Hollow Polyhedral Structures in Small Gold-Sulfide Clusters

Using an Mid methods, we investigate the structural evolution of a family of gold-sulfide cluster anions (AumSn-). We show that this family of clusters exhibits simple size-evolution rules and novel hollow polyhedron structures. The highly stable AumSn- species such as Au6S4-, Au9S5- Au9S6-, Au10S6-, Au11S6-, Au12S8-, and Au13S8- detected in the recent ion mobility mass spectrometry experiment of Au-25(SCH2CH2Ph)(18) (Angel et al. AG Nano 2010, 4, 4691) are found to possess either quasi-tetrahedron, pyramidal, quasi-triangular prism, or quasi-cuboctahedron structures. The formation of these polyhedron structures are attributed to the high stability of the S-Au-S structural unit. A unique edge-to-face growth mechanism is proposed to understand the structural evolution of the small AumSn- cluster. A 3:2 ratio rule of Au/S is suggested for the formation of a hollow polyhedron structure among small-sized AumSn clusters.