| Abstract: To study the effect of substituents on the photo-physical properties of iridium phosphorescent complexes, four identical methyl (Me), methoxy (MeO), fluorine (F), or trifluoromethyl (CF3) groups were introduced into the 2and 4-positions of the two phenyl groups onto the 2,4-bis(2,4-disubstituted phenyl) pyridine [2,4-(2,4-2R-phenyl)2py, R=Me (HL1), MeO (HL2), F (HL3), CF3 (HL4)] main ligands at the same time. Four iridium phosphorescent complexes (Ln)2Ir(acac) [n=1 (Ir1), 2 (Ir2), 3 (Ir3), 4(Ir4)] were synthesized by using HL1, HL2, HL3, or HL4 as the main ligand and acetylacetone (Hacac) as the auxiliary ligand. The composition, spatial structure, and molecular stacking of all iridium phosphorescent complexes were characterized by elemental analysis, nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR), and single-crystal X-ray diffraction. The results indicated that all four iridium phosphorescent complexes exhibit slightly distorted octahedral configurations. The central iridium(Ⅲ) coordinates with the C and N atoms of the two main ligands to form a five-membered chelating ring while coordinating with the two oxygen atoms of the acetylacetone auxiliary ligand to form a stable six-membered chelating ring. The results are consistent with the chemical structure of the target compound. A comprehensive and systematic study was conducted on the photophysical properties of iridium phosphorescent complexes through solution and solid photoluminescence spectroscopy, UV Vis absorption spectroscopy, fluorescence lifetime, and theoretical calculations. The complexes Ir1, Ir2, Ir3, and Ir4 in solution with the photoluminescence quantum yields of 68%, 83%, 88%, and 81% exhibited maximum emission peaks at 537, 515, 514, and 553 nm, fluorescence lifetime of 26.75, 163.93, 64.50, and 330.39 ns, and in solid with maximum emission peaks at 536, 520, 520, and 546 nm, respectively. Four iridium phosphorescent complexes have different electron cloud distribution characteristics, and substituents can regulate the distribution of electron clouds on the benzene ring, further achieving the control of photophysical properties and chemical structure, such as emission wavelength in solution and solid-state, emission color, fluorescence lifetime, and molecular stacking. |
| 常桥稳,张柯,黄光英,李诺楠,刘伟平,白福全,晏彩先,冯洋洋,左川.取代基团修饰苯基吡啶类铱磷光配合物的合成、结构及光物理性能[J].无机化学学报,2025,41(2):235-244. |
