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 emissive with quantum efficiencies of 3.2–24.4% and lifetimes of 1.77–3.19 μs in degassed CH2Cl2 solution at room temperature. These research results reveal that the Me-piq C∧N ligand and xantphos P∧P ligand are beneficial for a red shift of absorption and emission wavelength. Complex 4 has better charge transfer ability, which probably promises its use as a red-phosphorescent material.

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Heteroleptic cyclometalated iridium(III) complexes (Ir1-Ir5) featuring pizbased ligands and acetylacetone ancillary ligand are synthesized and characterized. Their photophysical and electrochemical properties were studied, and DFT calculations were used to further support the experiment results. All the complexes emit yellow color with quantum yields of 12.2-56.5% in dichloromethane solution at room temperature, and the emission originates from a hybrid 3 MLCT/ 3 ILCT/ 3 LLCT excited state.

Four new cationic iridium (III) complexes: [(cf3piq)2Ir(pzpy)]+PF6− (Ir1), [(cf3piq)2Ir(pzpyz)]+PF6− (Ir2), [(cf3piq)2Ir(impy)]+PF6− (Ir3), and [(cf3piq)2Ir(impyz)]+PF6− (Ir4) (where cf3piq=1‐(4‐(trifluoromethyl)phenyl)isoquinoline, pzpy=2‐(1H‐pyrazol‐3‐yl)pyridine, pzpyz=2‐(1H‐pyrazol‐3‐yl)pyrazine, impy=2‐(1H‐imidazol‐2‐yl)pyridine, and impyz=2‐(1H‐imidazol‐2‐yl)pyrazine) have been synthesized and fully characterized. The single crystal structure of Ir3 has been determined by X‐ray diffraction, and confirmed to have two hydrogen bonds (C14−H14⋅⋅⋅N2 and C57−H57⋅⋅⋅N9) and one intermolecular π‐π stacking interaction. The UV‐vis absorption, photoluminescence, and electrochemistry properties of all complexes have been studied. These complexes emit orange‐red photoluminescence with quantum yields of 28–46 % and excited state lifetimes of 0.48‐0.65 μs in CH2Cl2 solution at room temperature. Based on the DFT calculations, we concluded that their emission originated predominantly from a hybrid 3MLCT/3ILCT excited state.

Three new BPTA-bridged binuclear copper(I) complexes bearing three different diphosphine ligands, namely, [(Cu I ) 2 (Xantphos) 2 (BPTA)](BF 4 ) 2 (Cu1), [(Cu I ) 2 (Dppp) 2 (BPTA)](BF 4 ) 2 (Cu2), and [(Cu I ) 2 (Binap) 2 (BPTA)](BF 4 ) 2 (Cu3), have been synthesized and characterized. The X-ray structure analyses of complex Cu3 show that the central copper(I) ion adopts a distorted tetrahedral geometry. Complexes Cu1 and Cu2 exhibit greenish-yellow emission with excited-state lifetime (13μs and 27μs) and photoluminescence quantum yields (6.86 % and 0.62 %) at room temperature in the solid state. Emission decay measurement and theoretical calculation suggest that the transition nature of their emission could be assigned to 3 MLCT/ 3 LC excited states. More interesting, complexes Cu1-Cu3 are weakly emissive in solution but become strongly luminescent in solid state, so it has the aggregation induced emission (AIE) behavior.