Hollow polyhedral structures in small gold-sulfide clusters

Using ab initio methods, we investigate the structural evolution of a family of gold-sulfide cluster anions (Au_mS_n^-). We show that this family of clusters exhibits simple size-evolution rules and novel hollow polyhedron structures. The highly stable Au_mS _n^- species such as Au₆S₄ ^-, Au₉S₅^-, Au₉S ₆^-, Au₁₀S₆^-, Au ₁₁S₆^-, Au₁₂S₈ ^-, and Au₁₃S₈^- detected in the recent ion mobility mass spectrometry experiment of Au₂₅(SCH ₂CH₂Ph)₁₈ (Angel et al. ACS Nano2010, 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 Au_mS_n^- cluster. A 3:2 ratio rule of Au/S is suggested for the formation of a hollow polyhedron structure among small-sized Au_mS_n clusters. © 2011 American Chemical Society.