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Samanta P, Dutta Choudhury S, Pal H. Kinetics and Energetics of Ultrafast Bimolecular Photoinduced Electron Transfer Reactions in Pluronic-Surfactant Supramolecular Assemblies. J Phys Chem B 2019; 123:5942-5953. [PMID: 31246469 DOI: 10.1021/acs.jpcb.9b04223] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Understanding the kinetics and energetics of photoinduced electron transfer (PET) reactions in constrained media has attracted considerable research interest, as constrained media provide a handle to tune the microenvironments and consequently the mechanisms of PET reactions. In this study, PET reactions between excited 7-aminocoumarin acceptors and ground-state N,N-dimethylaniline (DMAN) donor have been investigated in mixed micellar media composed of triblock copolymer, P123, and anionic surfactant, sodium dodecyl sulfate (SDS), with varying SDS-to-P123 molar ratios (n values). The objective is to elucidate the role of the n values in the rates and energetics of PET reactions over the entire time range from the subpicosecond to the subnanosecond domain, especially in regard to the applicability of the two-dimensional ET (2DET) mechanism. It is observed that by changing the n values, there is a significant change in the hydration characteristics of the SDS-P123 mixed micelles, which in turn changes the kinetics to energetic correlations for the PET reactions. Fluorescence from the excited coumarin acceptors undergoes substantial quenching due to PET from DMAN donor in all of the studied micelles as evidenced from steady-state, subnanosecond time-resolved (TR) and ultrafast (subpicosecond/femtosecond) fluorescence up-conversion measurements. The quenching rate constants (kq), estimated from subnanosecond TR fluorescence studies, and the individual component-wise decay rates (τi-1), estimated from up-conversion measurements, increase gradually with increasing n value, corroborating well with the sequentially increased micropolarity of the mixed micelles. Interestingly, it is observed that the correlations of either kq (from subnanosecond studies) or τi-1 (from femtosecond studies) with the reaction exergonicity (-ΔG°) show the noteworthy Marcus inversion (MI) behavior in a very consistent and similar manner for the entire time window, from subpicoseconds to subnanoseconds. The onset of MI always appears at an exergonicity (-ΔG°MI) much lower than solvent reorganization energy (λs), suggesting the involvement of 2DET mechanism throughout the subpicosecond to subnanosecond time domains. The present results thus provide a comprehensive picture of the kinetics and energetics of the PET reactions in constrained media for the whole time span and unequivocally establish the applicability of 2DET mechanism for the PET reactions in constrained media, eliminating any apprehensions about the effect of time resolution of the subnanosecond setup on the observed Marcus inversion behavior. This is indeed an important finding, providing valuable insights for PET reactions in constrained media, which has not been explored explicitly in any of the previous studies. Observation of MI behavior and the modulations in the PET reactions by simply changing the composition of SDS in the SDS-P123 mixed micelles are noteworthy findings of the present study and are expected to find suitable applications for better utilization and outcome of the PET reactions.
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Affiliation(s)
- Papu Samanta
- Homi Bhabha National Institute , Training School Complex , Anushaktinagar, Mumbai 400094 , India
| | | | - Haridas Pal
- Homi Bhabha National Institute , Training School Complex , Anushaktinagar, Mumbai 400094 , India
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2
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Tarif E, Saha B, Mukherjee K, De P, Biswas R. Exploring Aqueous Solution Dynamics of an Amphiphilic Diblock Copolymer: Dielectric Relaxation and Time-Resolved Fluorescence Measurements. J Phys Chem B 2019; 123:5892-5901. [DOI: 10.1021/acs.jpcb.9b00889] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ejaj Tarif
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Biswajit Saha
- Polymer Research Centre and Centre for Advanced Functional Materials, Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia 741246, West Bengal, India
| | - Kallol Mukherjee
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Priyadarsi De
- Polymer Research Centre and Centre for Advanced Functional Materials, Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia 741246, West Bengal, India
| | - Ranjit Biswas
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
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3
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Gupta S, Chakraborty A, Sen P. Elucidation of intriguing methanol-dichloromethane binary solvent mixture: Synergistic effect, analytical modeling, NMR and photo-induced electron transfer studies. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2016.08.048] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Kumbhakar M, Pal H. Reply to "Comment on 'Observation of the Marcus Inverted Region for Bimolecular Photoinduced Electron-Transfer Reactions in Viscous Media'". J Phys Chem B 2016; 120:9804-9. [PMID: 27537065 DOI: 10.1021/acs.jpcb.6b07633] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Manoj Kumbhakar
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre , Trombay, Mumbai 400 085, India
| | - Haridas Pal
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre , Trombay, Mumbai 400 085, India
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5
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Mukherjee P, Biswas S, Sen P. Real Time Quantification of Ultrafast Photoinduced Bimolecular Electron Transfer Rate: Direct Probing of the Transient Intermediate. J Phys Chem B 2015; 119:11253-61. [DOI: 10.1021/acs.jpcb.5b03105] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Puspal Mukherjee
- Department
of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, Uttar Pradesh, India
| | - Somnath Biswas
- Department
of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, Uttar Pradesh, India
| | - Pratik Sen
- Department
of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, Uttar Pradesh, India
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Kuchlyan J, Banik D, Kundu N, Roy A, Sarkar N. Interaction of fluorescence dyes with 5-fluorouracil: A photoinduced electron transfer study in bulk and biologically relevant water. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.08.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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7
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Abstract
Electron transfer between redox proteins participating in energy chains of biology is required to proceed with high energetic efficiency, minimizing losses of redox energy to heat. Within the standard models of electron transfer, this requirement, combined with the need for unidirectional (preferably activationless) transitions, is translated into the need to minimize the reorganization energy of electron transfer. This design program is, however, unrealistic for proteins whose active sites are typically positioned close to the polar and flexible protein-water interface to allow inter-protein electron tunneling. The high flexibility of the interfacial region makes both the hydration water and the surface protein layer act as highly polar solvents. The reorganization energy, as measured by fluctuations, is not minimized, but rather maximized in this region. Natural systems in fact utilize the broad breadth of interfacial electrostatic fluctuations, but in the ways not anticipated by the standard models based on equilibrium thermodynamics. The combination of the broad spectrum of static fluctuations with their dispersive dynamics offers the mechanism of dynamical freezing (ergodicity breaking) of subsets of nuclear modes on the time of reaction/residence of the electron at a redox cofactor. The separation of time-scales of nuclear modes coupled to electron transfer allows dynamical freezing. In particular, the separation between the relaxation time of electro-elastic fluctuations of the interface and the time of conformational transitions of the protein caused by changing redox state results in dynamical freezing of the latter for sufficiently fast electron transfer. The observable consequence of this dynamical freezing is significantly different reorganization energies describing the curvature at the bottom of electron-transfer free energy surfaces (large) and the distance between their minima (Stokes shift, small). The ratio of the two reorganization energies establishes the parameter by which the energetic efficiency of protein electron transfer is increased relative to the standard expectations, thus minimizing losses of energy to heat. Energetically efficient electron transfer occurs in a chain of conformationally quenched cofactors and is characterized by flattened free energy surfaces, reminiscent of the flat and rugged landscape at the stability basin of a folded protein.
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Affiliation(s)
- Dmitry V Matyushov
- Center for Biological Physics, Arizona State University, PO Box 871504, Tempe, Arizona 85287-1504, USA.
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Swaminathan S, Garcia-Amorós J, Fraix A, Kandoth N, Sortino S, Raymo FM. Photoresponsive polymer nanocarriers with multifunctional cargo. Chem Soc Rev 2014; 43:4167-78. [DOI: 10.1039/c3cs60324e] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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9
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Photoinduced electron transfer between coumarin dyes and N,N-dimethylaniline in imidazolium based room temperature ionic liquids: Effect of the cation's alkyl chain length on the bimolecular photoinduced electron transfer process. J Photochem Photobiol A Chem 2013. [DOI: 10.1016/j.jphotochem.2013.03.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lopez-Lopez M, Sanchez F, Marchena M. Determination of Reaction and Reorganization Free Energies of Electron Transfer Reactions under Restricted Geometry Conditions. PROGRESS IN REACTION KINETICS AND MECHANISM 2012. [DOI: 10.3184/146867812x13382026560489] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this paper, different methods of obtaining the two parameters controlling the rate of electron transfer processes (reaction and reorganization free energies, Λ and Δ G0’, respectively) under restricted geometry conditions are considered. The main difficulty of accomplishing this comes from lack of knowledge of the properties in the interfacial region, where the reaction occurs. A general method has been presented and illustrated with the study of intermolecular processes in micelles. This method is optimized when the free energies for (at least) the three reactions required are quite different. For excited state electron transfer, the general approach is based on the appearance of the so-called Marcus inverted region: at the starting point of this region the value of Δ G0’ gives the value of Λ directly. These reaction free energies also present some uncertainties because in their calculation it is necessary to know the value of the local dielectric constant. Finally, it should be mentioned that some authors have suggested that the treatments for electron transfer reactions could not be applicable under restricted conditions. However, experiments do seem to show the applicability of the Marcus-Hush treatment under these conditions.
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Affiliation(s)
- Manuel Lopez-Lopez
- The Department of Physical Chemistry. University of Seville. c/Profesor García González s/n. 41012 Sevilla. Spain
| | - Francisco Sanchez
- The Department of Physical Chemistry. University of Seville. c/Profesor García González s/n. 41012 Sevilla. Spain
| | - María Marchena
- The Department of Physical Chemistry. University of Seville. c/Profesor García González s/n. 41012 Sevilla. Spain
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Sarkar S, Mandal S, Ghatak C, Rao VG, Ghosh S, Sarkar N. Photoinduced Electron Transfer in an Imidazolium Ionic Liquid and in Its Binary Mixtures with Water, Methanol, and 2-Propanol: Appearance of Marcus-Type of Inversion. J Phys Chem B 2012; 116:1335-44. [DOI: 10.1021/jp2075995] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Souravi Sarkar
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
| | - Sarthak Mandal
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
| | - Chiranjib Ghatak
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
| | - Vishal Govind Rao
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
| | - Surajit Ghosh
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
| | - Nilmoni Sarkar
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
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12
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Sarkar S, Mandal S, Pramanik R, Ghatak C, Rao VG, Sarkar N. Photoinduced Electron Transfer in a Room Temperature Ionic Liquid 1-Butyl-3-methylimidazolium Octyl Sulfate Micelle: A Temperature Dependent Study. J Phys Chem B 2011; 115:6100-10. [DOI: 10.1021/jp201702x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Souravi Sarkar
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
| | - Sarthak Mandal
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
| | - Rajib Pramanik
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
| | - Chiranjib Ghatak
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
| | - Vishal Govind Rao
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
| | - Nilmoni Sarkar
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
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13
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Sarkar S, Pramanik R, Ghatak C, Rao VG, Sarkar N. Characterization of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][Tf2N])/TX-100/cyclohexane ternary microemulsion: Investigation of photoinduced electron transfer in this RTIL containing microemulsion. J Chem Phys 2011; 134:074507. [DOI: 10.1063/1.3548834] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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14
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Kumbhakar M, Dey S, Singh PK, Nath S, Satpati AK, Gangully R, Aswal VK, Pal H. Tuning of Intermolecular Electron Transfer Reaction by Modulating the Microenvironment Inside Copolymer−Surfactant Supramolecular Assemblies. J Phys Chem B 2011; 115:1638-51. [DOI: 10.1021/jp109217v] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
| | - Swayandipta Dey
- Chemistry Department, Pondicherry University, Kalapet, Pondicherry 605014, India
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15
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Mondal T, Das AK, Sasmal DK, Bhattacharyya K. Excited State Proton Transfer in Ionic Liquid Mixed Micelles. J Phys Chem B 2010; 114:13136-42. [DOI: 10.1021/jp1058758] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tridib Mondal
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Atanu Kumar Das
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Dibyendu Kumar Sasmal
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Kankan Bhattacharyya
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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16
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Kumbhakar M, Singh PK, Satpati AK, Nath S, Pal H. Ultrafast Electron Transfer Dynamics in Micellar Media Using Surfactant as the Intrinsic Electron Acceptor. J Phys Chem B 2010; 114:10057-65. [DOI: 10.1021/jp102258y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Manoj Kumbhakar
- Radiation & Photochemistry Division, and Analytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Prabhat Kumar Singh
- Radiation & Photochemistry Division, and Analytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Ashis Kumar Satpati
- Radiation & Photochemistry Division, and Analytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Sukhendu Nath
- Radiation & Photochemistry Division, and Analytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Haridas Pal
- Radiation & Photochemistry Division, and Analytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
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17
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Bhattacharya B, Nakka S, Guruprasad L, Samanta A. Interaction of bovine serum albumin with dipolar molecules: fluorescence and molecular docking studies. J Phys Chem B 2009; 113:2143-50. [PMID: 19199686 DOI: 10.1021/jp808611b] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Interaction of bovine serum albumin (BSA) with two series of dipolar molecules having both rigid and flexible structures has been studied by monitoring the spectral and temporal behavior of the intramolecular charge transfer fluorescence of the systems. The binding sites of the molecular systems in BSA have been located with the help of docking studies. Three different sites of varying hydrophobicity have been identified where these molecules are located. Binding in the hydrophobic domains of BSA leads to a blue shift of the fluorescence spectra and an enhancement of fluorescence intensity and lifetime. This enhancement is found to be the largest for flexible systems in which internal motion serves as a nonradiative decay route. In the BSA-bound condition, some of the dipolar molecules exhibit not-so-common "dip-rise-dip" time-resolved fluorescence anisotropy profiles. It is shown that a large difference of the fluorescence lifetimes of the protein-bound and unbound molecules is one of the factors that contributes to this kind of anisotropy profiles. As internal motion is often responsible for the short fluorescence lifetime of the flexible dipolar molecules, a large increase in the fluorescence lifetime of these systems occurs if binding to BSA leads to disruption/prevention of this motion. It thus appears that it might be possible to obtain information on the prevention/disruption of nonradiative pathway on protein binding from the anisotropy profiles of the kind discussed above. However, since the present study reveals cases where a large change in fluorescence lifetime also occurs due to other reasons, one needs to be careful prior to making any conclusion.
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