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Queiroz M, Alves TV, Rivelino R, Canuto S. Influence of Solvents and Halogenation on ESIPT of Benzimidazole Derivatives for Designing Turn-on Fluorescence Probes. ACS OMEGA 2024; 9:22102-22111. [PMID: 38799309 PMCID: PMC11112562 DOI: 10.1021/acsomega.4c00488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 05/29/2024]
Abstract
This work reports a theoretical investigation of the solvent polarity as well as the halogenation of benzimidazole derivatives during excited state intramolecular proton transfer (ESIPT). It details how the environment and halogen substitution may contribute to the efficiency of ESIPT upon keto-enol tautomerism and exploits this effect to design fluorescence sensing. For this purpose, we first examine the conformational equilibrium of benzimidazole derivatives containing different halogen atoms, which results in intramolecular proton transfer, using density-functional theory (DFT) combined with the polarizable continuum model (PCM). Then we evaluate the fluorescence of the benzimidazole derivatives in different dielectric constants within time-dependent DFT (TD-DFT) approaches. Our results quantitatively allow the determination of large Stokes shifts in nonpolar solvents around 100 nm. These theoretical results are in agreement with experimental solvatochromism studies of benzimidazoles. The effect of halogenation, with fluorine, chlorine, and bromine, is less important than solvent polarization when ESIPT takes place. Thus, halogenation can be properly chosen depending on the interest of the synthesis of benzimidazole-based turn-on fluorescence in appropriate solvents.
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Affiliation(s)
- Murillo
H. Queiroz
- Departamento
de Físico-Química, Instituto
de Química, Universidade Federal da Bahia, Rua Barão de Jeremoabo, 147, Salvador, Bahia 40170-115, Brazil
| | - Tiago V. Alves
- Departamento
de Físico-Química, Instituto
de Química, Universidade Federal da Bahia, Rua Barão de Jeremoabo, 147, Salvador, Bahia 40170-115, Brazil
| | - Roberto Rivelino
- Instituto
de Física, Universidade Federal da
Bahia, Salvador, Bahia 40210-340, Brazil
| | - Sylvio Canuto
- Instituto
de Física, Universidade de São
Paulo, CP 66318, São Paulo, São Paulo 05315-970, Brazil
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Shekhovtsov NA, Nikolaenkova EB, Ryadun AA, Samsonenko DG, Tikhonov AY, Bushuev MB. ESIPT-Capable 4-(2-Hydroxyphenyl)-2-(Pyridin-2-yl)-1 H-Imidazoles with Single and Double Proton Transfer: Synthesis, Selective Reduction of the Imidazolic OH Group and Luminescence. Molecules 2023; 28:molecules28041793. [PMID: 36838780 PMCID: PMC9962989 DOI: 10.3390/molecules28041793] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 02/07/2023] [Accepted: 02/09/2023] [Indexed: 02/16/2023] Open
Abstract
1H-Imidazole derivatives establish one of the iconic classes of ESIPT-capable compounds (ESIPT = excited state intramolecular proton transfer). This work presents the synthesis of 1-hydroxy-4-(2-hydroxyphenyl)-5-methyl-2-(pyridin-2-yl)-1H-imidazole (LOH,OH) as the first example of ESIPT-capable imidazole derivatives wherein the imidazole moiety simultaneously acts as a proton acceptor and a proton donor. The reaction of LOH,OH with chloroacetone leads to the selective reduction of the imidazolic OH group (whereas the phenolic OH group remains unaffected) and to the isolation of 4-(2-hydroxyphenyl)-5-methyl-2-(pyridin-2-yl)-1H-imidazole (LH,OH), a monohydroxy congener of LOH,OH. Both LOH,OH and LH,OH demonstrate luminescence in the solid state. The number of OH···N proton transfer sites in these compounds (one for LH,OH and two for LOH,OH) strongly affects the luminescence mechanism and color of the emission: LH,OH emits in the light green region, whereas LOH,OH luminesces in the orange region. According to joint experimental and theoretical studies, the main emission pathway of both compounds is associated with T1 → S0 phosphorescence and not related to ESIPT. At the same time, LOH,OH also exhibits S1 → S0 fluorescence associated with ESIPT with one proton transferred from the hydroxyimidazole moiety to the pyridine moiety, which is not possible for LH,OH due to the absence of the hydroxy group in the imidazole moiety.
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Affiliation(s)
- Nikita A. Shekhovtsov
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia
- Correspondence: (N.A.S.); (A.Y.T.); (M.B.B.)
| | - Elena B. Nikolaenkova
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, 9, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia
| | - Alexey A. Ryadun
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia
| | - Denis G. Samsonenko
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia
| | - Alexsei Ya. Tikhonov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, 9, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia
- Correspondence: (N.A.S.); (A.Y.T.); (M.B.B.)
| | - Mark B. Bushuev
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia
- Correspondence: (N.A.S.); (A.Y.T.); (M.B.B.)
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Hassan AU, Sumrra SH, Nkungli NK, Güleryüz C. Theoretical probing of 3d nano metallic clusters as next generation non-linear optical materials. RESULTS IN CHEMISTRY 2022. [DOI: 10.1016/j.rechem.2022.100627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Shekhovtsov NA, Nikolaenkova EB, Berezin AS, Plyusnin VF, Vinogradova KA, Naumov DY, Pervukhina NV, Tikhonov AY, Bushuev MB. Tuning ESIPT-coupled luminescence by expanding π-conjugation of a proton acceptor moiety in ESIPT-capable zinc(II) complexes with 1-hydroxy-1 H-imidazole-based ligands. Dalton Trans 2022; 51:15166-15188. [PMID: 36129344 DOI: 10.1039/d2dt02460h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The emission of ESIPT-fluorophores is known to be sensitive to various external and internal stimuli and can be fine-tuned through substitution in the proton-donating and proton-accepting groups. The incorporation of metal ions in the molecules of ESIPT fluorophores without their deprotonation is an emerging area of research in coordination chemistry which provides chemists with a new factor affecting the ESIPT reaction and ESIPT-coupled luminescence. In this paper we present 1-hydroxy-5-methyl-4-(pyridin-2-yl)-2-(quinolin-2-yl)-1H-imidazole (HLq) as a new ESIPT-capable ligand. Due to the spatial separation of metal binding and ESIPT sites this ligand can coordinate metal ions without being deprotonated. The reactions of ZnHal2 with HLq afford ESIPT-capable [Zn(HLq)Hal2] (Hal = Cl, Br, I) complexes. In the solid state HLq and [Zn(HLq)Hal2] luminesce in the orange region (λmax = 600-650 nm). The coordination of HLq by Zn2+ ions leads to the increase in the photoluminescence quantum yield due to the chelation-enhanced fluorescence effect. The ESIPT process is barrierless in the S1 state, leading to the only possible fluorescence channel in the tautomeric form (T), S1T → S0T. The emission of [Zn(HLq)Hal2] in the solid state is blue-shifted as compared with HLq due to the stabilization of the ground state and destabilization of the excited state. In CH2Cl2 solutions, the compounds demonstrate dual emission in the UV (λmax = 358 nm) and green (λmax = 530 nm) regions. This dual emission is associated with two radiative deactivation channels in the normal (N) and tautomeric (T) forms, S1N → S0N and S1T → S0T, originating from two minima on the excited state potential energy surfaces. High energy barriers for the GSIPT process allow the trapping of molecules in the minimum of the tautomeric form, S0T, resulting in the possibility of the S0T → S1T photoexcitation and extraordinarily small Stokes shifts in the solid state. Finally, the π-system of quinolin-2-yl group facilitates the delocalization of the positive charge in the proton-accepting part of the molecule and promotes the ESIPT reaction.
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Affiliation(s)
- Nikita A Shekhovtsov
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia.
| | - Elena B Nikolaenkova
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 9, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia
| | - Alexey S Berezin
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia.
| | - Victor F Plyusnin
- Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences, 3, Institutskaya str., Novosibirsk, 630090, Russia
| | - Katerina A Vinogradova
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia.
| | - Dmitry Yu Naumov
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia.
| | - Natalia V Pervukhina
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia.
| | - Alexsei Ya Tikhonov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 9, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia
| | - Mark B Bushuev
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia.
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Shi L, Yang D. The alkoxylation effects on the excited‐state intramolecular proton transfer behaviors for 2,6‐bis(benzothiazolyl‐2‐yl)phenol fluorophore: A theoretical research. J PHYS ORG CHEM 2022. [DOI: 10.1002/poc.4341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Lijuan Shi
- Division of General Education Zhongyuan Institute of Science and Technology Zhengzhou China
| | - Dapeng Yang
- College of Physics and Electronics North China University of Water Resources and Electric Power Zhengzhou China
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