Effects of geometric isomerism and regioisomerism on photophysical properties of iridium(iii) complexes
- 1College of Information Technology, Jilin Engineering Research Center of Optoelectronic Materials and Devices, Jilin Normal University Siping Jilin 136000 China
- 2Jilin Provincial Key Laboratory of Wide Bandgap Semiconductor Material Growth and Device Applications, Jilin Normal University Changchun Jilin 130103 China
- 3State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun Jilin 130022 China
Abstract
Herein, six cyclometalated Ir(iii) complexes have been systematically designed and investigated via density functional theory (DFT) and time-dependent DFT (TD-DFT) to unravel the effects of geometric and regional isomerism on the optoelectronic properties of organic electroluminescent materials. The complexes comprise three isomers each of Ir(tfmppy)2(tpip) and Ir(ptfmpy)2(tpip), where tfmppy = 2-[4-(trifluoromethyl)phenyl]pyridine, ptfmpy = 2-fluoro-5-trifluoromethylpyridine, and tpip = tetraphenylimidodiphosphate. Geometric isomerism arises from the cis/trans configurations of N and C donor atoms in the two C^N chelating ligands, whereas regional isomerism stems from different substitution positions of the trifluoromethyl group on the phenylpyridine main ligand. Comprehensive calculations of geometric structures, absorption and emission spectra, frontier molecular orbitals (FMOs), spin–orbit coupling (SOC) constants, and a series of radiative and non-radiative rate constants reveal that geometric isomerism modulates the FMO energy gap by altering the spatial arrangement of ligands around the Ir metal center, thereby tuning the emission energy and wavelength through modifications of the microscopic electronic structure. Regional isomerism fine-tunes the FMO energy levels via substituent positional variations on the ligand framework, significantly influencing the absorption spectral profiles and optical bandgap. Analysis of spin–orbit coupling and key rate constants reveals that the studied complexes are predominantly phosphorescent emitters, with complex 6 showing a certain tendency towards thermally activated delayed fluorescence (TADF). This work may provide a theoretical reference for experimental synthesis, and the relevant luminescent materials are expected to find applications in OLEDs, thereby supporting their subsequent use in organic electroluminescence.
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BibTeX
@article{qin2026effects,
title = {{Effects of geometric isomerism and regioisomerism on photophysical properties of iridium(iii) complexes}},
author = {Zheng-Kun Qin and Si-Tong Liu and Yi-Xuan Liu and Yu-Xin Zhang and Jia-He Zuo and Shuai Chen and Yun-Long Sun and Ming-Xing Song},
journal = {RSC Advances},
year = {2026},
month = oct,
doi = {10.1039/d6ra07317d},
url = {https://doi.org/10.1039/d6ra07317d},
note = {CC BY-NC 3.0},
}
RIS
TY - JOUR
TI - Effects of geometric isomerism and regioisomerism on photophysical properties of iridium(iii) complexes
AU - Zheng-Kun Qin
AU - Si-Tong Liu
AU - Yi-Xuan Liu
AU - Yu-Xin Zhang
AU - Jia-He Zuo
AU - Shuai Chen
AU - Yun-Long Sun
AU - Ming-Xing Song
PY - 2026
DA - 2026/10/09
JO - RSC Advances
DO - 10.1039/d6ra07317d
UR - https://doi.org/10.1039/d6ra07317d
AB - Herein, six cyclometalated Ir(iii) complexes have been systematically designed and investigated via density functional theory (DFT) and time-dependent DFT (TD-DFT) to unravel the effects of geometric and regional isomerism on the optoelectronic properties of organic electroluminescent materials. The complexes comprise three isomers each of Ir(tfmppy)2(tpip) and Ir(ptfmpy)2(tpip), where tfmppy = 2-[4-(trifluoromethyl)phenyl]pyridine, ptfmpy = 2-fluoro-5-trifluoromethylpyridine, and tpip = tetraphenylimidodiphosphate. Geometric isomerism arises from the cis/trans configurations of N and C donor atoms in the two C^N chelating ligands, whereas regional isomerism stems from different substitution positions of the trifluoromethyl group on the phenylpyridine main ligand. Comprehensive calculations of geometric structures, absorption and emission spectra, frontier molecular orbitals (FMOs), spin–orbit coupling (SOC) constants, and a series of radiative and non-radiative rate constants reveal that geometric isomerism modulates the FMO energy gap by altering the spatial arrangement of ligands around the Ir metal center, thereby tuning the emission energy and wavelength through modifications of the microscopic electronic structure. Regional isomerism fine-tunes the FMO energy levels via substituent positional variations on the ligand framework, significantly influencing the absorption spectral profiles and optical bandgap. Analysis of spin–orbit coupling and key rate constants reveals that the studied complexes are predominantly phosphorescent emitters, with complex 6 showing a certain tendency towards thermally activated delayed fluorescence (TADF). This work may provide a theoretical reference for experimental synthesis, and the relevant luminescent materials are expected to find applications in OLEDs, thereby supporting their subsequent use in organic electroluminescence.
SN - 2046-2069
ER -