Structural evolution and electronic properties of boron sulfides (B2S3)n (n = 1–6): insights from DFT calculations†

The low-energy isomers of boron sulfides (B₂S₃)_n (n = 1–6) were constructed by using B₂S₃ as the building block, and their structure, stability, and reactivity toward small molecules have been explored by density functional theory (DFT) calculations. It is found that the low-energy isomers of (B₂S₃)_n clusters are of rich bonding characteristics for their structural constituents, such as [S−B−S], [B₂S₃], [B₃S₃], [S], etc. The planar or non-planar B₂S₂ rings, as the basic structural units, are bridged together by the S atoms to form the most stable structures of (B₂S₃)_n clusters with n ≥ 2. These low-energy (B₂S₃)_n clusters are predicted to be stable both structurally and electronically, and their boron centers show relatively high activity to the binding of small molecules NH₃ and CO, until all boron atoms are ligated by NH₃ or CO. The present results provide new insights into the structure and properties of (B₂S₃)_n clusters, which are beneficial to the development of boron chemistry and the application of boron-based materials.