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Mizuno A, Matsuoka R, Kimura S, Ochiai K, Kusamoto T. Spin-Correlated Luminescence of a Carbazole-Containing Diradical Emitter: Single-Molecule Magnetoluminescence and Thermally Activated Emission. J Am Chem Soc 2024; 146:18470-18483. [PMID: 38921686 DOI: 10.1021/jacs.4c03972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
Luminescent radicals have been intensively studied as a new class of materials exhibiting novel photofunctions unique to open-shell systems. When luminescent radicals are assembled, intriguing spin-correlated luminescence phenomena emerge, including excimer-like emission and magnetic-field effects on luminescence (i.e., magnetoluminescence, MagLum). However, the underlying mechanisms of these phenomena arising from spin multiplicity and spin-dependent excited-state dynamics are poorly understood due to the limited number of luminescent polyradical systems available for study. In particular, the correlation between stronger intramolecular exchange interactions (|2J/kB| > ∼10 K, where J and kB are the intramolecular exchange coupling constant and the Boltzmann constant, respectively) and luminescence properties has not been fully explained. In this study, a novel carbazole-containing diradical emitter (1) and the corresponding monoradical (2) were prepared for the in-depth study of spin-correlated luminescence properties, with luminescence measurements under magnetic fields of up to 18 T. Diradical 1 has a negative 2J/kB value of several tens of kelvin and exhibits a single-molecule MagLum and thermally activated luminescence, whereas 2 does not. Detailed quantitative analyses revealed that both the spin-correlated luminescence properties of 1 are strongly dominated by ground-state spin statistics based on the Boltzmann distribution (i.e., 2J/kB values). Furthermore, diradical 1 exhibits external heavy-atom effects in heavy-atom-containing solvents such as iodobenzene, whereas monoradical 2 does not. This is the first experimental verification of external heavy-atom effects in polyradical emitters. This work demonstrates that polyradical emitters can be designed based on spin degrees of freedom in both ground and excited states.
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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
- Division of Chemistry, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Ryota Matsuoka
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- Division of Chemistry, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan
| | - Shojiro Kimura
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Keisuke Ochiai
- SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan
| | - Tetsuro Kusamoto
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- Division of Chemistry, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan
- JST-PRESTO, 4-1-8, Honcho, Kawaguchi, Saitama 332-0012, Japan
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Pascal S, David S, Andraud C, Maury O. Near-infrared dyes for two-photon absorption in the short-wavelength infrared: strategies towards optical power limiting. Chem Soc Rev 2021; 50:6613-6658. [DOI: 10.1039/d0cs01221a] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The recent advances in the field of two-photon absorbing chromophores in the short-wavelength infrared spectral range (SWIR 1100–2500 nm) are summarized, highlighting the development of optical power limiting devices in this spectral range.
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Affiliation(s)
- Simon Pascal
- Univ. Lyon
- ENS Lyon
- CNRS UMR 5182
- Laboratoire de Chimie
- 69364 Lyon
| | - Sylvain David
- Univ. Lyon
- ENS Lyon
- CNRS UMR 5182
- Laboratoire de Chimie
- 69364 Lyon
| | - Chantal Andraud
- Univ. Lyon
- ENS Lyon
- CNRS UMR 5182
- Laboratoire de Chimie
- 69364 Lyon
| | - Olivier Maury
- Univ. Lyon
- ENS Lyon
- CNRS UMR 5182
- Laboratoire de Chimie
- 69364 Lyon
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Rausch R, Röhr MIS, Schmidt D, Krummenacher I, Braunschweig H, Würthner F. Tuning phenoxyl-substituted diketopyrrolopyrroles from quinoidal to biradical ground states through (hetero-)aromatic linkers. Chem Sci 2020; 12:793-802. [PMID: 34163813 PMCID: PMC8179021 DOI: 10.1039/d0sc05475e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Strongly fluorescent halochromic 2,6-di-tert-butyl-phenol-functionalised phenyl-, thienyl- and furyl-substituted diketopyrrolopyrrole (DPP) dyes were deprotonated and oxidised to give either phenylene-linked DPP1˙˙ biradical (y 0 = 0.75) with a singlet open shell ground state and a thermally populated triplet state (ΔE ST = 19 meV; 1.8 kJ mol-1; 0.43 kcal mol-1) or thienylene/furylene-linked DPP2q and DPP3q compounds with closed shell quinoidal ground states. Accordingly, we identified the aromaticity of the conjugated (hetero-)aromatic bridge to be key for modulating the electronic character of these biradicaloid compounds and achieved a spin crossover from closed shell quinones DPP2q and DPP3q to open shell biradical DPP1˙˙ as confirmed by optical and magnetic spectroscopic studies (UV/vis/NIR, NMR, EPR) as well as computational investigations (spin-flip TD-DFT calculations in combination with CASSCF(4,4) and harmonic oscillator model of aromaticity (HOMA) analysis). Spectroelectrochemical studies and comproportionation experiments further prove the reversible formation of mixed-valent radical anions for the DPP2q and DPP3q quinoidal compounds with absorption bands edging into the NIR spectral region.
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Affiliation(s)
- Rodger Rausch
- Universität Würzburg, Institut für Organische Chemie Am Hubland 97074 Würzburg Germany
| | - Merle I S Röhr
- Universität Würzburg, Center for Nanosystems Chemistry (CNC) Theodor-Boveri-Weg 97074 Würzburg Germany
| | - David Schmidt
- Universität Würzburg, Institut für Organische Chemie Am Hubland 97074 Würzburg Germany .,Universität Würzburg, Center for Nanosystems Chemistry (CNC) Theodor-Boveri-Weg 97074 Würzburg Germany
| | - Ivo Krummenacher
- Universität Würzburg, Institut für Anorganische Chemie, Institute for Sustainable Chemistry and Catalysis with Boron Am Hubland 97074 Würzburg Germany
| | - Holger Braunschweig
- Universität Würzburg, Institut für Anorganische Chemie, Institute for Sustainable Chemistry and Catalysis with Boron Am Hubland 97074 Würzburg Germany
| | - Frank Würthner
- Universität Würzburg, Institut für Organische Chemie Am Hubland 97074 Würzburg Germany .,Universität Würzburg, Center for Nanosystems Chemistry (CNC) Theodor-Boveri-Weg 97074 Würzburg Germany
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