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Nobre DC, Delgado-Pinar E, Cunha C, Sérgio Seixas de Melo J. The role of the oxime group in the excited state deactivation processes of indirubin. Phys Chem Chem Phys 2024; 26:7416-7423. [PMID: 38351859 DOI: 10.1039/d3cp05260e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
The introduction of an oxime group into indirubin (INR) derivatives, including INROx, MINROx, and 6-BrINROx, and its impact on the spectral and photophysical properties of INR was investigated using a combination of fast-transient absorption (fs-TA/fs-UC) and steady-state fluorescence techniques. The oxime group introduces structural modifications that promote a rapid keto-enol tautomeric equilibrium and enhance the excited-state proton transfer (ESPT) process compared to its analogue, INR. In the oxime-indirubin derivatives investigated, the ESPT process is notably more efficient than what is observed in INR and indigo, occurring extremely fast (<1 ps) in all solvents, except for the viscous solvent glycerol. The more rapid deactivation mechanism precludes the formation of an intermediate species (syn-rotamer), as observed with INR. These findings are corroborated by time-dependent density functional theory (TDDFT) calculations. The work demonstrates that introducing an oxime group to INR, whether in nature or in the laboratory, results in an enhancement of its photostability.
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Affiliation(s)
- Danîela C Nobre
- University of Coimbra, CQC-ISM, Department of Chemistry, P3004-535 Coimbra, Portugal.
| | - Estefanía Delgado-Pinar
- University of Coimbra, CQC-ISM, Department of Chemistry, P3004-535 Coimbra, Portugal.
- Instituto de Ciencia Molecular, Departamento de Química Inorgánica, Universidad de Valencia, C/Catedrático José Beltrán 2, 46980, Paterna, Valencia, Spain
| | - Carla Cunha
- University of Coimbra, CQC-ISM, Department of Chemistry, P3004-535 Coimbra, Portugal.
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Shukla A, Jha VK, Chatterjee S. Non-trivial ground and excited state photophysics of a substituted phenol. Phys Chem Chem Phys 2024; 26:6655-6666. [PMID: 37975741 DOI: 10.1039/d3cp04570f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
5-(tert-Butyl)-2-hydroxy-1,3-isophthalaldehyde (5-tBHI) shows solvent dependent single or dual emission. The photophysics of 5-tBHI has been studied in a variety of solvents and the results were compared with that of the methyl derivative of the probe as well as the 5-tBHI anion. It has been found that the intramolecular H-bonded conformer of 5-tBHI predominantly exists in non-polar solvents, and undergoes facile excited state intramolecular proton transfer (ESIPT). On the other hand, a dynamic equilibrium can be found in polar, protic solvents, even in the ground state, except in water. NMR analyses confirm the loss of aromaticity of the probe in the ground state via anion formation, in equilibrium with the solvent mediated intermolecularly H-bonded state, in neat polar protic solvents like methanol. The proton transfer process, either intramolecularly or intermolecularly, was found to be of the order of 1 ps, and even faster than the instrumental resolution in the case of water. The current finding provides important insights on the photophysics of this small, substituted phenol.
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Affiliation(s)
- Aparna Shukla
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (Indian School of Mines) Dhanbad, Dhanbad 826004, Jharkhand, India.
| | - Vikas Kumar Jha
- Discipline of Chemistry, School of Chemical and Material Sciences, Department of Chemistry, Indian Institute of Technology Goa, Ponda, Goa 403401, India
| | - Soumit Chatterjee
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (Indian School of Mines) Dhanbad, Dhanbad 826004, Jharkhand, India.
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Delgado-Pinar E, Medeiros M, Costa T, Seixas de Melo JS. Highly Selective Fluorescent Sensors: Polyethylenimine Derivatives of Triphenylamine and Coumarin for GTP and ATP Interaction via Fluorescence Lifetime Imaging Microscopy. ACS APPLIED POLYMER MATERIALS 2023; 5:6176-6185. [PMID: 37588082 PMCID: PMC10426326 DOI: 10.1021/acsapm.3c00834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 06/28/2023] [Indexed: 08/18/2023]
Abstract
Chemical derivatives of polyethylenimine (PEI) receptors with either triphenylamine (TPA) or 7-hydroxy-4-methyl-coumarin (Cou) form stable complexes with adenine and guanine nucleotides in water. The host-guest complex modulation is found to be based on noncovalent molecular interactions such as π-π stacking and hydrogen bonding, which are dependent on the aromatic moieties attached to the polyaminic (PEI) backbone. PEI-TPA acts as a chemosensor with a recognition driving force based on aggregation-induced emission (AIE), involving π-π interaction between the nucleic base and TPA. It detects GTP by a chelation enhancement quenching effect of fluorescence (CHEQ) with a measured logarithm stability constant, log β = 7.7. By varying the chemical characteristics of the fluorophore, as in the PEI-Cou system, the driving force for recognition changes from a π-π interaction to an electrostatic interaction. The coumarin derivative detects ATP with a log β value one order of magnitude higher than that for GTP, allowing for the selective recognition of the two nucleotides in a 100% aqueous solution. Furthermore, fluorescence lifetime imaging microscopy (FLIM) allows for a correlation between the selectivity of PEI-TPA toward nucleotides and the morphology of the structures formed upon ATP and GTP recognition. This study offers valuable insights into the design of receptors for the selective recognition of nucleotides in water.
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Affiliation(s)
- Estefanía Delgado-Pinar
- CQC-IMS,
Department of Chemistry, University of Coimbra, Rua Larga, Coimbra 3004-535, Portugal
- Instituto
de Ciencia, Molecular, Departamento de Química Inorgánica, Universidad de Valencia, C/Catedrático José Beltrán
2, Paterna 46980, Spain
| | - Matilde Medeiros
- CQC-IMS,
Department of Chemistry, University of Coimbra, Rua Larga, Coimbra 3004-535, Portugal
| | - Telma Costa
- CQC-IMS,
Department of Chemistry, University of Coimbra, Rua Larga, Coimbra 3004-535, Portugal
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Verma P, Rosspeintner A, Dereka B, Vauthey E, Kumpulainen T. Broadband fluorescence reveals mechanistic differences in excited-state proton transfer to protic and aprotic solvents. Chem Sci 2020; 11:7963-7971. [PMID: 34094165 PMCID: PMC8163259 DOI: 10.1039/d0sc03316b] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Excited-state proton transfer (ESPT) to solvent is often explained according to the two-step Eigen-Weller model including a contact ion pair (CIP*) as an intermediate, but general applicability of the model has not been thoroughly examined. Furthermore, examples of the spectral identification of CIP* are scarce. Here, we report on a detailed investigation of ESPT to protic (H2O, D2O, MeOH and EtOH) and aprotic (DMSO) solvents utilizing a broadband fluorescence technique with sub-200 fs time resolution. The time-resolved spectra are decomposed into contributions from the protonated and deprotonated species and a clear signature of CIP* is identified in DMSO and MeOH. Interestingly, the CIP* intermediate is not observable in aqueous environment although the dynamics in all solvents are multi-exponential. Global analysis based on the Eigen-Weller model is satisfactory in all solvents, but the marked mechanistic differences between aqueous and organic solvents cast doubt on the physical validity of the rate constants obtained.
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Affiliation(s)
- Pragya Verma
- Department of Physical Chemistry, University of Geneva 30 Quai Ernest Ansermet Geneva Switzerland +41 22 379 65 18 +41 22 379 36 58
| | - Arnulf Rosspeintner
- Department of Physical Chemistry, University of Geneva 30 Quai Ernest Ansermet Geneva Switzerland +41 22 379 65 18 +41 22 379 36 58
| | - Bogdan Dereka
- Department of Physical Chemistry, University of Geneva 30 Quai Ernest Ansermet Geneva Switzerland +41 22 379 65 18 +41 22 379 36 58
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva 30 Quai Ernest Ansermet Geneva Switzerland +41 22 379 65 18 +41 22 379 36 58
| | - Tatu Kumpulainen
- Department of Physical Chemistry, University of Geneva 30 Quai Ernest Ansermet Geneva Switzerland +41 22 379 65 18 +41 22 379 36 58
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Delgado-Pinar E, Valente AJ, Sérgio Seixas de Melo J. A comprehensive photophysical and NMR investigation on the interaction of a 4-methylumbelliferone derivative and cucurbit[7]uril. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2018.12.137] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Pina J, de Castro CS, Delgado-Pinar E, Sérgio Seixas de Melo J. Characterization of 4-methylesculetin and of its mono- and di-methoxylated derivatives in water and organic solvents in its ground, singlet and triplet excited states. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.01.083] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Ren G, Meng Q, Zhao J, Chu T. Zwitterions of the excited 4-([2,2′-bipyridine]-4-yl) phenol photoacid molecules: Formation and fluorescence. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.05.052] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Kumpulainen T, Rosspeintner A, Dereka B, Vauthey E. Influence of Solvent Relaxation on Ultrafast Excited-State Proton Transfer to Solvent. J Phys Chem Lett 2017; 8:4516-4521. [PMID: 28872875 DOI: 10.1021/acs.jpclett.7b01956] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A thorough understanding of the microscopic mechanism of excited-state proton transfer (ESPT) and the influence of the solvent environment on its dynamics are of great fundamental interest. We present here a detailed investigation of an ESPT to solvent (DMSO) using time-resolved broadband fluorescence and transient absorption spectroscopies. All excited-state species are resolved spectrally and kinetically using a global target analysis based on the two-step Eigen-Weller model. Reversibility of the initial short-range proton transfer producing excited contact ion pairs (CIP*) is observed unambiguously in fluorescence and must be explicitly considered to obtain the individual rate constants. Close inspection of the early dynamics suggests that the relative populations of the protonated form (ROH*) and CIP* are governed by solvent relaxation that influences the relative energies of the excited states. This constitutes a breakdown of the Eigen-Weller model, although the overall agreement between the data and the analysis using classical rate equations is excellent.
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Affiliation(s)
- Tatu Kumpulainen
- Department of Physical Chemistry, University of Geneva , 30 Quai Ernest Ansermet, Geneva, Switzerland
| | - Arnulf Rosspeintner
- Department of Physical Chemistry, University of Geneva , 30 Quai Ernest Ansermet, Geneva, Switzerland
| | - Bogdan Dereka
- Department of Physical Chemistry, University of Geneva , 30 Quai Ernest Ansermet, Geneva, Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva , 30 Quai Ernest Ansermet, Geneva, Switzerland
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Simkovitch R, Pinto da Silva L, Esteves da Silva JCG, Huppert D. Comparison of the Photoprotolytic Processes of Three 7-Hydroxycoumarins. J Phys Chem B 2016; 120:10297-10310. [DOI: 10.1021/acs.jpcb.6b01383] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Ron Simkovitch
- Raymond
and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | | | | | - Dan Huppert
- Raymond
and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
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Green O, Simkovitch R, Pinto da Silva L, Esteves da Silva JCG, Shabat D, Huppert D. Excited-State Proton Transfer and Formation of the Excited Tautomer of 3-Hydroxypyridine-Dipicolinium Cyanine Dye. J Phys Chem A 2016; 120:6184-99. [DOI: 10.1021/acs.jpca.6b04666] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Ori Green
- Raymond
and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ron Simkovitch
- Raymond
and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | | | | | - Doron Shabat
- Raymond
and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Dan Huppert
- Raymond
and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
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Joung JF, Kim S, Park S. Effect of NaCl Salts on the Activation Energy of Excited-State Proton Transfer Reaction of Coumarin 183. J Phys Chem B 2015; 119:15509-15. [DOI: 10.1021/acs.jpcb.5b09905] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Sangin Kim
- Department of Chemistry, Korea University, Seoul 136-701, Korea
| | - Sungnam Park
- Department of Chemistry, Korea University, Seoul 136-701, Korea
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