Zeng Chenjie, Chen Yuxiang, Liu Chong, Nobusada Katsuyuki, Rosi Nathaniel L, Jin Rongchao
Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
Sci Adv. 2015 Oct 9;1(9):e1500425. doi: 10.1126/sciadv.1500425. eCollection 2015 Oct.
Magic-sized clusters, as the intermediate state between molecules and nanoparticles, exhibit critical transitions of structures and material properties. We report two unique structures of gold clusters solved by x-ray crystallography, including Au40 and Au52 protected by thiolates. The Au40 and Au52 clusters exhibit a high level of complexity, with the gold atoms in the cluster first segregated into four-atom tetrahedral units-which then coil up into a Kekulé-like ring in the Au40 cluster and a DNA-like double helix in Au52. The solved structures imply a new "supermolecule" origin for revealing the stability of certain magic-sized gold clusters. The formation of supermolecular structures originates in the surface ligand bonding-induced stress and its propagation through the face-centered cubic (FCC) lattice. Moreover, the two structures reveal anisotropic growth of the FCC lattice in the cluster regime, which provides implications for the important roles of ligands at the atomic level. The rich structural information encoded in the Au40 and Au52 clusters provides atomic-scale insight into some important issues in cluster, nanoscale, and surface sciences.
幻数尺寸的团簇作为分子与纳米粒子之间的中间状态，呈现出结构和材料性质的临界转变。我们报道了通过X射线晶体学解析出的金团簇的两种独特结构，包括由硫醇盐保护的Au40和Au52。Au40和Au52团簇展现出高度的复杂性，团簇中的金原子首先分离成四原子四面体单元，然后在Au40团簇中盘绕成类似凯库勒式的环，在Au52团簇中盘绕成类似DNA的双螺旋。解析出的结构暗示了揭示某些幻数尺寸金团簇稳定性的新“超分子”起源。超分子结构的形成源于表面配体键合诱导的应力及其通过面心立方（FCC）晶格的传播。此外，这两种结构揭示了团簇体系中FCC晶格的各向异性生长，这为配体在原子水平上的重要作用提供了启示。Au40和Au52团簇中编码的丰富结构信息为团簇、纳米尺度和表面科学中的一些重要问题提供了原子尺度的见解。
