The C-substituted charge-compensated dicarbollide [7-SMe2-7,8-C2B9H10]−: Synthesis and room-temperature rearrangement of the iridium complex

The reaction of 7-SMe₂-7,8-C₂B₉H₁₀]⁻ with (cod)IrCl]₂ at room temperature affords iridacarborane 1-cod-8-SMe₂-1,2,8-IrC₂B₉H₁₀. The metal insertion is accompanied by polyhedral rearrangement of the carborane ligand with migration of the substituted carbon atom from the metal bonded pentagonal face. The electronic factors rather than steric ones play the main role in the ligand rearrangement. According to DFT calculations the final iridacarborane is more stable by 6–7 kcal mol^− 1 than the transient pseudocloso-1-cod-2-SMe₂-1,2,3-IrC₂B₉H₁₀ complex. Structures of 7-SMe₂-7,8-C₂B₉H₁₁ and 2 were determined by X-ray diffraction.