Synthesis, Structure, and Catalytic Activity of Cyclometalated Iridium Complexes with a Bidentate POC Ligand

Abstract Synthesis, characterization and catalytic activity of cyclometalated iridium complexes with a bidentate POC ligand is presented. Metalation of POC‐H (di‐ tert ‐butyl(phenoxy)phosphane) with Ir(COD)Cl 2 proceeded rapidly at room temperature and afforded mixture of (POC)(POC‐H)IrHCl ( 1 a ) and (POC)(COD)IrHCl ( 1 b ), from which complexes (POC)(L)IrHCl where L=PPh 3 ( 1 c ), bipyridine ( 1 d ) and 2,2′‐bipyridine‐6,6′‐diol ( 1 e ) were prepared through ligand exchange. The compounds were tested in acceptorless dehydrogenation of 1‐phenylethanol and transfer dehydrogenation of ethanol in a context of comparison with pincer counterparts (POCOP)IrHCl and (PCN)IrHCl. An attempt to prepare a dihydride complex from 1 e led to dimeric complex (POC)(bipy‐diol−)IrH 2 ( 3 ) that could explain the low activity of 1 e . DFT studies provided insight into POC‐H vs POCOP‐H metalation mechanism.