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Davidson R, Hsu YT, Fox MA, Aguilar JA, Yufit D, Beeby A. Tuning Emission Lifetimes of Ir(C^N) 2(acac) Complexes with Oligo(phenyleneethynylene) Groups. Inorg Chem 2023; 62:2793-2805. [PMID: 36705986 PMCID: PMC9930119 DOI: 10.1021/acs.inorgchem.2c03934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Emissive compounds with long emission lifetimes (μs to ms) in the visible region are of interest for a range of applications, from oxygen sensing to cellular imaging. The emission behavior of Ir(ppy)2(acac) complexes (where ppy is the 2-phenylpyridyl chelate and acac is the acetylacetonate chelate) with an oligo(para-phenyleneethynylene) (OPE3) motif containing three para-rings and two ethynyl bridges attached to acac or ppy is examined here due to the accessibility of the long-lived OPE3 triplet states. Nine Ir(ppy)2(acac) complexes with OPE3 units are synthesized where the OPE3 motif is at the acac moiety (aOPE3), incorporated in the ppy chelate (pOPE3) or attached to ppy via a durylene link (dOPE3). The aOPE3 and dOPE3 complexes contain OPE3 units that are decoupled from the Ir(ppy)2(acac) core by adopting perpendicular ring-ring orientations, whereas the pOPE3 complexes have OPE3 integrated into the ppy ligand to maximize electronic coupling with the Ir(ppy)2(acac) core. While the conjugated pOPE3 complexes show emission lifetimes of 0.69-32.8 μs similar to the lifetimes of 1.00-23.1 μs for the non-OPE3 Ir(ppy)2(acac) complexes synthesized here, the decoupled aOPE3 and dOPE3 complexes reveal long emission lifetimes of 50-625 μs. The long lifetimes found in aOPE3 and dOPE3 complexes are due to intramolecular reversible electronic energy transfer (REET) where the long-lived triplet-state metal to ligand charge transfer (3MLCT) states exchange via REET with the even longer-lived triplet-state localized OPE3 states. The proposed REET process is supported by changes observed in excitation wavelength-dependent and time-dependent emission spectra from aOPE3 and dOPE3 complexes, whereas emission spectra from pOPE3 complexes remain independent of the excitation wavelength and time due to the well-established 3MLCT states of many Ir(ppy)2(acac) complexes. The long lifetimes, visible emission maxima (524-526 nm), and photoluminescent quantum yields of 0.44-0.60 for the dOPE3 complexes indicate the possibility of utilizing such compounds in oxygen-sensing and cellular imaging applications.
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Edkins RM, Hsu YT, Fox MA, Yufit D, Beeby A, Davidson RJ. Divergent Approach for Tris-Heteroleptic Cyclometalated Iridium Complexes Using Triisopropylsilylethynyl-Substituted Synthons. Organometallics 2022; 41:2487-2493. [PMID: 36118103 PMCID: PMC9477230 DOI: 10.1021/acs.organomet.2c00292] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Indexed: 11/29/2022]
Abstract
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Bis-heteroleptic cyclometalated iridium
complexes
of the form Ir(La)2(acac), where La is a substituted 2-phenylpyridine derivative and acac is an acetylacetonato
ligand, are a useful class of luminescent organometallic complexes
for a range of applications. Related tris-heteroleptic
complexes of the form Ir(La)(Lb)(acac) offer
the potential advantage of greater functionality through the use of
two different cyclometalated ligands but are, in general, more difficult
to obtain. We report the synthesis of divergent bis- and tris-heteroleptic triisopropylsilylethynyl-substituted
intermediate complexes that can be diversified using a “chemistry-on-the-complex”
approach. We demonstrate the methodology through one-pot deprotection
and Sonogashira cross-coupling of the intermediate complexes with para-R-aryliodides (R = H, SMe, and CN). The photophysical
and electrochemical behaviors of the resultant bis- and tris-heteroleptic complexes are compared,
and it is shown that the tris-heteroleptic complexes
exhibit subtly different emission and redox properties to the bis-heteroleptic complexes, such as further red-shifted
emission maxima and lower extinction coefficients, which can be attributed
to the reduced symmetry. It is demonstrated, supported by DFT and
time-dependent DFT calculations, that the charge-transfer character
of the emission can be altered via variation of the terminal substituent;
the introduction of an electron-withdrawing cyano group in the terminal
position leads to a significant red shift, while the introduction
of an SMe group can substantially increase the emission quantum yield.
Most notably, this convenient synthetic approach reduces the need
to perform the often challenging isolation of tris-heteroleptic complexes to a single divergent intermediate, which
will simplify access to families of complexes of the form Ir(La)(Lb)(acac).
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Affiliation(s)
- Robert M. Edkins
- WestCHEM Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, U.K
| | - Yu-Ting Hsu
- Department of Chemistry, University of Durham, South Road, England, Durham DH1 3LE, U.K
| | - Mark A. Fox
- Department of Chemistry, University of Durham, South Road, England, Durham DH1 3LE, U.K
| | - Dmitry Yufit
- Department of Chemistry, University of Durham, South Road, England, Durham DH1 3LE, U.K
| | - Andrew Beeby
- Department of Chemistry, University of Durham, South Road, England, Durham DH1 3LE, U.K
| | - Ross J. Davidson
- Department of Chemistry, University of Durham, South Road, England, Durham DH1 3LE, U.K
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Pander P, Daniels R, Zaytsev AV, Horn A, Sil A, Penfold TJ, Williams JAG, Kozhevnikov VN, Dias FB. Exceptionally fast radiative decay of a dinuclear platinum complex through thermally activated delayed fluorescence. Chem Sci 2021; 12:6172-6180. [PMID: 33996015 PMCID: PMC8098751 DOI: 10.1039/d1sc00160d] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/19/2021] [Indexed: 12/13/2022] Open
Abstract
A novel dinuclear platinum(ii) complex featuring a ditopic, bis-tetradentate ligand has been prepared. The ligand offers each metal ion a planar O^N^C^N coordination environment, with the two metal ions bound to the nitrogen atoms of a bridging pyrimidine unit. The complex is brightly luminescent in the red region of the spectrum with a photoluminescence quantum yield of 83% in deoxygenated methylcyclohexane solution at ambient temperature, and shows a remarkably short excited state lifetime of 2.1 μs. These properties are the result of an unusually high radiative rate constant of around 4 × 105 s-1, a value which is comparable to that of the very best performing Ir(iii) complexes. This unusual behaviour is the result of efficient thermally activated reverse intersystem crossing, promoted by a small singlet-triplet energy difference of only 69 ± 3 meV. The complex was incorporated into solution-processed OLEDs achieving EQEmax = 7.4%. We believe this to be the first fully evidenced report of a Pt(ii) complex showing thermally activated delayed fluorescence (TADF) at room temperature, and indeed of a Pt(ii)-based delayed fluorescence emitter to be incorporated into an OLED.
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Affiliation(s)
- Piotr Pander
- Department of Physics, Durham University South Road Durham DH1 3LE UK
| | - Ruth Daniels
- Department of Applied Sciences, Northumbria University Ellison Building Newcastle upon Tyne NE1 8ST UK
| | - Andrey V Zaytsev
- Department of Applied Sciences, Northumbria University Ellison Building Newcastle upon Tyne NE1 8ST UK
| | - Ashleigh Horn
- Department of Applied Sciences, Northumbria University Ellison Building Newcastle upon Tyne NE1 8ST UK
| | - Amit Sil
- Department of Chemistry, Durham University South Road Durham DH1 3LE UK
| | - Thomas J Penfold
- Chemistry - School of Natural and Environmental Sciences, Newcastle University Newcastle upon Tyne NE1 7RU UK
| | | | - Valery N Kozhevnikov
- Department of Applied Sciences, Northumbria University Ellison Building Newcastle upon Tyne NE1 8ST UK
| | - Fernando B Dias
- Department of Physics, Durham University South Road Durham DH1 3LE UK
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4
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Affiliation(s)
- Pavel K. Mykhailiuk
- Enamine Ltd., Chervonotkatska 78, 02094 Kyiv, Ukraine
- Chemistry Department, Taras Shevchenko National University of Kyiv, Volodymyrska 64, 01601 Kyiv, Ukraine
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Lee S, Han WS. Cyclometalated Ir(iii) complexes towards blue-emissive dopant for organic light-emitting diodes: fundamentals of photophysics and designing strategies. Inorg Chem Front 2020. [DOI: 10.1039/d0qi00001a] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The fundamental photophysics of cyclometalated Ir(iii) complexes and surveys design strategies for efficient blue phosphorescent Ir(iii) complexes are summarised.
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Affiliation(s)
- Sunhee Lee
- Department of Chemistry
- Seoul Women's University
- Seoul 01797
- Republic of Korea
| | - Won-Sik Han
- Department of Chemistry
- Seoul Women's University
- Seoul 01797
- Republic of Korea
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Kim JH, Kim SY, Jang S, Yi S, Cho DW, Son HJ, Kang SO. Blue Phosphorescence with High Quantum Efficiency Engaging the Trifluoromethylsulfonyl Group to Iridium Phenylpyridine Complexes. Inorg Chem 2019; 58:16112-16125. [DOI: 10.1021/acs.inorgchem.9b02672] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Jin-Hyoung Kim
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
| | - So-Yoen Kim
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
| | - Seol Jang
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
| | - Seungjun Yi
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
| | - Dae Won Cho
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
| | - Ho-Jin Son
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
| | - Sang Ook Kang
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
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Sun Y, Yang X, Feng Z, Liu B, Zhong D, Zhang J, Zhou G, Wu Z. Highly Efficient Deep-Red Organic Light-Emitting Devices Based on Asymmetric Iridium(III) Complexes with the Thianthrene 5,5,10,10-Tetraoxide Moiety. ACS APPLIED MATERIALS & INTERFACES 2019; 11:26152-26164. [PMID: 31265247 DOI: 10.1021/acsami.9b06749] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Highly efficient deep-red organic light-emitting devices (OLEDs) are indispensable for developing high-performance red-green-blue (RGB) displays and white OLEDs (WOLEDs). However, the shortage of deep-red emitters with high photoluminescence quantum yields (PLQYs) and balanced charge injection/transport abilities has severely restricted the performance of deep-red OLEDs. Herein, we design and synthesize four efficient emitters by combining the isoquinoline group with the thianthrene 5,5,10,10-tetraoxide group. Benefited from the introduction of the thianthrene 5,5,10,10-tetraoxide group, these Ir(III) complexes show improved electron-injection/-transport abilities. By enhancing the contribution of the triplet metal-to-ligand charge transfer (3MLCT) in emissions, the asymmetric configuration endows the related deep-red Ir(III) complexes with high PLQYs of 0.45-0.50 in solutions. More importantly, PLQYs of these Ir(III) complexes in doped host films increase up to 0.91, which is much higher than PLQYs reported for conventional deep-red Ir(III) complexes with impressive electroluminescent performance. As a result, solution-processed OLEDs based on these Ir(III) complexes exhibit deep-red emissions with Commission Internationale de L'Eclairage (CIE x, y) coordinates very close to the National Television System Committee (NTSC)-recommended standard red CIE coordinates of (0.67, 0.33). Furthermore, a deep-red OLED using the asymmetric Ir(III) complex SOIrOPh as the emitter shows outstanding performance with a peak external quantum efficiency (EQE) of 25.8%, which is the highest EQE reported for solution-processed deep-red OLEDs. This work sheds light on the great potential of utilizing the thianthrene 5,5,10,10-tetraoxide group to develop phosphorescent emitters for highly efficient OLEDs.
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Guo J, Pan X, Li J, Wu W, Zhang J. Theoretical investigation of the vibronic phosphorescence spectra and quantum yields for iridium(III) complexes with 2-(2,5,2',3',4',5',6'-heptafluoro-biphenyl-4-yl)-pyridine as the primary ligand. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 216:179-189. [PMID: 30897379 DOI: 10.1016/j.saa.2019.03.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 03/06/2019] [Accepted: 03/06/2019] [Indexed: 06/09/2023]
Abstract
Cyclometalated Ir(III) complexes are widely used as phosphorescent materials in organic light-emitting diodes. In this work, the vibrationally resolved phosphorescence spectra of an experimental reported and four novel designed Ir(III) complexes with 2-(2,5,2',3',4',5',6'-heptafluoro-biphenyl-4-yl)-pyridine (HFYP) as primary ligand are investigated by theoretical calculations. The ancillary ligands are 3-(pentafluorophenyl)-pyridin-2-yl-1,2,4-triazolate (exp3), 3-(trifluoromethyl)-pyridin-2-yl-1,2,4-triazolate (5), 5-methylsulfonyl-2-oxyphenyl-2-oxazole (6), 5-trifluoromethyl-2-oxyphenyl-2-oxazole (7), 2-(3-(trifluoromethyl)-1H-1,2-diazol-5-yl)pyridine (8), respectively. Phosphorescence spectra show that there are mainly two strong peaks, which can be ascribed as low-frequency vibrational modes such as the rotation of ligand plane, and benzene ring/pyridine ring in ligand HFYP1 skeleton vibration coupled with CH in pyridine ring in plane bending vibration. The phosphorescence quantum yields were quantitatively determined by evaluating radiative decay rate constant kr, intersystem crossing rate constatant kISC and temperature-dependent nonradiative decay rate constant knr(T). It shows that the quantum yields of compounds exp3, 5 and 8 are relative higher, while those of compounds 6 and 7 are much smaller. This is mainly caused by larger knr(T) of compounds 6 and 7. It is anticipated that in Ir(III) complex with HFYP primary ligand, pyridin-2-yl-1,2,4-triazolate, 1,2-diazol-5-yl-pyridine are good ancillary ligand, while 2'-oxyphenyl-2-oxazoline is not appropriate to be ancillary ligand.
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Affiliation(s)
- Jiayi Guo
- Henan Provincial Engineering Research Center of Green Anticorrosion Technology for Magnesium Alloy, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, People's Republic of China
| | - Xiao Pan
- Henan Provincial Engineering Research Center of Green Anticorrosion Technology for Magnesium Alloy, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, People's Republic of China
| | - Junfeng Li
- Henan Provincial Engineering Research Center of Green Anticorrosion Technology for Magnesium Alloy, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, People's Republic of China.
| | - Wenpeng Wu
- Henan Provincial Engineering Research Center of Green Anticorrosion Technology for Magnesium Alloy, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, People's Republic of China.
| | - Jinglai Zhang
- Henan Provincial Engineering Research Center of Green Anticorrosion Technology for Magnesium Alloy, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, People's Republic of China.
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9
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Grzelak I, Orwat B, Kownacki I, Hoffmann M. Quantum-chemical studies of homoleptic iridium(III) complexes in OLEDs: fac versus mer isomers. J Mol Model 2019; 25:154. [DOI: 10.1007/s00894-019-4035-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 04/15/2019] [Indexed: 01/19/2023]
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10
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Henwood AF, Antón-García D, Morin M, Rota Martir D, Cordes DB, Casey C, Slawin AMZ, Lebl T, Bühl M, Zysman-Colman E. Conjugated, rigidified bibenzimidazole ancillary ligands for enhanced photoluminescence quantum yields of orange/red-emitting iridium(iii) complexes. Dalton Trans 2019; 48:9639-9653. [DOI: 10.1039/c9dt00423h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A family of six orange/red-emitting cationic iridium complexes were synthesized and their optoelectronic properties comprehensively characterized.
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11
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Congrave DG, Batsanov AS, Du M, Liu Y, Zhu D, Bryce MR. Intramolecular π–π Interactions with a Chiral Auxiliary Ligand Control Diastereoselectivity in a Cyclometalated Ir(III) Complex. Inorg Chem 2018; 57:12836-12849. [DOI: 10.1021/acs.inorgchem.8b02034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daniel G. Congrave
- Department of Chemistry, Durham University, South Road, Durham DH1 3LE, U.K
| | - Andrei S. Batsanov
- Department of Chemistry, Durham University, South Road, Durham DH1 3LE, U.K
| | - Mingxu Du
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, People’s Republic of China
| | - Yu Liu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, People’s Republic of China
| | - Dongxia Zhu
- Key Laboratory of Nanobiosensing and Nanobioanalysis at Universities of Jilin Province, Department of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun, Jilin 130024, People’s Republic of China
| | - Martin R. Bryce
- Department of Chemistry, Durham University, South Road, Durham DH1 3LE, U.K
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Kumar S, Surati KR, Lawrence R, Vamja AC, Yakunin S, Kovalenko MV, Santos EJ, Shih CJ. Design and Synthesis of Heteroleptic Iridium(III) Phosphors for Efficient Organic Light-Emitting Devices. Inorg Chem 2017; 56:15304-15313. [DOI: 10.1021/acs.inorgchem.7b02872] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sudhir Kumar
- Institute for Chemical and Bioengineering,
ETH Zurich, 8093 Zurich, Switzerland
| | - K. R. Surati
- Department of Chemistry, Sardar Patel University, Vallabh Vidyanagar, Gujarat India
| | - Robert Lawrence
- School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN, United Kingdom
| | - Atul C. Vamja
- Department of Chemistry, Sardar Patel University, Vallabh Vidyanagar, Gujarat India
| | - Sergii Yakunin
- Laboratory of Inorganic Chemistry, ETH Zurich, 8093 Zurich, Switzerland
- Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Maksym V. Kovalenko
- Laboratory of Inorganic Chemistry, ETH Zurich, 8093 Zurich, Switzerland
- Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Elton J.G. Santos
- School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN, United Kingdom
| | - Chih-Jen Shih
- Institute for Chemical and Bioengineering,
ETH Zurich, 8093 Zurich, Switzerland
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