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Jang T, Lee S, Pang Y. Anomalous proton transfer of a photoacid HPTS in nonaqueous reverse micelles. Phys Chem Chem Phys 2024; 26:11283-11294. [PMID: 38456549 DOI: 10.1039/d3cp05710k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
The proton transfer reaction is one of the fundamental chemical reactions where the reaction dynamics strongly depend on solvent properties such as acidity or basicity. A photoacid 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) shows a sharp decrease of pKa (7.7 → 0.5) upon photoexcitation, and the excited-state proton transfer (ESPT) occurs with ultrafast time constants of 2.5 and 89 ps in bulk aqueous solution. However, the two-step proton transfers via the contact ion pair formation and the proton diffusion are strongly limited inside the nanopools of reverse micelles (RMs). The confinement in small RMs strongly impeded the proton transfer reactions. In this work, we report the ESPT of HPTS confined in methanol-in-oil RMs by steady-state and time-resolved electronic spectroscopy. Interestingly, HPTS shows substantial deprotonation in the excited state only in small RMs, while the ESPT of HPTS does not occur in bulk methanol solution due to the low basicity of aliphatic alcohols. The kinetic analysis of time-resolved fluorescence and transient absorption measurements will compare the proton transfer dynamics of HPTS in the water-in-oil and methanol-in-oil RMs. The ESPT of photoacids, especially in the nonaqueous RMs, can be crucial in understanding many important chemical reactions involving proton transfer in the confined environments of cells and membranes.
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Affiliation(s)
- Taehyung Jang
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Republic of Korea.
| | - Sebok Lee
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Republic of Korea.
| | - Yoonsoo Pang
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Republic of Korea.
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2
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Sülzner N, Hättig C. Theoretical Study on the Photoacidity of Hydroxypyrene Derivatives in DMSO Using ADC(2) and CC2. J Phys Chem A 2022; 126:5911-5923. [PMID: 36037028 DOI: 10.1021/acs.jpca.2c04436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This work applies the thermodynamic Förster cycle to theoretically investigate the pKa*, i.e., excited-state pKa values of pyranine-derived superphotoacids developed by Jung and co-workers. The latter photoacids are strong enough to transfer a proton to the aprotic solvent dimethyl sulfoxide (DMSO). The Förster cycle provides access to pKa* via the ground-state pKa and the electronic excitation energies. We use the conductor-like screening model for real solvents (COSMO-RS) to compute the ground-state pKa and the correlated wavefunction-based methods ADC(2) and CC2 with the continuum solvation model COSMO to calculate the pKa change upon excitation. A comparison of the calculated UV/Vis absorption and fluorescence emission energies to the experimental results leads us to infer that this approach allows for a proper description of the electronic excitations. In particular, implicit solvation by means of the COSMO model appears to be sufficient for the treatment of these photoacids in DMSO. The calculations confirm the presumption that a charge redistribution from the hydroxy group to the aromatic ring and the electron-withdrawing substituents is the origin of photoacidity for these photoacids. Moreover, the calculations with the continuum solvation model predict that the pKa jump upon excitation decreases with increasing solvent polarity, as rationalized based on the Förster cycle.
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Affiliation(s)
- Niklas Sülzner
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Christof Hättig
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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Joung JF, Lee J, Hwang J, Choi K, Park S. A new visible light triggered Arrhenius photobase and its photo-induced reactions. NEW J CHEM 2020. [DOI: 10.1039/c9nj05404a] [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
Visible light triggered Arrhenius photobases are of potential use for excited state hydroxide ion dissociation (ESHID), photo-induced pOH jump experiments, and base-catalyzed reactions.
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Affiliation(s)
- Joonyoung F. Joung
- Department of Chemistry and Research Institute for Natural Science
- Korea University
- Seoul
- Korea
| | - Jeeun Lee
- Department of Chemistry and Research Institute for Natural Science
- Korea University
- Seoul
- Korea
| | - Joungin Hwang
- Department of Chemistry and Research Institute for Natural Science
- Korea University
- Seoul
- Korea
| | - Kihang Choi
- Department of Chemistry and Research Institute for Natural Science
- Korea University
- Seoul
- Korea
| | - Sungnam Park
- Department of Chemistry and Research Institute for Natural Science
- Korea University
- Seoul
- Korea
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4
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Das S, Singh AK, Biswas DS, Datta A. Dynamics of Preferential Solvation of 5-Aminoquinoline in Hexane–Alcohol Solvent Mixtures. J Phys Chem B 2019; 123:10267-10274. [DOI: 10.1021/acs.jpcb.9b09143] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sharmistha Das
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Avinash Kumar Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Deep Sekhar Biswas
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Anindya Datta
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
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Chakraborty S, Nandi S, Bhattacharyya K, Mukherjee S. Time Evolution of Local pH Around a Photo-Acid in Water and a Polymer Hydrogel: Time Resolved Fluorescence Spectroscopy of Pyranine. Chemphyschem 2019; 20:3221-3227. [PMID: 31596029 DOI: 10.1002/cphc.201900845] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 09/19/2019] [Indexed: 12/31/2022]
Abstract
In this work, we propose a new analysis of the time resolved emission spectra of a photo-acid, HA, pyranine (8-hydroxypyrene-1,3,6-trisulphonic acid, HPTS) based on time resolved area normalized emission spectra (TRANES). Presence of an isoemissive point in TRANES confirms the presence of two emissive species (HA and A- ) inside the system in bulk water and inside a co-polymer hydrogel [F127, (PEO)100 -(PPO)70 -(PEO)100 ]. We show that following electronic excitation, the local pH around HPTS, is much lower than the bulk pH presumably because of ejection of proton from the photo-acid in the excited state. With increase in time, the local pH increases and reaches the bulk value. We further, demonstrate that the excited state pKa of HPTS may be estimated from the emission intensities of HA and A- at long time. The time constant for time evolution of pH is ∼630 ps in water, ∼1300 ps in F127 gel and ∼4700 ps in CTAB micelle. The location and local viscosity sensed by the probe is ascertained using fluorescence correlation spectroscopy (FCS) and fluorescence anisotropy decay. The different values of the local viscosity reported by these two methods are reconciled.
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Affiliation(s)
- Subhajit Chakraborty
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhopal, 462 066, Madhya Pradesh, India
| | - Somen Nandi
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhopal, 462 066, Madhya Pradesh, India
| | - Kankan Bhattacharyya
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhopal, 462 066, Madhya Pradesh, India
| | - Saptarshi Mukherjee
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhopal, 462 066, Madhya Pradesh, India
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Analysis of excited state proton transfer dynamics of HPTS in methanol-water mixtures from time-resolved area-normalised emission spectrum (TRANES). J Photochem Photobiol A Chem 2019. [DOI: 10.1016/j.jphotochem.2019.01.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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7
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Bertozo LDC, Philot EA, Lima AN, de Resende Lara PT, Scott AL, Ximenes VF. Interaction between 1-pyrenesulfonic acid and albumin: Moving inside the protein. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 208:243-254. [PMID: 30342339 DOI: 10.1016/j.saa.2018.10.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 10/04/2018] [Accepted: 10/11/2018] [Indexed: 06/08/2023]
Abstract
Due to the high sensitivity to alterations in microenvironment polarity of macromolecules, pyrene and its derivatives have long been applied in biosciences. Human serum albumin (HSA), besides its numerous physiological functions, is the main responsible by transport of endogenous and exogenous compounds in the circulatory system. Here, a comprehensive study was carry out to understand the interaction between HSA and the pyrene derivative 1-pyrenesulfonic acid (PMS), which showed a singular behaviour when bound to this protein. The complexation of PMS with HSA was studied by steady state, time-resolved and anisotropy fluorescence, induction of circular dichroism (ICD) and molecular docking. The fluorescence quenching of PMS by HSA was abnormal, being stronger at lower concentration of the quencher. Similar behaviour was obtained by measuring the ICD signal and fluorescence lifetime of PMS complexed in HSA. The displacement of PMS by site-specific drugs showed that this probe occupied both sites, but with higher affinity for site II. The movement of PMS between these main binding sites was responsible by the abnormal effect. Using the holo (PDB: ID 1A06) and apo (PDB: ID 1E7A) HSA structures, the experimental results were corroborated by molecular docking simulation. The abnormal spectroscopic behaviour of PMS is related to its binding in different regions in the protein. The movement of PMS into the protein can be traced by alteration in the spectroscopic signals. These findings bring a new point of view about the use of fluorescence quenching to characterize the interaction between albumin and ligands.
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Affiliation(s)
- Luiza de Carvalho Bertozo
- Department of Chemistry, Faculty of Sciences, UNESP - São Paulo State University, 17033-360 Bauru, SP, Brazil
| | - Eric Allison Philot
- Laboratory of Computational Biology and Bioinformatics, UFABC - Federal University of ABC, 09210-580 Santo André, SP, Brazil
| | - Angélica Nakagawa Lima
- Laboratory of Computational Biology and Bioinformatics, UFABC - Federal University of ABC, 09210-580 Santo André, SP, Brazil
| | - Pedro Túlio de Resende Lara
- Laboratory of Computational Biology and Bioinformatics, UFABC - Federal University of ABC, 09210-580 Santo André, SP, Brazil
| | - Ana Lígia Scott
- Laboratory of Computational Biology and Bioinformatics, UFABC - Federal University of ABC, 09210-580 Santo André, SP, Brazil
| | - Valdecir Farias Ximenes
- Department of Chemistry, Faculty of Sciences, UNESP - São Paulo State University, 17033-360 Bauru, SP, Brazil.
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Sahu K, Nandi N, Dolai S, Bera A. A Ratio-Analysis Method for the Dynamics of Excited State Proton Transfer: Pyranine in Water and Micelles. J Phys Chem B 2018; 122:6610-6615. [DOI: 10.1021/acs.jpcb.8b04271] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kalyanasis Sahu
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Nilanjana Nandi
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Suman Dolai
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Avisek Bera
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
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