Synthesis, structure, and catalytic activity of a new chiral NHC–iridium(III) complex

The new chiral NHC–iridium complex 3 has been prepared in CH3CN from the reaction between [Ir(COD)Cl]2, NaOAc, KI, and dibenzimidazolium salt 2 which is derived from (S)-2,2′-diamino-6,6′-dimethyl-1,1′-biphenyl. Complex 3 has been characterized by various spectroscopic techniques, elemental analyses, and X-ray diffraction analysis. It has a distorted-octahedral IrC2N2IH core structure, and shows good catalytic activity for the asymmetric hydrosilylation of arylmethyl ketones, leading to 1-arylethanol with moderate ee values.