Huang Lei, Yan Juanzhu, Ren Liting, Teo Boon K, Zheng Nanfeng
Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory for Physical Chemistry of Solid Surfaces, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Dalton Trans. 2017 Feb 14;46(6):1757-1760. doi: 10.1039/c6dt04419k.
We report herein the synthesis and structure of a 45-atom trigonal-prismatic Au-Ag bimetallic nanocluster, formulated as AuAg(SPhCl)(PPh), based on single-crystal X-ray crystallographic determination. The structure can be described as a core-shell structure with a tricapped trigonal prismatic (ttp1) Au core encaged in a larger (frequency-two) tricapped trigonal prismatic (ttp2) Ag shell. The cluster is terminated by six Ag(PPh) moieties which, along with ttp2 and 27 thiolates, constitute the outer trigonal-prismatic (TP) shell. Each of the three nearly coplanar yet severely distorted "square" faces of TP contains 13 Ag atoms which are arranged in a way reminiscent of the (100) face of a face-centered cubic (fcc) structure. Of the 30 edges formed by these quasi-(100) faces of the TP, only 27 are bridged by the thiolate ligands; three are vacant, one on each "square" face. It is believed that these peculiar vacant ligand sites are caused by steric hindrance of the thiolate ligands in combination with the superatomic electronic shell closing of 1S1P1D rendering 9(ttp1) + 30(ttp2) + 6(TP) - 27(SR) = 18 jellium electrons.
在此，我们基于单晶X射线晶体学测定，报告了一种45原子三角棱柱形金 - 银双金属纳米团簇的合成与结构，其化学式为AuAg(SPhCl)(PPh)。该结构可描述为一种核壳结构，其中一个三帽三角棱柱形（ttp1）金核被包裹在一个更大的（频率为二）三帽三角棱柱形（ttp2）银壳中。该团簇由六个Ag(PPh)部分终止，这些部分与ttp2和27个硫醇盐一起构成外部三角棱柱形（TP）壳。TP的三个近乎共面但严重扭曲的“方形”面中的每一个都包含13个银原子，其排列方式让人联想到面心立方（fcc）结构的（100）面。在由TP的这些准（100）面形成的30条边中，只有27条由硫醇盐配体桥接；三条边是空的，每个“方形”面上有一条。据信，这些特殊的空配体位点是由硫醇盐配体的空间位阻与1S1P1D的超原子电子壳层闭合相结合导致的，使得9(ttp1) + 30(ttp2) + 6(TP) - 27(SR) = 18个电子气电子。
