Synthesis of Cp* iridium and rhodium complexes containing bidentate sp²-N-donor ligands and counter-anions [Cp*MCl ₃]^-

Complexes of the type [Cp*MCl(N-N)][X] (M = Rh and Ir) have been synthesised, where N-N is a series of bidentate ligands with sp² N-donors: bis(pyrazol-1-yl)methane (bpm), bis(1-methylimidazol-2-yl)methane (bim), bis(3,5-dimethylpyrazol-1-yl)methane (dmbpm), bis(1-methylimidazol-2-yl) ketone (bik), bis(2,4,6-trimethylphenylimino)acenapthene (mesBIAN), 2,4,6-trimethylphenylimino-(1-methyl-2-imidazolyl)methane (mesim-mim), and X = Cl^-, BF₄ ^- and the unusual anion [Cp*MCl₃]^-. All of these complexes were synthesised by treatment of [Cp*MCl₂]₂ with 2 equivalents of ligand and were isolated as air stable solids. The solid-state structures of [Cp*MCl(bpm)][Cp*MCl₃] (M = Rh and Ir) and [Cp*IrCl(bim)][Cp*IrCl₃] have been determined by single-crystal X-ray diffraction analysis. All of the structures of the bimetallic species displayed a "piano stool" configuration about the both the anionic and cationic metal centre. The solid-state structures of the monometallic iridium species [Cp*IrCl(N-N)][BF₄], where N-N = him, mesBIAN, and mesim-mim, were also determined using single-crystal X-ray diffraction analysis.