A computational study on second-order nonlinear optical properties based on bis-cyclometalated Ir(iii ) complexes: redox and substituent effects
| Autor: | Yao Yao, Yang Shen, Yu Chen, Yuan Zhang, Yong-Qing Qiu, Yuanyuan Zhao |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Valence (chemistry)
Absorption spectroscopy 010405 organic chemistry Chemistry Ligand Substituent Ionic bonding General Chemistry 010402 general chemistry 01 natural sciences Redox Catalysis 0104 chemical sciences chemistry.chemical_compound Crystallography Materials Chemistry Density functional theory Carbene |
| Zdroj: | New Journal of Chemistry. 45:10725-10734 |
| ISSN: | 1369-9261 1144-0546 |
| DOI: | 10.1039/d1nj01766g |
| Popis: | A series of neutral Ir(III) complexes that possess cyclometalated ligands (C^N) and different ancillary ligands, N-heterocyclic carbene (NHC) (R1 = H and R2 = H for complex 1, R1 = NO2 and R2 = H for complex 2, R1 = N(CH3)2 and R2 = H for complex 3, R1 = H and R2 = NO2 for complex 4, and R1 = H and R2 = N(CH3)2 for complex 5) and their ionic complexes 1+/−–5+/− have been investigated using density functional theory. The effects caused by different electron-withdrawing/donating substituents and electronic valence states on their geometries, electronic structures, UV-vis absorption spectra, and second-order nonlinear optical (NLO) properties were explored. The results show that the geometries of these complexes are slightly affected by the variation of the ancillary ligand and the electronic valence state. A significant impact on absorption spectra and second-order NLO properties is observed during the redox process of the neutral complexes. The absorption spectrum has a remarkable red-shift for ionic complexes 1+/−–5+/− compared with their neutral complexes. The obtained βtot values of complexes 1+/−–5+/− range from 7289.2 to 20753.9 a.u., while the value is only 1395.9 a.u. for neutral complex 1. The dramatic enhancement of NLO response is mainly ascribed to the charge redistribution and the variation of transition energy caused by the loss/gain of an electron. Among five neutral complexes, complex 4 presents a high βtot value, 7019.3 a.u. This illustrates that the introduction of a strong electron-withdrawing group in R2 of ancillary ligands promotes the second-order NLO response for this type of cyclometalated Ir(III) complex. This work will be beneficial for designing high performance and excellent switchable NLO materials. |
| Databáze: | OpenAIRE |
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