Color tuning of cyclometalated 2-phenylbenzo[d]oxazole-based iridium(III) complexes through modification of different N^O ancillary ligands

Li, Gao‐Nan; Gao, Cheng-Wei; Chen, Hao-Hua; Chen, Tingting; Xie, Hongmei; Lin, Shuai; Sun, Wei; Chen, Guang‐Ying; Niu, Zhi‐Gang

doi:10.1016/j.ica.2016.02.009

Cited by 7 publications

(3 citation statements)

References 42 publications

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“…Meanwhile, the emission spectra are broad and structureless, indicating that the emissive excited states are dominantly the 3 MLCT character. 27,28 It should be noted that the emission wavelengths for 1, 4, and 7 are red-shifted relative to other series of complexes 2−3, 5−6, and 8−9, respectively. Moreover, complex 4 exhibits emission spectra even more red shifted in comparison to the other complexes (1 and 7) of the series.…”

Section: ■ Results and Discussionmentioning

confidence: 95%

Orange-Red Phosphorescent Iridium(III) Complexes Bearing Bisphosphine Ligands: Synthesis, Photophysical and Electrochemical Properties, and DFT Calculations

Dou

Zheng

et al. 2017

Organometallics

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Nine new phosphorus-coordinated iridium(III) complexes of the form [Ir(C∧N)2(P∧P)]PF6, [Ir(F-piq)2(xantphos)]PF6 (1), [Ir(F-piq)2(binap)]PF6 (2), [Ir(F-piq)2(dppp)]PF6 (3), [Ir(Me-piq)2(xantphos)]PF6 (4), [Ir(Me-piq)2(binap)]PF6 (5), [Ir(Me-piq)2(dppp)]PF6 (6), [Ir(CF3O-piq)2(xantphos)]PF6 (7), [Ir(CF3O-piq)2(binap)]PF6 (8), and [Ir(CF3O-piq)2(dppp)]PF6 (9) (F-piq = 1-(4-fluorophenyl)isoquinoline, Me-piq = 1-(p-tolyl)isoquinoline, CF3O-piq = 1-(4-(trifluoromethoxy)phenyl)isoquinoline, xantphos = 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene, binap = 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, dppp = 1,3-bis(diphenylphosphanyl)propane), have been synthesized and fully characterized. The crystal structures of 1, 7, and 9 have been determined by X-ray analysis. The most representative molecular orbital energy-level diagrams and the lowest energy electronic transitions of 1–9 have been calculated with density functional theory (DFT) and time-dependent DFT (TD-DFT). All of the complexes are orange-red emissive with quantum efficiencies of 3.2–24.4% and lifetimes of 1.77–3.19 μs in degassed CH2Cl2 solution at room temperature. These research results reveal that the Me-piq C∧N ligand and xantphos P∧P ligand are beneficial for a red shift of absorption and emission wavelength. Complex 4 has better charge transfer ability, which probably promises its use as a red-phosphorescent material.

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Section: ■ Results and Discussionmentioning

confidence: 95%

Orange-Red Phosphorescent Iridium(III) Complexes Bearing Bisphosphine Ligands: Synthesis, Photophysical and Electrochemical Properties, and DFT Calculations

Dou

Zheng

et al. 2017

Organometallics

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“…They exhibited a wide range of emission wavelengths (λ max = 531-598 nm) with high quantum yields (19%-94%). 12 The research findings showed that the structures of ancillary ligands have obvious effect on tuning the emission color of bobased iridium(III) complexes. Therefore, we wanted to further investigate other types of ancillary ligands.…”

Section: Introductionmentioning

confidence: 97%

Cyclometalated Iridium(III) Complexes Containing 2-Phenylbenzo[d]oxazole Ligand: Synthesis, X-ray Crystal Structures, Properties and DFT Calculations

Yang

Zhang

Zuo³

et al. 2019

ACSi

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Two new iridium(III) complexes were synthesized and fully characterized, [(bo) 2 Ir(pzpy)] (2a) and [(bo) The single crystal structures of 2a-2b have been determined. Considering the relationship between their structures and photophysical properties, DFT calculations have been used to further support this inference. These Ir(III) complexes emit from the excited state of 3 MLCT/ 3 LLCT in the green and yellow region, and the quantum yields in the degassed CH 2 Cl 2 solution at room temperature are 35.2% and 46.1%. Theoretical and experimental results show that iridium(III) complexes 2a-2b are promising phosphorescent material.

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“…[11][12][13] This interest is largely due to the possibility to fine-tune their photophysical properties depending on subtle electronic modifications on the π-conjugated backbone of the ligands coordinated to the metal. [14][15][16][17] Indeed, cyclometalated complexes have been shown to feature a strong interplay between the molecular orbitals of the ancillary ligands and those of the metallic center, leading to either Metal-to-Ligand Charge Transfer (MLCT) or Ligand-to-Ligand Charge Transfer (LLCT) intense transitions. Electronic modifications around the trivalent iridium ion can indeed lead to drastic optical parameter changes such as absorption and/or emission maximum wavelength, phosphorescent quantum yield or excited-state lifetime.…”

Section: Introductionmentioning

confidence: 99%

Phosphorescent Cyclometalated Iridium(III) Complexes Bearing Ethynyl‐Extended 2‐(2'‐Hydroxyphenyl) Benzoxazole Ancillary Ligands

et al. 2020

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This article describes the synthesis and full photophysical studies at room and low temperature of a series of iridium(III) complexes incorporating an ethynyl-extended benzoxazole-based ancillary ligand. The electronic nature of the terminal end-group of the ancillary ligand was modulated by the simple introduction of electron-donating (Me, NBu 2 ) or -withdrawing (CN) groups. For all complexes, TD-DFT calculations showed that the lowest-lying transition was ligand-centered [a] Dr.Scheme 2. Synthesis of cyclometalated iridium(III) complexes 4-6 and 7-9. Results and Discussion SynthesisThe synthesis of the cyclometalated iridium(III) complexes 4-6 and 7-9 is presented on Scheme 2. The synthetic targets can be obtained straightforwardly in one step, starting from the previously reported 2-(2′-hydroxyphenyl)benzoxazole (HBO) ligands 1-3, [29] respectively functionalized by p-ethynyl-tolyl (R = Me), p-ethynyl-phenyl-N-dibutylamino (R = NBu 2 ) or p-ethynylbenzonitrile (R = CN) groups. The formation of the targeted cyclometalated iridium(III) complexes can be readily achieved by reacting the iridium(III) chloro-bridged dimers precursors A or B with two equivalents of HBO chelates 1-3, in the presence of an excess of potassium carbonate in a mixture of methanol and dichloromethane at 40°C (Scheme 2). Pure iridium(III) complexes were obtained in 47-72 % yield after purification on a silica gel column chromatography. All dimers were characterized with 1 H-NMR spectroscopy and high-resolution mass spectrometry (HR-MS), reflecting their molecular structure in each case. Formation of the targeted complexes 4-6 and 7-9 was notably confirmed by assessing the disappearance of the downfield H-bonded phenolic proton present in the molecular structure of starting HBO ligands 1-3 by 1 H-NMR spectroscopy. All spectra can be found in the Supporting Information (SI). As reported for other similar Ir (III) cyclometalated complexes, it is expected that complexes 4-9 adopt a distorted octahedral geometry with the nitrogen atoms of the pyridine moiety in trans position. [30] Absorption Absorption spectra of HBO ligands 1-3 and iridium(III) heteroleptic complexes 4-9, recorded in acetonitrile solution at room column chromatography on SiO 2 eluting with CH 2 Cl 2 /pet. ether to yield complexes 4-9 as yellow powders in 47-72 % yield. Complex 4: Yellow powder. 58 %. 1 H-NMR (400 MHz, CDCl 3 ) δ (ppm) = 8.74 (d, 1H, CH Ar, J = 5.2 Hz), 8.14 (d, 1H, CH Ar, J = 2.4 Hz), 8.02 (d, 1H, CH Ar, J = 5.6 Hz), 7.79 (d, 1H, CH Ar, J = 8 Hz), 7.72 (d, 1H, CH Ar, J = 8 Hz), 7.51-7.60 (m, 4H, CH Ar), 7.37 (d, 1H, CH Ar, J = 8 Hz), 7.32 (d, 2H, CH Ar, J = 8 Hz), 7.23 (dd, 1H, CH Ar, J = 9 Hz), 7.05-7.08 (m, 3H, CH Ar), 6.97 (t, 1H, CH Ar, J = 6 Hz), 6.68-6.87 (m, 6H, CH Ar), 6.62 (d, 1H, CH Ar, J = 9.2 Hz), 6.40 (d, 1H, CH Ar, J = 7.6 Hz), 6.11 (d, 1H, CH Ar, J = 7.6 Hz), 6.01 (d, 1H, CH Ar, J = 8.4 Hz), 2.28 (s, 3H, CH 3 ). ESI-HRMS: calcd. for C 44 H 31 IrN 3 O 2 [M + H] 826.2043, found [M + H] 826.2052. Complex 5: Yellow powder. 72 %. 1 H-NMR (400 MHz, ...

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Color tuning of cyclometalated 2-phenylbenzo[d]oxazole-based iridium(III) complexes through modification of different N^O ancillary ligands

Cited by 7 publications

References 42 publications

Orange-Red Phosphorescent Iridium(III) Complexes Bearing Bisphosphine Ligands: Synthesis, Photophysical and Electrochemical Properties, and DFT Calculations

Orange-Red Phosphorescent Iridium(III) Complexes Bearing Bisphosphine Ligands: Synthesis, Photophysical and Electrochemical Properties, and DFT Calculations

Cyclometalated Iridium(III) Complexes Containing 2-Phenylbenzo[d]oxazole Ligand: Synthesis, X-ray Crystal Structures, Properties and DFT Calculations

Phosphorescent Cyclometalated Iridium(III) Complexes Bearing Ethynyl‐Extended 2‐(2'‐Hydroxyphenyl) Benzoxazole Ancillary Ligands

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