Synthesis and Characterization of Binuclear Half-Sandwich Iridium and Rhodium Carbene Complexes Containing 1,2-Dichalcogenolato Carborane or Carbonato Ligands

Reactions of bi-NHC ligands with the 16-electron half-sandwich Ir and Rh dichalcogenolato carborane complexes Cp*M[E2C2(B10H10)] (M = Ir, Rh; E = S, Se) or 16-electron half-sandwich Ir and Rh carbonate complexes Cp*M(μ-O)2CO (M = Ir, Rh) give corresponding 18-electron binuclear complexes of the type [{Cp*M(E2C2(B10H10))}2L] (L = 1,1′-(1,2-ethanediyl)bis(3-methylimidazolin-2-ylidene); M = Ir, E = S (4a), Se (4b); M = Rh, E = S (5a), Se (5b)) and [Cp*M(μ-O)2CO]2L (M = Ir (8), Rh (9)). Complexes 4−9 can also be obtained directly from the reactions of [Cp*MCl2]2L (M = Ir (2), Rh (3)) with Li2[E2C2(B10H10)] or Na2CO3 in high yields. The complexes were characterized by IR, NMR spectroscopy, and elemental analysis. In addition, the molecular structures of 4b, 5a, and 8 have been determined by X-ray crystallography.