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'-S2C2B10H10)] (cod = 1,5-cyclooctadiene;M = Rh OR Ir)] and Mononclear Cp*CoI[S,S'-S(S=PMe2)C2B10H10] Metal Complexs

The synthesis of novel group 9 metal complexes containing the S,S'-chelate ligands, Li₂S₂C₂B₁₀H₁₀ (2a) and LiS(S=PMe₂)C₂B₁₀H_10} (2b), is described. Two new dinuclear complexes of the type [(cod)M₂(S,S'-S₂C₂B₁₀H₁₀)] (cod = 1,5-cyclooctadiene; M = Rh (3a), or Ir (3b)) were synthesized by the reaction of chloridebridged dimers [M(μ-Cl)(cod)]₂ with one molar equivalent of the corresponding dilithium dithiolato ligand Li₂S₂C₂B₁₀H₁₀ (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)C₂B₁₀H₁₀)] (4), which was characterized by single-crystal X-ray analysis.