Synthesis of Boron-Fused 1,4-Dithiin via Cobalt-Mediated Disulfuration of Alkyne at the o‑Carborane-9,12-dithiolate Unit

We present the first synthesis and characterization of a series of boron-fused 1,4-dithiin compounds through the reactions of newly established boron-substituted 16e half-sandwich complex Cp*Co­(9,12-S2C2B10H10) with alkynes. The generated C2S2B2 ring in these 1,4-dithiin species is a stable structural motif with electron-negative sulfur atoms, as evidenced by theoretical calculation and its solid-state self-assembly. Single-crystal X-ray analysis indicates that Ccarb–H···S hydrogen bonding is involved in the self-assemblies of these compounds, which serves as a compatible interaction with stronger Ccarb–H···π, Ccarb–H···O, or Ccarb–H···F hydrogen bonding. All new compounds are characterized by NMR, mass spectroscopy, and X-ray structural analysis.