An unprecedented, figure-of-eight, dinuclear iridium(I) dicarbene and new iridium(III) 'pincer' complexes

摘要

An unusual dinuclear Ir(I) complex bridged by two N-hetero-cyclic biscarbene ligands, forming a 20-membered, figure-of-eight dimetallacycle, and new C_(NHC)CC_(NHC) pincer complexes of Ir(m) have been obtained directly from the bis(imidazolium) precursors and [Ir(μ-Cl)(cod)]_2.rnN-Heterocyclic carbene (NHC) ligands have been extensively studied during the last decade and continue to be of considerable interest, notably for their contribution to coordination and organometallic chemistry and their numerous applications in homogeneous catalysis. Their electron donor properties make them attractive alternatives to tertiary phosphine ligands. Metal complexes containing planar, rigid, tridentate ligands which incorporate at least one NHC have been intensively investigated during the last ten years and found to exhibit unique catalytic properties.