Au3(μ3-S)(0e) elementary block: new insights into ligated gold clusters with μ3-sulfido motifs.

An understanding of the structural stability and formation mechanism of ligated gold nanoclusters with triply coordinated μ3-sulfido (μ3-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 Au3(μ3-S) with zero valence electrons [referred to as Au3(μ3-S)(0e)] has been identified, which describes all crystallized ligated gold clusters with μ3-S motifs, in conjunction with the previously reported Au3(2e) and Au4(2e) elementary blocks, in a grand unified model (GUM). This Au3(μ3-S)(0e) elementary block has a tripod structure with the S atom bonding to three Au atoms in a μ3 bridging mode, and can be considered as a μ3-S atom balancing out the 2e valence electrons of the Au3(2e) block. Using Au3(μ3-S) as a building block, a special group of quasi-fullerene hollow-cage [Au3n(μ3-S)2n]n- gold(i) μ3-S clusters are designed, which exhibit high stabilities. In addition, a series of theoretical structures are predicted to be increasingly stable after introducing μ3-S atoms, based on the crystallized clusters. Overall, the introduction of a Au3(μ3-S)(0e) elementary block can help with the understanding of diverse structures of ligated gold clusters with μ3-S motifs, thereby assisting the rational design of new forms of gold nanoclusters.