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Fedotova TV, Zakharova GV, Gutrov VN, Markelov VP, Svyatoslavskaya TA, Svyatoslavskii NL, Chibisov AK, Sazonov SK, Gromov SP. A Study of Photoprocesses of 3,3'-Diethyl-5,5'-Dichlorothiacarbocyanine in Water and Methanol. HIGH ENERGY CHEMISTRY 2020. [DOI: 10.1134/s0018143920030042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Fedotova TV, Zakharova GV, Gutrov VN, Chibisov AK. Photoinduced Electron Transfer in the System Eosin–Europium–Cucurbit[6–8]urils in Water. HIGH ENERGY CHEMISTRY 2020. [DOI: 10.1134/s0018143919060055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Zakharova GV, Fedotova TV, Gutrov VN, Chibisov AK, Alfimov MV. Triplet Energy Transfer from Polymethine Dimers in the Complexes with Cucurbit[8]urils. HIGH ENERGY CHEMISTRY 2020. [DOI: 10.1134/s0018143919060158 10.1134/s0018143919060158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Zakharova GV, Fedotova TV, Gutrov VN, Chibisov AK, Alfimov MV. Triplet Energy Transfer from Polymethine Dimers in the Complexes with Cucurbit[8]urils. HIGH ENERGY CHEMISTRY 2020. [DOI: 10.1134/s0018143919060158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Yin H, Cheng Q, Rosas R, Viel S, Monnier V, Charles L, Siri D, Gigmes D, Ouari O, Wang R, Kermagoret A, Bardelang D. A Cucurbit[8]uril 2:2 Complex with a Negative pK a Shift. Chemistry 2019; 25:12552-12559. [PMID: 31286592 DOI: 10.1002/chem.201902057] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/13/2019] [Indexed: 12/22/2022]
Abstract
A viologen derivative carrying a benzimidazole group (V-P-I 2+ ; viologen-phenylene-imidazole V-P-I) can be dimerized in water using cucurbit[8]uril (CB[8]) in the form of a 2:2 complex resulting in a negative shift of the guest pKa , by more than 1 pH unit, contrasting with the positive pKa shift usually observed for CB-based complexes. Whereas 2:2 complex protonation is unclear by NMR, silver cations have been used for probing the accessibility of the imidazole groups of the 2:2 complexes. The protonation capacity of the buried imidazole groups is reduced, suggesting that CB[8] could trigger proton release upon 2:2 complex formation. The addition of CB[8] to a solution containing V-P- I3+ indeed released protons as monitored by pH-metry and visualized by a coloured indicator. This property was used to induce a host/guest swapping, accompanied by a proton transfer, between V-P-I 3+ ⋅CB[7] and a CB[8] complex of 1-methyl-4-(4-pyridyl)pyridinium. The origin of this negative pKa shift is proposed to stand in an ideal charge state, and in the position of the two pH-responsive fragments inside the two CB[8] which, alike residues engulfed in proteins, favour the deprotonated form of the guest molecules. Such proton release triggered by a recognition event is reminiscent of several biological processes and may open new avenues toward bioinspired enzyme mimics catalyzing proton transfer or chemical reactions.
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Affiliation(s)
- Hang Yin
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Avenida da Universidade, Taipa, Macau, P. R. China
| | - Qian Cheng
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Avenida da Universidade, Taipa, Macau, P. R. China
| | - Roselyne Rosas
- Aix Marseille Univ, CNRS, Spectropole, FR 1739, Marseille, France
| | - Stéphane Viel
- Aix Marseille Univ, CNRS, ICR, Marseille, France.,Institut Universitaire de France, Paris, France
| | - Valérie Monnier
- Aix Marseille Univ, CNRS, Spectropole, FR 1739, Marseille, France
| | | | - Didier Siri
- Aix Marseille Univ, CNRS, ICR, Marseille, France
| | | | | | - Ruibing Wang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Avenida da Universidade, Taipa, Macau, P. R. China
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