Synthesis and photophysical properties of iridium(III) complexes with n-heterocyclic carbene ligands for light emitting diode application
This research aimed to synthesise iridium(III) complexes with N-heterocyclic carbene (NHC) ligands and investigate their photophysical properties. Complexes ofchlorobis(2,4-difluorophenylpyridine)(pyridyltriazole)iridium(III) (C1), bis(2,4-difluorophenylpyridine)(4-methylbenzylpyridyltr...
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| Format: | thesis |
| Language: | eng |
| Published: |
2020
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| Subjects: | |
| Online Access: | https://ir.upsi.edu.my/detailsg.php?det=6802 |
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| Summary: | This research aimed to synthesise iridium(III) complexes with N-heterocyclic carbene (NHC) ligands and investigate their photophysical properties. Complexes ofchlorobis(2,4-difluorophenylpyridine)(pyridyltriazole)iridium(III) (C1), bis(2,4-difluorophenylpyridine)(4-methylbenzylpyridyltriazole)iridium(III) ion (C2),bis(2,4-difluorophenylpyridine)(hexylpyridyltriazole)iridium(III) ion (C3) andbis(2,4-difluorophenylpyridine)(2,6-difluorobenzylpyridyltriazole)iridium(III) ion (C4) were synthesised by reaction between dichloro-bridged iridium(III) dimer,[Ir(2,4-F2ppy)2(-Cl)]2 and corresponding triazolium salts. Iridium(III) complexes werecharacterised by Carbon, Hydrogen, Nitrogen and Sulphur (CHNS) elemental analyser andspectroscopic techniques: H and C Nuclear Magnetic Resonance (NMR), FourierTransform-Infrared (FTIR) and Liquid Chromatography-Mass Spectrometry (LCMS). The molecularstructure of C1 was determined by single crystal X-Ray Diffraction (XRD) technique. The photophysical study was performed using spectroscopic techniques: Ultraviolet-Visible(UV-Vis) and fluorescence. The results of the IR spectra showed strong frequency bands in the at15951400 cm? were due to(C=N) and (C=C). The H NMR spectra displayed the proton signals of phenylpyridine and pyridinetriazole in the aromatic region between 5.00 and10.00 ppm. The C NMR spectra showed aromatic carbon signals in the range 80150 ppmand 050 ppm for aliphatic carbon that matches with the corresponding number ofcarbon atoms in C1C4. Complexes of C1, C2, C3 and C4 exhibited ESI spectra at m/z 754.22,823.17, 803.11 and 847.15, respectively. X-Ray crystallographic study confirmed iridium(III)ion in C1 was coordinated to one pyridine-triazole, one chloro and two difluorophenylpyridineligands in a distorted octahedral geometry. Steady- state emission spectroscopy demonstratedC1, C2, C3 and C4 emitted blue-green light in dichloromethane solution with an emission maximum at472 nm, 452 nm, 471 nm and 470 nm, respectively. In conclusion, electronic properties ofiridium(III) complexes with NHC ligands have tuned the lowest-unoccupied molecular orbital (LUMO)energy to the blue region. The implication of this study is these iridium(III) complexes can bestudied as an alternative material to enhance luminescence efficiency of organic light-emitting diode (OLED). |
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