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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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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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Zhou HP, Wu SX, Duan YC, Gao FW, Pan QQ, Kan YH, Su ZM. The combination of skeleton-engineering and periphery-engineering: a design strategy for organic doublet emitters. Phys Chem Chem Phys 2022; 24:26853-26862. [DOI: 10.1039/d2cp03948f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A series of radicals based on tris(2,4,6-trichlorophenyl)methyl (TTM) were theoretically designed and evaluated by combining skeleton-engineering and periphery-engineering strategies.
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Affiliation(s)
- Hai-Ping Zhou
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, Changchun 130012, China
| | - Shui-Xing Wu
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province, School of Chemistry & Chemical Engineering, Hainan Normal University, Haikou 571158, China
| | - Ying-Chen Duan
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, Changchun 130012, China
| | - Feng-Wei Gao
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, Changchun 130012, China
| | - Qing-Qing Pan
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, Changchun 130012, China
| | - Yu-He Kan
- Jiangsu Province Key Laboratory for Chemistry of Low-Dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai’an 223300, China
| | - Zhong-Min Su
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, Changchun 130012, China
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
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