Syntheses of PBP Pincer Iridium Complexes: A Supporting Boryl Ligand

We synthesized a PBP pincer ligand precursor 2 and demonstrated its complexation with iridium(l) to afford the coordinatively unsaturated [PBP](hydrido)chloroiridium complex 3 via B-H oxidative addition. The reaction of 3 with carbon monoxide produced [PBP](hydrido)chloro(carbonyl)iridium 7. The longer Ir-Cl bond length of 7 than that of 8 revealed a stronger a-donor ability of the PBP ligand than that of PCP. Complex 3 was also converted to [PBP](ethylene)iridium(l) complex 9 by the reaction with LiTMP under an ethylene atmosphere.