Approaches to trinuclear half-sandwich carbene complexes containing 1,2-dicarba-closo-dodecaboranes

The synthesis of trinuclear half-sandwich iridium and rhodium complexes containing both N-heterocyclic carbene (NHC) and 1,2-dicarba-closo-dodecaborane ligands is described. Complexes {Cp* M[E(2)C(2)(B(10)H(10))]}(3)(L) (Cp* = pentamethylcyclopentadienyl; L = tris(2-(3-methylimidazol-2- ylidene)ethyl) amine; M = Ir (7), Rh (8); E = S (a), Se (b)) were obtained from the reactions of Cp*M[E(2)C(2)(B(10)H(10))] (M = Ir (3), Rh (4)) with a silver-NHC precursor or from the reactions of [Cp*MCl(2)](3)(L) (M = Ir (5), Rh (6)) with Li(2)E(2)C(2)(B(10)H(10)) (E = S, Se). The complexes were characterized by IR, NMR spectroscopy, elemental analysis. In addition, X-ray structure analyses were performed on complexes 7a and 8b.