Orange-Red Phosphorescent Iridium(III) Complexes Bearing Bisphosphine Ligands: Synthesis, Photophysical and Electrochemical Properties, and DFT Calculations

Abstract

Nine new phosphorus-coordinated iridium(III) complexes of the form [Ir(C∧N)2(P∧P)]PF6, [Ir(F-piq)2(xantphos)]PF6 (1), [Ir(F-piq)2(binap)]PF6 (2), [Ir(F-piq)2(dppp)]PF6 (3), [Ir(Me-piq)2(xantphos)]PF6 (4), [Ir(Me-piq)2(binap)]PF6 (5), [Ir(Me-piq)2(dppp)]PF6 (6), [Ir(CF3O-piq)2(xantphos)]PF6 (7), [Ir(CF3O-piq)2(binap)]PF6 (8), and [Ir(CF3O-piq)2(dppp)]PF6 (9) (F-piq = 1-(4-fluorophenyl)isoquinoline, Me-piq = 1-(p-tolyl)isoquinoline, CF3O-piq = 1-(4-(trifluoromethoxy)phenyl)isoquinoline, xantphos = 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene, binap = 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, dppp = 1,3-bis(diphenylphosphanyl)propane), have been synthesized and fully characterized. The crystal structures of 1, 7, and 9 have been determined by X-ray analysis. The most representative molecular orbital energy-level diagrams and the lowest energy electronic transitions of 1–9 have been calculated with density functional theory (DFT) and time-dependent DFT (TD-DFT). All of the complexes are orange-red emiss...