Novel group 9 metal complexes containing an S,S′-chelating o-carboranyl ligand system: Synthesis, crystal structures, and electrochemical properties of dinuclear [{(cod)M}₂(S,S′-S₂C ₂B₁₀H₁₀)] (cod = 1,5-cyclooctadiene; M = Rh or Ir) and mononuclear Cp*CoI[S,S′-S(S=PMe₂)C ₂B₁₀H₁₀]

The synthesis of novel group 9 metal complexes containing the S,S′-chelate ligands, Li₂S₂C₂B ₁₀H₁₀ (2a) and LiS(S=PMe₂)C₂B ₁₀H₁₀ (2b), is described. Two new dinuclear complexes of the type [{(cod)M}₂(S,S′-S₂C₂B ₁₀H₁₀)] (cod = 1,5-cyclooctadiene; M = Rh (3a), or Ir (3b)) were synthesized by the reaction of chloride-bridged dimers [M(μ-Cl)(cod)]₂ with one molar equivalent of the corresponding dilithium dithiolato ligand Li₂S₂C₂B ₁₀H₁₀ (2a). X-ray crystal structure analysis of 3a revealed a dinuclear structure in which each (cod)Rh unit is attached to a distinct sulfur atom of a 1,2-dithio-o-carboranyl ligand (2a). Additionally, the electrochemical properties of 3a and 3b were investigated by cyclic voltammetry. In an analogous manner, reaction of the lithium dithiolato ligand LiS(S=PMe₂)C₂B₁₀H₁₀ (2b) with Cp*CoI₂(CO) produced a mononuclear dithiolato complex, [Cp*CoI{(S,S′-S(S=PMe₂)C₂B₁₀H ₁₀)}] (4), which was characterized by single-crystal X-ray analysis.