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Investigation on the photophysical properties of a series of promising phosphorescent iridium (III) complexes with modified cyclometalating ligands
摘要： Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were applied to investigate the electronic structures and photophysical properties of a series of phosphorescent iridium (III) complexes, [(C^N)2Ir(N^N)]+(PF6)(cid:2), in which C^N = 4-aryl-1-benzyl-1H-1, 2, 3-triazoles. Herein, aryl = phenyl, biphenyl, three-phenyl aromatic for complexes 1a, 2a, 3a (N^N = 2, 20-bipyridine) and aryl = 40, 60-di?uorophenyl, 60-?uoro-biphenyl, 60-?uoro-three-phenyl aromatic for complexes 1b, 2b, 3b (N^N = 4, 40-di-tert-butyl-2, 20-bipyridine), respectively. The geometric/electronic con?gurations, absorption/emission properties and phosphorescent performances have been outlined for each of the complexes. Based on the two simpli?cations presented in this paper and the available experimental data, the phosphorescent radiative rates for complexes 1a-3b were approximately obtained to be: 1.20 (cid:3) 106 s(cid:2)1, 1.68 (cid:3) 105 s(cid:2)1, 2.19 (cid:3) 107 s(cid:2)1, 3.85 (cid:3) 106 s(cid:2)1, 1.85 (cid:3) 107 s(cid:2)1 and 1.50 (cid:3) 107 s(cid:2)1, respectively. In view of the electroluminescent applications in OLED, our present research work is of great importance for the design and synthesis of organo-transition metal complexes with improved phosphorescent performances.
关键词： Phosphorescence,Photophysical properties,Time-dependent DFT,Iridium (III) complexes,Density functional theory (DFT)
更新于2025-09-19 17:15:36
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Distortion‐Controlled Red‐Shift of Organic Dye Molecules
摘要： We show quantum chemically how structural distortion of an aromatic dye molecule can be leveraged to rationally tune its optoelectronic properties. Using a quantitative Kohn-Sham MO approach in combination with Time-Dependent DFT (TD-DFT), we have investigated the influence of various structural and electronic tuning parameters on the HOMO–LUMO gap of a benzenoid model dye, amongst others: (i) out-of-plane bending of the aromatic core; (ii) bending of the bridge with respect to the core; (iii) the nature of the bridge itself; and (iv) π-π stacking. Our study reveals the coupling of multiple structural distortions as a function of bridge length and number of bridges in benzene to be chiefly responsible for a decreased HOMO–LUMO gap and consequently the red-shifting of the absorption wavelength associated with the lowest singlet excitation (ca. 560 nm) in our model cyclophane systems. These physical insights together with a rational approach for tuning the oscillator strength were leveraged for the proof-of-concept design of the intense near-infrared (NIR) absorbing cyclophane dye 18 at 785 nm. Our design may contribute to a new class of distortion-controlled NIR absorbing organic dye molecules.
关键词： Cyclophane,NIR Absorption,Structural Distortion,HOMO–LUMO gap,Time-Dependent DFT
更新于2025-09-11 14:15:04