Water Attack Umpolung Aromatic Systems To Release Hydrogen

The synthesis and structures of a series of cyclometalated iridium(III) complexes based on benzoxazole derivatives and triphenylphospine are reported. These complexes have a general formula (C∧N)2Ir(Cl)(pph3) [where C∧N is a monoanionic cyclometalating ligand, dfpbo = (difluorophenyl)benzoxazolato, pbo = 2-phenylbenzoxazolato, nbo = 2-(2-naphthyl)benzoxazolato, and pph3 is a triphenylphospine ligand]. The complexes (dfpbo)2Ir(Cl)(pph3) (2a), (pbo)2Ir(Cl)(pph3) (2b), and (nbo)2Ir (Cl)(pph3) (2c) have been structurally characterized by X-ray crystallography. Complex 2a shows facile umpolung in the phenyl rings of the arylphosphine ligand and displays a catalytic propensity for water splitting.