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Kim H, Ryu CH, Hong M, Lee KM, Jo U, Kang Y. Blue Phosphorescent Pt(II) Compound Based on Tetradentate Carbazole/2,3'-Bipyridine Ligand and Its Application in Organic Light-Emitting Diodes. Molecules 2024; 29:2929. [PMID: 38930994 PMCID: PMC11206379 DOI: 10.3390/molecules29122929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/17/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
The tetradentate ligand, merging a carbazole unit with high triplet energy and dimethoxy bipyridine, renowned for its exceptional quantum efficiency in coordination with metals like Pt, is expected to demonstrate remarkable luminescent properties. However, instances of tetradentate ligands such as bipyridine-based pyridylcarbazole derivatives remain exceptionally scarce in the current literature. In this study, we developed a tetradentate ligand based on carbazole and 2,3'-bipyridine and successfully complexed it with Pt(II) ions. This novel compound (1) serves as a sky-blue phosphorescent material for use in light-emitting diodes. Based on single-crystal X-ray analysis, compound 1 has a distorted square-planar geometry with a 5/6/6 backbone around the Pt(II) core. Bright sky-blue emissions were observed at 488 and 516 nm with photoluminescent quantum yields of 34% and a luminescent lifetime of 2.6 μs. TD-DFT calculations for 1 revealed that the electronic transition was mostly attributed to the ligand-centered (LC) charge transfer transition with a small contribution from the metal-to-ligand charge transfer transition (MLCT, ~14%). A phosphorescent organic light-emitting device was successfully fabricated using this material as a dopant, along with 3'-di(9H-carbazol-9-yl)-1,1'-biphenyl (mCBP) and 9-(3'-carbazol-9-yl-5-cyano-biphenyl-3-yl)-9H-carbazole-3-carbonitrile (CNmCBPCN) as mixed hosts. A maximum quantum efficiency of 5.2% and a current efficiency of 15.5 cd/A were obtained at a doping level of 5%.
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Affiliation(s)
- Hakjo Kim
- Division of Science Education, Department of Chemistry, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Chan-Hee Ryu
- Division of Science Education, Department of Chemistry, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Miso Hong
- Division of Science Education, Department of Chemistry, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Kang Mun Lee
- Division of Science Education, Department of Chemistry, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Unhyeok Jo
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Youngjin Kang
- Division of Science Education, Department of Chemistry, Kangwon National University, Chuncheon 24341, Republic of Korea
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2
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Khistiaeva VV, Buss S, Eskelinen T, Hirva P, Kinnunen N, Friedel J, Kletsch L, Klein A, Strassert CA, Koshevoy IO. Cyanido-bridged diplatinum(ii) complexes: ligand and solvent effect on aggregation and luminescence. Chem Sci 2024; 15:4005-4018. [PMID: 38487239 PMCID: PMC10935663 DOI: 10.1039/d3sc06941a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Accepted: 01/23/2024] [Indexed: 03/17/2024] Open
Abstract
The association of platinum(ii)-based luminophores, which is caused by metal⋯metal and π-π stacking interactions, has been actively exploited in supramolecular construction of photofunctional molecular materials. Herein, we describe a series of bimetallic complexes [{Pt(C^N^/*N)}2(CN)][BAr4F], containing cyanido-bridged cyclometalated Pt(ii) chromophore fragments (HC^N^N = 6-phenyl-2,2'-bipyridine, (benzyltriazolyl)-phenylpyridine, and pyrazolyl-phenylpyridine; HC^N*N = N-pentyl-6-phenyl-N-(pyridin-2-yl)pyridin-2-amine; ^/* denote five/six-membered metallocycles). These compounds are intensely phosphorescent at room temperature showing quantum yields up to 0.73 in solution and 0.62 in the solid state, which are generally higher than those of the mononuclear relatives [Pt(C^N^/*N)(CN)]. The complex cations bearing sterically unhindered -C^N^N ligands readily assemble in solution, reaching the tetrameric species [{Pt(C^N^N)}2(CN)]44+ as suggested by diffusion NMR spectroscopy. The size of the aggregates can be regulated by the concentration, temperature, and polarity of the solvent that allows to alter the emission from green to near-IR. In the solid state, the maximum of low-energy luminescence is shifted up to 912 nm. The results show that photophysical properties of discrete complexes and the intermolecular aggregation can be substantially enhanced by utilizing the rigid bimetallic units giving rise to novel dynamic light emitting Pt(ii) systems.
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Affiliation(s)
- Viktoria V Khistiaeva
- Department of Chemistry, University of Eastern Finland P.O. Box 111 FI-80100 Joensuu Finland
| | - Stefan Buss
- Institut für Anorganische und Analytische Chemie, Universität Münster, CiMIC, CeNTech Heisenbergstraße 11 48149 Münster Germany
| | - Toni Eskelinen
- Department of Chemistry, University of Eastern Finland P.O. Box 111 FI-80100 Joensuu Finland
- Department of Chemistry and Materials Science, Aalto University FI-00076 Aalto Finland
| | - Pipsa Hirva
- Department of Chemistry, University of Eastern Finland P.O. Box 111 FI-80100 Joensuu Finland
| | - Niko Kinnunen
- Department of Chemistry, University of Eastern Finland P.O. Box 111 FI-80100 Joensuu Finland
| | - Joshua Friedel
- Faculty of Mathematics and Natural Sciences, Department of Chemistry and Biochemistry, Institute for Inorganic Chemistry, University of Cologne Greinstrasse 6 D-50939 Cologne Germany
| | - Lukas Kletsch
- Faculty of Mathematics and Natural Sciences, Department of Chemistry and Biochemistry, Institute for Inorganic Chemistry, University of Cologne Greinstrasse 6 D-50939 Cologne Germany
| | - Axel Klein
- Faculty of Mathematics and Natural Sciences, Department of Chemistry and Biochemistry, Institute for Inorganic Chemistry, University of Cologne Greinstrasse 6 D-50939 Cologne Germany
| | - Cristian A Strassert
- Institut für Anorganische und Analytische Chemie, Universität Münster, CiMIC, CeNTech Heisenbergstraße 11 48149 Münster Germany
| | - Igor O Koshevoy
- Department of Chemistry, University of Eastern Finland P.O. Box 111 FI-80100 Joensuu Finland
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3
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Zhang H, Liu C, Du C, Zhang B. Efficiently red emitting cycloplatinated(II) complexes supported by N^O and N^P benzimidazole ancillary ligands. J Organomet Chem 2022. [DOI: 10.1016/j.jorganchem.2021.122237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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4
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Stipurin S, Strassner T. C^C* Platinum(II) Complexes with Electron-Withdrawing Groups and Beneficial Auxiliary Ligands: Efficient Blue Phosphorescent Emission. Inorg Chem 2021; 60:11200-11205. [PMID: 34242510 DOI: 10.1021/acs.inorgchem.1c01172] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The combination of strong electron-withdrawing groups in cyclometalated N-heterocyclic carbene ligands (C^C*) with known beneficial auxiliary ligands in phosphorescent platinum(II) complexes leads to efficient light-to-deep-blue emission with quantum yields of up to 92%. All compounds were characterized and investigated regarding their photophysical, electrochemical, and thermal properties, and three complexes could additionally be characterized by solid-state structures. Density functional theory calculations (PBE0/6-311G* with dispersion correction) are reported.
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Affiliation(s)
- Sergej Stipurin
- Physikalische Organische Chemie, Technische Universität Dresden, 01069 Dresden, Germany
| | - Thomas Strassner
- Physikalische Organische Chemie, Technische Universität Dresden, 01069 Dresden, Germany
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5
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Gong ZL, Tang K, Zhong YW. A Carbazole-Bridged Biscyclometalated Diplatinum Complex: Synthesis, Characterization, and Dual-Mode Aggregation-Enhanced Phosphorescence. Inorg Chem 2021; 60:6607-6615. [PMID: 33861581 DOI: 10.1021/acs.inorgchem.1c00403] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A cationic carbazole-bridged biscyclometalated diplatinum complex 4 has been synthesized and characterized. Single-crystal X-ray analysis demonstrates that complex 4 displays a dimeric structure with noncovalent π-π stacking and unique double Pt-Pt interactions. In aerated dilute CH3CN, complex 4 is characterized by a very weak monomeric yellow emission (λemi = 547 nm; Φ = 0.51%), which is attributed to the triplet intraligand (3LC) excited state mixing with some charge transfer characters. In contrast, under aerated conditions, the dispersion of 4 in a mixed solvent of CH3CN/Et2O (1/9, v/v) or CH3CN/H2O (1/9, v/v) displays intense yellow (λemi = 550 nm; Φ = 35.5%; τ = 11.10 μs) and red emission (λemi = 635 nm; Φ = 14.1%; τ = 7.00 μs), respectively. These aggregation-induced phosphorescent emission enhancements are considered being caused by the oxygen-shielding effect and the molecular rigidification-induced decrease of nonradiative decays in the aggregate state. The morphology and size of the aggregates under these two conditions are examined by scanning electron microscope and dynamic light scattering analysis. The absorption and emission properties of 4 are further rationalized by time-dependent density functional theory calculations on a model compound.
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Affiliation(s)
- Zhong-Liang Gong
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Kun Tang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu-Wu Zhong
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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Matsudaira K, Mimura Y, Hotei J, Yagi S, Yamashita K, Fujiki M, Imai Y. Magnetic Circularly Polarized Luminescence from Pt
II
OEP and F
2
‐ppyPt
II
(acac) under North‐up and South‐up Faraday Geometries. Chem Asian J 2021; 16:926-930. [DOI: 10.1002/asia.202100172] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/09/2021] [Indexed: 01/22/2023]
Affiliation(s)
- Kana Matsudaira
- Department of Applied Chemistry Faculty of Science and Engineering Kindai University 3-4-1 Kowakae Higashi-Osaka Osaka 577-8502 Japan
| | - Yuki Mimura
- Department of Applied Chemistry Faculty of Science and Engineering Kindai University 3-4-1 Kowakae Higashi-Osaka Osaka 577-8502 Japan
| | - Junichi Hotei
- Department of Applied Chemistry Graduate School of Engineering Osaka Prefecture University 1-1 Gakuen-cho, Naka-ku Sakai Osaka 599-8531 Japan
| | - Shigeyuki Yagi
- Department of Applied Chemistry Graduate School of Engineering Osaka Prefecture University 1-1 Gakuen-cho, Naka-ku Sakai Osaka 599-8531 Japan
| | - Ken‐ichi Yamashita
- Department of Chemistry Graduate School of Science Osaka University 1-1 Machikaneyama Toyonaka Osaka 560-0043 Japan
| | - Michiya Fujiki
- Graduate School of Science and Technology Nara Institute of Science and Technology 8916-5 Takayama Ikoma Nara 630-0192 Japan
| | - Yoshitane Imai
- Department of Applied Chemistry Faculty of Science and Engineering Kindai University 3-4-1 Kowakae Higashi-Osaka Osaka 577-8502 Japan
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