Four new cyclometalated phenylisoquinoline-based Ir(III) complexes: Syntheses, structures, properties and DFT calculations

Four new cyclometalated phenylisoquinoline-based iridium(III) complexes [Ir(C∧N)2(bipy)]PF6 (5a–5d) (bipy = 2,2′-bipyridine) have been synthesized and fully characterized, where the C∧N ligands are 1-(4-(trifluoromethyl)phenyl)isoquinoline, 4-(isoquinolin-1-yl)benzaldehyde, 4-(isoquinolin-1-yl)benzonitrile and 1-(3-fluoro-4-methylphenyl)isoquinoline, respectively. The crystal structures of 5a and 5c have been determined. The photophysical and electrochemical properties of these new complexes 5a–5d have been studied. All Ir(III) complexes exhibit orange phosphorescence in dichloromethane solution at room temperature with a maximum at 593–618 nm, quantum yield of 0.046–0.16. The frontier molecular orbital diagrams and the lowest-energy electronic transitions of 5a–5d have been calculated with density functional theory (DFT) and time-dependent DFT (TD-DFT).