1
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Wang X, Shi G, Wei R, Li M, Zhang Q, Zhang T, Chen CF, Hu HY. Fine-tuning of stable organic free-radical photosensitizers for photodynamic immunotherapy. Chem Sci 2024; 15:6421-6431. [PMID: 38699264 PMCID: PMC11062115 DOI: 10.1039/d3sc06826a] [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: 12/19/2023] [Accepted: 03/21/2024] [Indexed: 05/05/2024] Open
Abstract
Photodynamic immunotherapy (PDI) is an innovative approach to cancer treatment that utilizes photodynamic therapy (PDT) and photosensitizers (PSs) to induce immunogenic cell death (ICD). However, currently most commonly used PSs have restricted capabilities to generate reactive oxygen species (ROS) via a type-II mechanism under hypoxic environments, which limits their effectiveness in PDI. To overcome this, we propose a novel approach for constructing oxygen independent PSs based on stable organic free-radical molecules. By fine-tuning the characteristics of tris(2,4,6-trichlorophenyl)-methyl (TTM) radicals through the incorporation of electron-donating moieties, we successfully found that TTMIndoOMe could produce substantial amounts of ROS even in hypoxic environments. In vitro experiments showed that TTMIndoOMe could effectively produce O2˙-, kill tumor cells and trigger ICD. Moreover, in vivo experiments also demonstrated that TTMIndoOMe could further trigger anti-tumor immune response and exhibit a superior therapeutic effect compared with PDT alone. Our study offers a promising approach towards the development of next-generation PSs functioning efficiently even under hypoxic conditions and also paves the way for the creation of more effective PSs for PDI.
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Affiliation(s)
- Xiang Wang
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Gaona Shi
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Rao Wei
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Meng Li
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences Beijing 100190 China
| | - Qingyang Zhang
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Tiantai Zhang
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Chuan-Feng Chen
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences Beijing 100190 China
| | - Hai-Yu Hu
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
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2
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Mizuno A, Matsuoka R, Mibu T, Kusamoto T. Luminescent Radicals. Chem Rev 2024; 124:1034-1121. [PMID: 38230673 DOI: 10.1021/acs.chemrev.3c00613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Organic radicals are attracting increasing interest as a new class of molecular emitters. They demonstrate electronic excitation and relaxation dynamics based on their doublet or higher multiplet spin states, which are different from those based on singlet-triplet manifolds of conventional closed-shell molecules. Recent studies have disclosed luminescence properties and excited state dynamics unique to radicals, such as highly efficient electron-photon conversion in OLEDs, NIR emission, magnetoluminescence, an absence of heavy atom effect, and spin-dependent and spin-selective dynamics. These are difficult or sometimes impossible to achieve with closed-shell luminophores. This review focuses on luminescent organic radicals as an emerging photofunctional molecular system, and introduces the material developments, fundamental properties including luminescence, and photofunctions. Materials covered in this review range from monoradicals, radical oligomers, and radical polymers to metal complexes with radical ligands demonstrating radical-involved emission. In addition to stable radicals, transiently formed radicals generated in situ by external stimuli are introduced. This review shows that luminescent organic radicals have great potential to expand the chemical and spin spaces of luminescent molecular materials and thus broaden their applicability to photofunctional systems.
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Affiliation(s)
- Asato Mizuno
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Ryota Matsuoka
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, HayamaKanagawa 240-0193, Japan
| | - Takuto Mibu
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Tetsuro Kusamoto
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, HayamaKanagawa 240-0193, Japan
- JST-PRESTO, 4-1-8, Honcho, Kawaguchi, Saitama 332-0012, Japan
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
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3
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Saad HE, El-Reash GMA, Gaber M, Hashem MA, El-Reash YGA, Elamin NY, Elamin MR, El-Sayed YS. A novel isatin Schiff based cerium complex: synthesis, characterization, antimicrobial activity and molecular docking studies. BMC Genomics 2024; 25:162. [PMID: 38331729 PMCID: PMC10854109 DOI: 10.1186/s12864-024-10037-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 01/21/2024] [Indexed: 02/10/2024] Open
Abstract
In this work, a novel isatin-Schiff base L2 had been synthesized through a simple reaction between isatin and 2-amino-5-methylthio-1,3,4-thiadiazole. The produced Schiff base L2 was then subjected to a hydrothermal reaction with cerium chloride to produce the cerium (III)-Schiff base complex C2. Several spectroscopic methods, including mass spectra, FT-IR, elemental analysis, UV-vis, 13C-NMR, 1H-NMR, Thermogravimetric Analysis, HR-TEM, and FE-SEM/EDX, were used to completely characterize the produced L2 and C2. A computer simulation was performed using the MOE software program to find out the probable biological resistance of studied compounds against the proteins in some types of bacteria or fungi. To investigate the interaction between the ligand and its complex, we conducted molecular docking simulations using the molecular operating environment (MOE). The docking simulation findings revealed that the complex displayed greater efficacy and demonstrated a stronger affinity for Avr2 effector protein from the fungal plant pathogen Fusarium oxysporum (code 5OD4) than the original ligand. The antibacterial activity of the ligand and its Ce3+ complex were applied in vitro tests against different microorganism. The study showed that the complex was found to be more effective than the ligand.
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Affiliation(s)
- Heba E Saad
- Department of Chemistry, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Gaber M Abu El-Reash
- Department of Chemistry, Faculty of Science, Mansoura University, Mansoura, 35516, Egypt
| | - Mohamed Gaber
- Department of Chemistry, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Mohamed A Hashem
- Department of Chemistry, Faculty of Science, Mansoura University, Mansoura, 35516, Egypt.
| | - Yasmeen G Abou El-Reash
- Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), P.O. Box, 90950, 11623, Riyadh, Saudi Arabia
| | - Nuha Y Elamin
- Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), P.O. Box, 90950, 11623, Riyadh, Saudi Arabia
- Department of Chemistry, Sudan University of Science and Technology, P.O. Box 407, Khartoum, 11111, Sudan
| | - Mohamed R Elamin
- Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), P.O. Box, 90950, 11623, Riyadh, Saudi Arabia
| | - Yusif S El-Sayed
- Department of Chemistry, Faculty of Science, Tanta University, Tanta, 31527, Egypt
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4
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Fei LR, Wang J, Bai FQ, Wang SP, Hu B, Kong CP, Zhang HX. Investigating the influence of substituent groups in TTM based radicals for the excitation process: a theoretical study. Phys Chem Chem Phys 2023; 25:25871-25879. [PMID: 37725156 DOI: 10.1039/d3cp01248d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
Tri-(2,4,6-trichlorophenyl)methyl (TTM) based radicals can be promising in providing relatively high fluorescence quantum efficiency. In this study, we have evaluated the photoluminescence properties of a series of TTM-based radicals by means of DFT and TD-DFT methods. The optimized structures of the ground states (D0) and the first excited states (D1) of all the radicals are calculated and the computed emission bands are comparable with previous experimental results. knr is determined from transition dipole moments (μ12) and the energy gaps between D0 and D1 (ΔE), both of which can be regulated by the conjugated structures from the substituent groups. knr was derived from the mode-averaging method and is consistent with the experimental results. Factors influencing kr and knr, including the potential energy differences (ΔG0), the vibrational reorganization energies (λ) and the electron coupling term (Hab), are discussed. By comparing kr and knr in solvents with different polarities (cyclohexane, toluene, and chloroform), TTM based radicals in cyclohexane exhibit the most promising fluorescence efficiencies. Besides, two substituted radicals, namely 2Br-TTM-3PCz and 2F-TTM-3PCz, have been fabricated. The results show that fluorine atoms are able to increase ΔG0 and a considerably small knr has been predicted. We expect that our calculation can benefit the design of light-emitting molecules in further experiments.
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Affiliation(s)
- Lu-Ran Fei
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
| | - Jian Wang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
| | - Fu-Quan Bai
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
| | - Shi-Ping Wang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
| | - Bin Hu
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
| | - Chui-Peng Kong
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
| | - Hong-Xing Zhang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
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5
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Punzi A, Dai Y, Dibenedetto CN, Mesto E, Schingaro E, Ullrich T, Striccoli M, Guldi DM, Negri F, Farinola GM, Blasi D. Dark State of the Thiele Hydrocarbon: Efficient Solvatochromic Emission from a Nonpolar Centrosymmetric Singlet Diradicaloid. J Am Chem Soc 2023; 145:20229-20241. [PMID: 37671971 DOI: 10.1021/jacs.3c05251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
In this work, a comprehensive investigation of the photoinduced processes and mechanisms linked to the luminescence of a novel nonperchlorinated Thiele hydrocarbon (TTH) is presented. Despite the comparable diradical character of TTH (y0 = 0.32-0.44) and the unsubstituted Thiele hydrocarbon (TH) (y0 = 0.30), the polyhalogenated species is inert and photostable, showing an intense deep-red/near-infrared (NIR) fluorescence (photoluminescence quantum yield (PLQY) = 0.84 in toluene) even at room temperature and in the solid state (PLQY = 0.19). TTH displays a large Stokes shift (307 nm in benzonitrile) and solvatochromic behavior, which is unusual for a centrosymmetric, nonpolar, and low-conjugated species. These outstanding emission features are interpreted through quantum-chemical calculations, indicating that its fluorescence arises from the low-lying dark doubly excited zwitterionic state, typically found at low excitation energies in diradicaloids, acquiring dipole moment and intensity by state mixing via twisting around the strongly elongated exocyclic CC bonds of the excited p-quinodimethane (pQDM) core, with a mechanism similar to sudden polarization occurring in olefins. Such a mechanism is derived from ns and fs transient absorption measurements.
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Affiliation(s)
- Angela Punzi
- Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy
| | - Yasi Dai
- Dipartimento di Chimica "Giacomo Ciamician", Università di Bologna and INSTM UdR Bologna, Via F. Selmi 2, 40126 Bologna, Italy
| | - Carlo N Dibenedetto
- Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy
- CNR-Istituto per i Processi Chimico Fisici (CNR-IPCF), SS Bari, Via E. Orabona 4, 70125 Bari, Italy
| | - Ernesto Mesto
- Dipartimento di Scienze della Terra e Geoambientali, Università degli Studi di Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy
| | - Emanuela Schingaro
- Dipartimento di Scienze della Terra e Geoambientali, Università degli Studi di Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy
| | - Tobias Ullrich
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Marinella Striccoli
- CNR-Istituto per i Processi Chimico Fisici (CNR-IPCF), SS Bari, Via E. Orabona 4, 70125 Bari, Italy
| | - Dirk M Guldi
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Fabrizia Negri
- Dipartimento di Chimica "Giacomo Ciamician", Università di Bologna and INSTM UdR Bologna, Via F. Selmi 2, 40126 Bologna, Italy
| | - Gianluca M Farinola
- Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy
| | - Davide Blasi
- Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy
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6
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Gorgon S, Lv K, Grüne J, Drummond BH, Myers WK, Londi G, Ricci G, Valverde D, Tonnelé C, Murto P, Romanov AS, Casanova D, Dyakonov V, Sperlich A, Beljonne D, Olivier Y, Li F, Friend RH, Evans EW. Reversible spin-optical interface in luminescent organic radicals. Nature 2023; 620:538-544. [PMID: 37587296 PMCID: PMC10432275 DOI: 10.1038/s41586-023-06222-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 05/16/2023] [Indexed: 08/18/2023]
Abstract
Molecules present a versatile platform for quantum information science1,2 and are candidates for sensing and computation applications3,4. Robust spin-optical interfaces are key to harnessing the quantum resources of materials5. To date, carbon-based candidates have been non-luminescent6,7, which prevents optical readout via emission. Here we report organic molecules showing both efficient luminescence and near-unity generation yield of excited states with spin multiplicity S > 1. This was achieved by designing an energy resonance between emissive doublet and triplet levels, here on covalently coupled tris(2,4,6-trichlorophenyl) methyl-carbazole radicals and anthracene. We observed that the doublet photoexcitation delocalized onto the linked acene within a few picoseconds and subsequently evolved to a pure high-spin state (quartet for monoradical, quintet for biradical) of mixed radical-triplet character near 1.8 eV. These high-spin states are coherently addressable with microwaves even at 295 K, with optical readout enabled by reverse intersystem crossing to emissive states. Furthermore, for the biradical, on return to the ground state the previously uncorrelated radical spins either side of the anthracene shows strong spin correlation. Our approach simultaneously supports a high efficiency of initialization, spin manipulations and light-based readout at room temperature. The integration of luminescence and high-spin states creates an organic materials platform for emerging quantum technologies.
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Affiliation(s)
- Sebastian Gorgon
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
- Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, UK.
| | - Kuo Lv
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, P. R. China
| | - Jeannine Grüne
- Experimental Physics VI, Faculty of Physics and Astronomy, University of Würzburg, Würzburg, Germany
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | | | - William K Myers
- Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, UK
| | - Giacomo Londi
- Laboratory for Computational Modelling of Functional Materials, Namur Institute of Structured Matter, University of Namur, Namur, Belgium
| | - Gaetano Ricci
- Laboratory for Computational Modelling of Functional Materials, Namur Institute of Structured Matter, University of Namur, Namur, Belgium
| | - Danillo Valverde
- Laboratory for Computational Modelling of Functional Materials, Namur Institute of Structured Matter, University of Namur, Namur, Belgium
| | | | - Petri Murto
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | | | | | - Vladimir Dyakonov
- Experimental Physics VI, Faculty of Physics and Astronomy, University of Würzburg, Würzburg, Germany
| | - Andreas Sperlich
- Experimental Physics VI, Faculty of Physics and Astronomy, University of Würzburg, Würzburg, Germany
| | - David Beljonne
- Laboratory for Chemistry of Novel Materials, University of Mons, Mons, Belgium
| | - Yoann Olivier
- Laboratory for Computational Modelling of Functional Materials, Namur Institute of Structured Matter, University of Namur, Namur, Belgium
| | - Feng Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, P. R. China
| | | | - Emrys W Evans
- Department of Chemistry, Swansea University, Swansea, UK.
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7
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Gao S, Cui Z, Li F. Doublet-emissive materials for organic light-emitting diodes: exciton formation and emission processes. Chem Soc Rev 2023; 52:2875-2885. [PMID: 37052349 DOI: 10.1039/d2cs00772j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Doublet-emission is mainly discovered in stable radicals, lanthanide-metal complexes with an f1 electron configuration and transition-metal complexes with a low-spin d5 electron configuration, and has a distinct radiation mechanism from closed-shell luminescent molecules and thus technology opportunities. There exists an unpaired electron in the frontier molecular orbitals which enables efficient nanosecond-scale luminescence in these materials due to the spin-allowed transitions between doublet-spin states. In this review, we summarize recent advances in these materials and their application in organic light emitting diodes (OLEDs). The photoluminescence and electroluminescence mechanisms of different doublet-emissive molecular systems are discussed, in addition to the photophysical phenomena arising from doublet states. We also outline the current challenges faced by each molecular system, and the potential outlook on the future research trends in this field.
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Affiliation(s)
- Shengxiang Gao
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.
| | - Zhiyuan Cui
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.
| | - Feng Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.
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8
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Li X, Wang YL, Chen C, Han YF. Luminescent Crystalline Carbon- and Nitrogen-Centered Organic Radicals Based on N-Heterocyclic Carbene-Triphenylamine Hybrids. Chemistry 2023; 29:e202203242. [PMID: 36331436 DOI: 10.1002/chem.202203242] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/02/2022] [Accepted: 11/04/2022] [Indexed: 11/06/2022]
Abstract
Developing luminescent radicals with tunable emission is a challenging task due to the limitation of alternative skeletons. Herein, a series of carbene-triphenylamine hybrids were prepared by the direct C2-arylation of N-heterocyclic carbenes with 4-bromo-N,N-bis(4-methoxyphenyl)aniline. These hybrids showed multiple redox-active properties and could be converted to carbon-centered luminescent radicals with blue-to-cyan emissions (λmax : 436-486 nm) or nitrogen-centered luminescent radicals with orange emissions (λmax : 590-623 nm) through chemical reduction or oxidation, respectively. The radical species were characterized by electron paramagnetic resonance spectroscopy, ultraviolet-visible spectroscopy, and single-crystal X-ray diffractometry analysis. Notably, the corresponding nitrogen-centered radicals exhibited good stability in atmospheric air, and their thermal decomposition temperatures were determined to be above 200 °C. In addition, spectral and theoretical calculations indicate that all radicals exhibit anti-Kasha emissions.
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Affiliation(s)
- Xin Li
- Key Laboratory of Synthetic and, Natural Functional Molecule of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China
| | - Yi-Lin Wang
- Key Laboratory of Synthetic and, Natural Functional Molecule of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China
| | - Can Chen
- Key Laboratory of Synthetic and, Natural Functional Molecule of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China
| | - Ying-Feng Han
- Key Laboratory of Synthetic and, Natural Functional Molecule of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China
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9
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Hattori Y, Kitajima R, Ota W, Matsuoka R, Kusamoto T, Sato T, Uchida K. The simplest structure of a stable radical showing high fluorescence efficiency in solution: benzene donors with triarylmethyl radicals. Chem Sci 2022; 13:13418-13425. [PMID: 36507177 PMCID: PMC9682904 DOI: 10.1039/d2sc05079j] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 10/24/2022] [Indexed: 12/15/2022] Open
Abstract
Donor-radical acceptor systems have recently attracted much attention as efficient doublet emitters that offer significant advantages for applications such as OLEDs. We employed an alkylbenzene (mesityl group) as the simplest donor to date and added it to a diphenylpyridylmethyl radical acceptor. The (3,5-difluoro-4-pyridyl)bis[2,6-dichloro-4-(2,4,6-trimethylphenyl)phenyl]methyl radical (Mes2F2PyBTM) was prepared in only three steps from commercially available reagents. A stable radical composed of only one pyridine ring, four benzene rings, methyl groups, halogens, and hydrogens showed fluorescence of over 60% photoluminescence quantum yield (PLQY) in chloroform, dichloromethane, and PMMA. The key to high fluorescence efficiency was benzene rings perpendicular to the diphenylpyridylmethyl radical in the doublet ground (D0) state. The relatively low energy of the β-HOMO and the electron-accepting character of the radical enabled the use of benzenes as electron donors. Furthermore, the structural relaxation of the doublet lowest excited (D1) state was minimized by steric hindrance of the methyl groups. The reasons for this high efficiency include the relatively fast fluorescence transition and the slow internal conversion, both of which were explained by the overlap density between the D1 and D0 states.
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Affiliation(s)
- Yohei Hattori
- Materials Chemistry Course, Faculty of Advanced Science and Technology, Ryukoku UniversitySetaOtsuShiga 520-2194Japan
| | - Ryota Kitajima
- Materials Chemistry Course, Faculty of Advanced Science and Technology, Ryukoku UniversitySetaOtsuShiga 520-2194Japan
| | - Wataru Ota
- MOLFEX, Inc.Takano-Nishibiraki-cho 34-4Kyoto 606-8103Japan
| | - Ryota Matsuoka
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science5-1, Higashiyama, MyodaijiOkazakiAichi 444-8787Japan,SOKENDAI (The Graduate University for Advanced Studies)Shonan VillageHayamaKanagawa 240-0193Japan
| | - Tetsuro Kusamoto
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science5-1, Higashiyama, MyodaijiOkazakiAichi 444-8787Japan,SOKENDAI (The Graduate University for Advanced Studies)Shonan VillageHayamaKanagawa 240-0193Japan,JST-PRESTO4-1-8, HonchoKawaguchiSaitama 332-0012Japan
| | - Tohru Sato
- Fukui Institute for Fundamental Chemistry, Kyoto UniversityTakano-Nishibiraki-cho 34-4Kyoto 606-8103Japan,Department of Molecular Engineering, Graduate School of Engineering, Kyoto UniversityNishikyo-kuKyoto 615-8510Japan
| | - Kingo Uchida
- Materials Chemistry Course, Faculty of Advanced Science and Technology, Ryukoku UniversitySetaOtsuShiga 520-2194Japan
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