:1 的摩尔比在 THF 中反应生成八核五阴离子铜（I）/银（I）簇合物[Bu（4）N]（5）[M（8）（X）{S（2）CC（CN）（2）}（6）]（M = Cu，X = H，1（H）；X = D，1（D）；M = Ag，X = H，2（H）；X = D，2（D））。它们也可以由化学计量比的 M（8）（i-MNT）（6）（4-）与铵硼氢化反应制得。所有四个化合物都通过光谱学（1H 和 13C NMR、IR、UV-vis）和元素分析进行了全面表征。氘化物包封的 Cu（8）/Ag（8）簇合物 1（D）和 2（D）也通过 2H NMR 进行了表征。1（H）和 2（H）的 X 射线晶体结构揭示了一个以氢化物为中心的四面封端四面体 Cu（8）/Ag（8）核，该核被六个 i-MNT 配体形成的 S（12）二十面体包围，每个配体都处于四金属四连接（μ（2），μ（2））键合模式。2（H）中包封的氢化物通过 1H 和 109Ag NMR 光谱学得到了明确的表征，结果强烈表明，在 NMR 时间尺度上，氢化物与八个磁等价的银核耦合。因此，在溶液中顶点和封端银原子之间的快速交换为从 X 射线结构和 NMR 光谱推导出的 Ag（8）几何结构之间的感知差异提供了一个合理的解释。
