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Nomura S, Fujii K, Sugihara H, Endo T, Kimura Y. Anion Effect on the Excited-State Intramolecular Proton Transfer of 4'- N, N-Diethylamino-3-hydroxyflavone in Ionic Liquids. J Phys Chem B 2024; 128:6549-6559. [PMID: 38935614 DOI: 10.1021/acs.jpcb.4c02573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
The excited-state intramolecular proton transfer (ESIPT) reaction of 4'-N,N,-diethylamino-3-hydroxyflavone (C2HF) was studied using time-resolved fluorescence measurements in ionic liquids (ILs) of various anions with a fixed cation (1-ethyl-3-methylimidazolium [C2mim]+). C2HF showed an ESIPT reaction from the normal excited state (N*; keto form) to the tautomer excited state (T*; enol form) where both states are emissive. The ESIPT rate and yield were obtained by analyzing the time-resolved fluorescence spectra measured using the optical Kerr gate method. Both the ESIPT rate and yield decreased with increasing hydrogen-bond accepting ability of the anion. According to density functional theory calculations, the complex formation energy between C2HF and the anion became significantly negative with increasing the hydrogen-bond accepting ability of anion. The pseudoequilibrium constant between N* and T* ([T*]/[N*]) in the electronic excited state decreased with increasing hydrogen-bond accepting ability of the anion, while it increased with increasing the alkyl-chain length of alkyl sulfonate. The excitation wavelength dependence of the ESIPT rate and yield was studied for C2HF in [C2mim][C6H13SO3]. The ESIPT yield decreased by nearly a factor of 2 with increasing excitation wavelength from 360 to 425 nm, although the change in the ESIPT rate was small. The solvation heterogeneity due to the alkyl chain in the anion was considered to be the reason for the excitation wavelength dependence.
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Affiliation(s)
- Shohnosuke Nomura
- Department of Applied Chemistry, Graduate School of Science and Engineering, Doshisha University, 2-1, Tatara Miyakodani, Kyotanabe-City, Kyoto 610-0321, Japan
| | - Kaori Fujii
- National Institute of Advanced Industrial Science and Technology, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Hiroaki Sugihara
- Division of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, 2-1, Tatara Miyakodani, Kyotanabe-City, Kyoto 610-0321, Japan
| | - Takatsugu Endo
- Division of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, 2-1, Tatara Miyakodani, Kyotanabe-City, Kyoto 610-0321, Japan
| | - Yoshifumi Kimura
- Department of Applied Chemistry, Graduate School of Science and Engineering, Doshisha University, 2-1, Tatara Miyakodani, Kyotanabe-City, Kyoto 610-0321, Japan
- Division of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, 2-1, Tatara Miyakodani, Kyotanabe-City, Kyoto 610-0321, Japan
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Fujii K, Kimura Y. Solvent Role of Ionic Liquids in Fundamental Chemical Reaction Dynamics Analyzed by Time-Resolved Spectroscopy. CHEM REC 2023; 23:e202200242. [PMID: 36634996 DOI: 10.1002/tcr.202200242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/24/2022] [Indexed: 01/14/2023]
Abstract
Ionic liquids (ILs), which are used as solvents for chemical reactions, are different from conventional organic solvents owing to their designability. Physicochemical parameters of the ILs, such as polarity and viscosity, that affect chemical equilibria and reaction kinetics can be tuned by changing the combination of anions and cations or by varying the lengths of the alkyl chains present in the cations. We were interested in knowing how these physicochemical parameters affect fundamental chemical reactions in ILs. Therefore, in this personal account, we investigate our recent work on two different photochemical reactions in ILs, namely excited-state intramolecular proton transfer of hydroxyflavone and photodissociation of aminodisulfide, using time-resolved spectroscopic techniques. Interestingly, the roles of the ILs in these chemical reactions are quite different. The effect of the cationic species of the ILs (i. e., the head groups and number of alkyl carbons) on the solvation environment upon photoexcitation and reaction rate are discussed.
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Affiliation(s)
- Kaori Fujii
- Faculty of Science and Engineering, Doshisha University, Kyotanabe-city, Kyoto 610-0321, Japan
| | - Yoshifumi Kimura
- Graduate School of Science and Engineering, Faculty of Science and Engineering, Doshisha University, Kyotanabe-city, Kyoto 610-0321, Japan
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Gu H, Wang W, Wu W, Wang M, Liu Y, Jiao Y, Wang F, Wang F, Chen X. Excited-state intramolecular proton transfer (ESIPT)-based fluorescent probes for biomarker detection: design, mechanism, and application. Chem Commun (Camb) 2023; 59:2056-2071. [PMID: 36723346 DOI: 10.1039/d2cc06556h] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Biomarkers are essential in biology, physiology, and pharmacology; thus, their detection is of extensive importance. Fluorescent probes provide effective tools for detecting biomarkers exactly. Excited state intramolecular proton transfer (ESIPT), one of the significant photophysical processes that possesses specific photoisomerization between Keto and Enol forms, can effectively avoid annoying interference from the background with a large Stokes shift. Hence, ESIPT is an excellent choice for biomarker monitoring. Based on the ESIPT process, abundant probes were designed and synthesized using three major design methods. In this review, we conclude probes for 14 kinds of biomarkers based on ESIPT explored in the past five years, summarize these general design methods, and highlight their application for biomarker detection in vitro or in vivo.
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Affiliation(s)
- Hao Gu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, China.
| | - Wenjing Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, China.
| | - Wenyan Wu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, China.
| | - Maolin Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, China.
| | - Yongrong Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, China.
| | - Yanjun Jiao
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, China.
| | - Fan Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, China.
| | - Fang Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, China.
| | - Xiaoqiang Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, China.
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Nakajima S, Sumida H, Endo T, Kimura Y. Study on the Translational Diffusion of Transient Species in 1-Alkyl-3-methylimidazolium-Based Ionic Liquids by Transient Grating Spectroscopy. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2022. [DOI: 10.1246/bcsj.20220099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Satoshi Nakajima
- Department of Applied Chemistry, Graduate School of Science and Engineering, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe, Kyoto 610-0321, Japan
| | - Hiroki Sumida
- Department of Applied Chemistry, Graduate School of Science and Engineering, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe, Kyoto 610-0321, Japan
| | - Takatsugu Endo
- Division of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe, Kyoto 610-0321, Japan
| | - Yoshifumi Kimura
- Department of Applied Chemistry, Graduate School of Science and Engineering, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe, Kyoto 610-0321, Japan
- Division of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe, Kyoto 610-0321, Japan
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