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Ema F, Tanabe M, Saito S, Yoneda T, Sugisaki K, Tachikawa T, Akimoto S, Yamauchi S, Sato K, Osuka A, Takui T, Kobori Y. Charge-Transfer Character Drives Möbius Antiaromaticity in the Excited Triplet State of Twisted [28]Hexaphyrin. J Phys Chem Lett 2018; 9:2685-2690. [PMID: 29739190 DOI: 10.1021/acs.jpclett.8b00740] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Möbius aromatic molecules have attracted great attention as new functional materials because of their π-orbital cyclic conjugations lying along the twisted Möbius topology. To elucidate the electronic character of the lowest excited triplet (T1) state of a Möbius aromatic [28]hexaphyrin, we employed a time-resolved electron paramagnetic resonance (TREPR) method with applied magnetophotoselection measurements at 77 K. Analyses of the EPR parameters have revealed that the T1 state possesses intramolecular charge-transfer (CT) character together with local excitation character residing at one side in the Möbius strip ring. We have also demonstrated that the CT character between orthogonal unpaired orbitals triggers quick triplet deactivation by spin-orbit coupling. This deactivation can be an important barometer to represent the "antiaromaticity" because of a connection between the orthogonal CT character and instability by a weakened spin-spin exchange coupling in the T1 state.
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Affiliation(s)
- Fumitoshi Ema
- Department of Chemistry , Graduate School of Science, Kobe University , 1-1 Rokkodai-cho , Nada-ku, Kobe 657-8501 , Japan
| | - Mana Tanabe
- Institute of Multidisciplinary Research for Advanced Materials , Tohoku University , Katahira 2-1-1 , Aoba-ku, Sendai 980-8577 , Japan
| | - Shohei Saito
- Department of Chemistry , Graduate School of Science, Kyoto University , Sakyo-ku, Kyoto 606-8502 , Japan
| | - Tomoki Yoneda
- Department of Chemistry , Graduate School of Science, Kyoto University , Sakyo-ku, Kyoto 606-8502 , Japan
| | - Kenji Sugisaki
- Department of Chemistry and Molecular Materials Science , Graduate School of Science, Osaka City University , 3-3-138 Sugimoto , Sumiyoshi-ku, Osaka 558-8585 , Japan
| | - Takashi Tachikawa
- Department of Chemistry , Graduate School of Science, Kobe University , 1-1 Rokkodai-cho , Nada-ku, Kobe 657-8501 , Japan
- Molecular Photoscience Research Center , Kobe University , 1-1 Rokkodai-cho , Nada-ku, Kobe 657-8501 , Japan
| | - Seiji Akimoto
- Department of Chemistry , Graduate School of Science, Kobe University , 1-1 Rokkodai-cho , Nada-ku, Kobe 657-8501 , Japan
| | - Seigo Yamauchi
- Institute of Multidisciplinary Research for Advanced Materials , Tohoku University , Katahira 2-1-1 , Aoba-ku, Sendai 980-8577 , Japan
| | - Kazunobu Sato
- Department of Chemistry and Molecular Materials Science , Graduate School of Science, Osaka City University , 3-3-138 Sugimoto , Sumiyoshi-ku, Osaka 558-8585 , Japan
| | - Atsuhiro Osuka
- Department of Chemistry , Graduate School of Science, Kyoto University , Sakyo-ku, Kyoto 606-8502 , Japan
| | - Takeji Takui
- Department of Chemistry and Molecular Materials Science , Graduate School of Science, Osaka City University , 3-3-138 Sugimoto , Sumiyoshi-ku, Osaka 558-8585 , Japan
| | - Yasuhiro Kobori
- Department of Chemistry , Graduate School of Science, Kobe University , 1-1 Rokkodai-cho , Nada-ku, Kobe 657-8501 , Japan
- Molecular Photoscience Research Center , Kobe University , 1-1 Rokkodai-cho , Nada-ku, Kobe 657-8501 , Japan
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Klenina IB, Makhneva ZK, Moskalenko AA, Kuzmin AN, Proskuryakov II. Singlet-triplet excitation fission in light-harvesting complexes of photosynthetic bacteria and in isolated carotenoids. Biophysics (Nagoya-shi) 2013. [DOI: 10.1134/s0006350913010077] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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