| Using 2-pyrimidinyl thiophene (pymbt, L1), 2-pyrimidinyl benzothiophene (pymbtp, L2) as the cyclometalated main ligands and tetraphenylimidodiphosphinate (Htpip) as the O^O ancillary ligand, two novel phosphorescent iridium complexes (pymbt)2Ir(tpip) (Ir1) and (pymbtp)2Ir(tpip) (Ir2) were synthesized. Their structures were characterized by 1H-NMR, MS and elemental analysis method. Their photophysical properties were studied by UV-Vis absorption and photoluminescence spectra. The results show that the maximum emission peaks of iridium(III) complexes Ir1 and Ir2 in CH2Cl2 solution are 563 nm and 619 nm, respectively, corresponding to orange and red light emission. In anhydrous and oxygen-free CH2Cl2 solution, the relative quantum efficiencies are 6.3% and 10.1%, respectively, and the corresponding phosphorescence lifetime is 0.50ms and 0.63 ms. The lowest energy electronic transitions of complexes Ir1 and Ir2 were calculated by time-dependent density functional theory (TDDFT), and the results are consistent with the corresponding trend in the experimental spectra. |
