Dinuclear Di(N‐heterocyclic carb­ene) Iridium(III) Complexes as Catalysts in Transfer Hydrogenation

Abstract

AbstractTwo novel di(N‐heterocyclic carbene) complexes of formula (μ‐PyrIm‐CH2‐ImPyr)[IrCp*Cl]2(PF6)2 (1) and μ‐MeIm‐CH2(p‐C6H2)CH2‐ImMe[IrCp*Cl]2 (2) (Im = imidazol‐2‐ylidene) have been synthesised by transmetallation of the dicarbene ligand from the corresponding dicarbene silver complex, using [IrCp*(μ‐Cl)Cl]2 as an iridium precursor. The structure of complex 2 has been determined by X‐ray diffraction and is characterized by a double ortho‐metallation of the p‐xylylene bridge between the carbene units. Both complexes show good activity in the transfer hydrogenation of ketones to alcohols in 2‐propanol.