Au(μ-S)(0e) elementary block: new insights into ligated gold clusters with μ-sulfido motifs.

An understanding of the structural stability and formation mechanism of ligated gold nanoclusters with triply coordinated μ-sulfido (μ-S) motifs is important not only for gold chemistry but also for the design of more effective catalysts or drug carriers for various applications. In this article, a new elementary block Au(μ-S) with zero valence electrons [referred to as Au(μ-S)(0e)] has been identified, which describes all crystallized ligated gold clusters with μ-S motifs, in conjunction with the previously reported Au(2e) and Au(2e) elementary blocks, in a grand unified model (GUM). This Au(μ-S)(0e) elementary block has a tripod structure with the S atom bonding to three Au atoms in a μ bridging mode, and can be considered as a μ-S atom balancing out the 2e valence electrons of the Au(2e) block. Using Au(μ-S) as a building block, a special group of quasi-fullerene hollow-cage [Au(μ-S)] gold(i) μ-S clusters are designed, which exhibit high stabilities. In addition, a series of theoretical structures are predicted to be increasingly stable after introducing μ-S atoms, based on the crystallized clusters. Overall, the introduction of a Au(μ-S)(0e) elementary block can help with the understanding of diverse structures of ligated gold clusters with μ-S motifs, thereby assisting the rational design of new forms of gold nanoclusters.