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Lakshmi SN, Bahadur P, Choudhury SD. Fate of Photoinduced Electron Transfer Reactions with Temperature- and pH-Induced Assembly/Disassembly of Star Block Copolymer Micelles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:14125-14134. [PMID: 34797674 DOI: 10.1021/acs.langmuir.1c02383] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The assembly/disassembly of star block copolymers induced by changes in temperature or pH of the medium is anticipated to have interesting implications for hosting/releasing drugs and tuning chemical reactions. This study investigates the possibility of employing the dually sensitive self-assembly of an ethylene oxide-propylene oxide star block copolymer, Tetronic T904, to influence photoinduced electron transfer (ET) reactions, on switching from the assembled state (micelle) when temperature is above the critical micelle temperature (CMT) and pH of the medium is above the pKa of T904 to the dissociated (unimer) state when either the temperature is below the CMT or the polymer is protonated. Steady-state and time-resolved fluorescence techniques have been used to characterize the microenvironments of the reactants in T904 solutions under different temperature and pH conditions and to determine ET rate constants. Interestingly, the bimolecular ET rate constants in both assembled and disassembled states of T904 depict a bell-shaped correlation with the driving force of the reaction, in accordance with Marcus inversion behavior instead of the usual Rehm-Weller behavior seen in conventional solvents. The assembly/disassembly of T904 stimulated by temperature or pH affects the micropolarity in the reactant environment, the magnitude of ET rate constants, and the position of inversion on the exergonicity scale.
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Affiliation(s)
- Suresh Nayana Lakshmi
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Pratap Bahadur
- Department of Chemistry, Veer Narmad South Gujarat University, Surat 395007, India
| | - Sharmistha Dutta Choudhury
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India
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2
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Photoinduced electron transfer reactions in mixed micelles of a star block copolymer and surface active ionic liquids: Role of the anion. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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3
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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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4
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Samanta P, Halder P, Bahadur P, Dutta Choudhury S, Pal H. Effect of Ionic Liquids as Cosurfactants on Photoinduced Electron Transfer in Tetronic Micelles. J Phys Chem B 2018; 122:10190-10201. [PMID: 30351120 DOI: 10.1021/acs.jpcb.8b08766] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study investigates the role of varying alkyl chain lengths of a series of surface-active 1-alkyl-3-methylimidazolium tetrafluoroborate ([C nMIm][BF4], n = 4, 6, and 10) ionic liquids (ILs) as cosurfactants in modifying the micellar characteristics of a tetronic star-block copolymer, T1304, and the consequent effects on bimolecular photoinduced electron transfer (PET) reactions carried out in these T1304-IL mixed micellar systems. Using coumarin 153 as the probe dye and following ground-state absorption, steady-state fluorescence, and time-resolved emission measurements, the micropolarity, microviscosity, and solvent relaxation dynamics in the micellar palisade layer have been revealed both in pure T1304 and in T1304-IL systems. With increasing alkyl chain length of the ILs, the palisade layer of the micelles gradually becomes more polar and less viscous, suggesting better incorporation of the longer alkyl chain length ILs as cosurfactants into the T1304 micelles. The bimolecular PET reactions, involving 7-aminocoumarins as acceptors and N, N-dimethylaniline as the donor, are considerably modulated in T1304 micelles by the presence of the ILs, the effect being more prominent for ILs with longer alkyl chain lengths. In all of the micellar systems, correlations of the electron transfer (ET) kinetics with the reaction exergonicity (-Δ G0) show clear Marcus inversion (MI) behavior where onsets of MI invariably appear at significantly lower exergonicities, suggesting the involvement of a two-dimensional ET mechanism. Interestingly, the Marcus correlations display significant variations, namely, enhanced reaction rates and gradual shift in the onset of MI toward higher exergonicity, as longer alkyl chain length ILs are sequentially introduced as cosurfactants. From the observed results, it is convincingly realized that 1-alkyl-3-methylimidazolium-based ILs can be used satisfactorily as cosurfactants in tetronic star-block copolymer solutions to modulate PET reactions very significantly for their better utilizations in suitable applied areas.
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Affiliation(s)
- Papu Samanta
- Homi Bhabha National Institute , Training School Complex , Anushaktinagar, Mumbai 400094 , India
| | | | - Pratap Bahadur
- Department of Chemistry , Veer Narmad South Gujarat University , Surat 395007 , India
| | | | - Haridas Pal
- Homi Bhabha National Institute , Training School Complex , Anushaktinagar, Mumbai 400094 , India
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5
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Samanta P, Rane S, Bahadur P, Dutta Choudhury S, Pal H. Tetronic Star Block Copolymer Micelles: Photophysical Characterization of Microenvironments and Applicability for Tuning Electron Transfer Reactions. J Phys Chem B 2018; 122:6079-6093. [DOI: 10.1021/acs.jpcb.8b01778] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Papu Samanta
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India
| | | | - Pratap Bahadur
- Department of Chemistry, Veer Narmad South Gujarat University, Surat 395007, India
| | | | - Haridas Pal
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India
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6
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Mukherjee P, Das A, Sengupta A, Sen P. Bimolecular Photoinduced Electron Transfer in Static Quenching Regime: Illustration of Marcus Inversion in Micelle. J Phys Chem B 2017; 121:1610-1622. [PMID: 28140599 DOI: 10.1021/acs.jpcb.6b11206] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ultrafast bimolecular photoinduced electron transfer (PET) between six coumarin dyes and four viologen molecules in the stern layer of sodium dodecyl sulfate micelle have been studied using femtosecond broadband transient absorption spectroscopy and femtosecond fluorescence up-conversion spectroscopy over a broad reaction exergonicity (ΔG0). Emanating the formation of radical cation intermediates of viologen molecules using the transient absorption and the fast decay component of coumarins using the fluorescence up-conversion studies the forward bimolecular electron transfer rate (ket) have been measured with high accuracy. The relationship of ket with ΔG0 found to follow a Marcus type bell-shaped dependence with an inversion at -1.10 eV. In this report, we have studied PET reaction using ultrafast spectroscopy at the quencher concentration where static quenching regime prevails. Moreover, the incompetency of Stern-Volmer experiments in studying ultrafast PET has been revealed. In contrary to previous claims, here we found that the ket is lower for lower lifetime coumarins, indicating that static, nonstationary and stationary regime of quenching have the minimal role to play to in the bimolecular electron transfer process. By far, this report is believed to be the most efficient and immaculate way of approaching Marcus inverted region problem in the case of bimolecular PET and settles the long-lasting debate of whether the same can be observed in micellar systems.
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Affiliation(s)
- Puspal Mukherjee
- Department of Chemistry, Indian Institute of Technology Kanpur , Kanpur 208 016, UP, India
| | - Aritra Das
- Department of Chemistry, Indian Institute of Technology Kanpur , Kanpur 208 016, UP, India
| | - Arunava Sengupta
- Department of Chemistry, Indian Institute of Technology Kanpur , Kanpur 208 016, UP, India
| | - Pratik Sen
- Department of Chemistry, Indian Institute of Technology Kanpur , Kanpur 208 016, UP, India
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7
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Jana B, Inamdar SR, H M SK. Effect of quencher and temperature on fluorescence intensity of laser dyes: DETC and C504T. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 170:124-130. [PMID: 27423111 DOI: 10.1016/j.saa.2016.07.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 07/01/2016] [Accepted: 07/06/2016] [Indexed: 06/06/2023]
Abstract
Fluorescence quenching of 7- Diethylamino-3-thenoylcoumarin (DETC) and 2,3,6,7-tetrahydro-1,1,7,7-tetramethyl11-oxo-1H,5H,11H- [1]benzopyrano[6,7,8-ij]quinolizine-10-carboxylic acid, ethyl ester (C504T) by aniline(AN), dimethylaniline (DMA) and diethylaniline (DEA) was investigated in toluene by steady state and transient methods. The quenching parameters like frequency of encounter (kd), probability of quenching per encounter (p), quenching rate parameters (kq) and activation energy of quenching (Ea) were determined experimentally. The kq values determined by steady state and time-resolved methods for the both dyes were found to be same, indicating the dynamic nature of interaction. Magnitudes of p and Ea suggested that the quenching reaction is predominantly controlled by material diffusion. The quenching mechanism is rationalized in terms of electron transfer (ET) from donors (aromatic amines) to the acceptors (coumarin derivatives) confirmed by correlating kq with free energy changes (ΔG°). Further, an effect of temperature on fluorescence intensity was carried out in toluene and methanol solvents. Fluorescence intensity of both the dyes decreases with increase in temperature. Temperature quenching in case of C504T is due to intersystem crossing S1→T2, whereas for DETC, quenching is due to intersystem crossing S1→T2 and ICT→TICT transition.
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Affiliation(s)
- Basavaraja Jana
- Department of Physics, Siddaganga Institute of Technology, Tumkur 572 103, India
| | - S R Inamdar
- Laser Spectroscopy Programme, Department of Physics, Karnatak University, Dharwad 580003, India
| | - Suresh Kumar H M
- Department of Physics, Siddaganga Institute of Technology, Tumkur 572 103, India.
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8
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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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9
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Kuchlyan J, Kundu N, sarkar N. Ionic liquids in microemulsions: Formulation and characterization. Curr Opin Colloid Interface Sci 2016. [DOI: 10.1016/j.cocis.2016.05.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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Effect of viscosity on photoinduced electron transfer reaction: An observation of the Marcus inverted region in homogeneous solvents. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Nanda R. Unusual linear dependency of viscosity with temperature in ionic liquid/water mixtures. Phys Chem Chem Phys 2016; 18:25801-25805. [DOI: 10.1039/c6cp05257f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The unusual linear scaling of the self-diffusion coefficient and viscosity leads to the violation of the SE and FSE equations and shows dynamic heterogeneity.
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Affiliation(s)
- R. Nanda
- Department of Physical Science
- Indian Institute of Science Education and Research
- Mohali
- India
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12
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Barman N, Singha D, Sahu K. Faster photoinduced electron transfer in a diluted mixture than in a neat donor solvent: effect of excited-state H-bonding. Phys Chem Chem Phys 2015; 16:6159-66. [PMID: 24562294 DOI: 10.1039/c4cp00025k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In a neat electron-donating solvent (in this case aniline), photoinduced electron transfer (PET) from the solvent to an excited acceptor (e.g. a coumarin fluorophore) may be anticipated to be the most efficient because of the close contact of the acceptor with many donors. Addition of an inert component would most likely retard the PET process by replacing some donors from the neighbourhood of the acceptors. Surprisingly, we found dramatic acceleration of PET (6-10 fold enhancement compared to neat aniline), for coumarin 102 (C102) dissolved in a binary mixture of aniline and an inert solvent (cyclohexane or toluene). The PET induced fluorescence follows an anomalous trend against the mole fraction of aniline (XAN); first quenches up to certain XAN (0.075 for cyclohexane; 0.13 for toluene), thereafter, enhances with increase in XAN. Although the non-interacting component cannot directly participate in the PET process, it may modulate C102-aniline H-bonding association by changing the polarity of the medium or by disrupting the aniline-aniline H-bond. The study clearly illustrates the dominant role of hydrogen bonding in activating the electron transfer rate where standard thermodynamics predicts very weak donor-acceptor interaction.
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Affiliation(s)
- Nabajeet Barman
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
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13
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14
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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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15
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Kumbhakar M, Manna A, Sayed M, Kumar A, Pal H. Observation of the Marcus Inverted Region for Bimolecular Photoinduced Electron-Transfer Reactions in Viscous Media. J Phys Chem B 2014; 118:10704-15. [DOI: 10.1021/jp506885r] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Manoj Kumbhakar
- Radiation
and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Arpan Manna
- Physical
and Material Chemistry Division, CSIR-National Chemical Laboratory, H. J. Bhabha Road, Pune 411 008, India
| | - Mhejabeen Sayed
- Radiation
and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Anil Kumar
- Physical
and Material Chemistry Division, CSIR-National Chemical Laboratory, H. J. Bhabha Road, Pune 411 008, India
| | - Haridas Pal
- Radiation
and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
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16
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Cooper JK, Benjamin I. Photoinduced Excited State Electron Transfer at Liquid/Liquid Interfaces. J Phys Chem B 2014; 118:7703-14. [DOI: 10.1021/jp409541u] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jason K. Cooper
- Department
of Chemistry and
Biochemistry University of California Santa Cruz, California 95064, United States
| | - Ilan Benjamin
- Department
of Chemistry and
Biochemistry University of California Santa Cruz, California 95064, United States
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17
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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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18
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Johnson MD, Lorenz BB, Wilkins PC, Lemons BG, Baruah B, Lamborn N, Stahla M, Chatterjee PB, Richens DT, Crans DC. Switching Off Electron Transfer Reactions in Confined Media: Reduction of [Co(dipic)2]− and [Co(edta)]− by Hexacyanoferrate(II). Inorg Chem 2012; 51:2757-65. [DOI: 10.1021/ic201247v] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michael D. Johnson
- Department
of Chemistry and
Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003-8001, United States
| | - Bret B. Lorenz
- Department
of Chemistry and
Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003-8001, United States
| | - Patricia C. Wilkins
- Department
of Chemistry and
Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003-8001, United States
| | - Brant G. Lemons
- Department
of Chemistry and
Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003-8001, United States
| | - Bharat Baruah
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872,
United States
| | - Nathan Lamborn
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872,
United States
| | - Michelle Stahla
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872,
United States
| | - Pabitra B. Chatterjee
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872,
United States
| | - David T. Richens
- Department
of Chemistry and
Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003-8001, United States
| | - Debbie C. Crans
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872,
United States
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19
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Ghatak C, Rao VG, Mandal S, Sarkar N. Photoinduced electron transfer between various coumarin analogues and N,N-dimethylaniline inside niosome, a nonionic innocuous polyethylene glycol-based surfactant assembly. Phys Chem Chem Phys 2012; 14:8925-35. [DOI: 10.1039/c2cp23209j] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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20
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Silva OF, Fernández MA, Silber JJ, de Rossi RH, Correa NM. Inhibited Phenol Ionization in Reverse Micelles: Confinement Effect at the Nanometer Scale. Chemphyschem 2011; 13:124-30. [DOI: 10.1002/cphc.201100634] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 10/05/2011] [Indexed: 11/11/2022]
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21
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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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22
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Photoinduced intermolecular electron transfer in a room temperature imidazolium ionic liquid: An excitation wavelength dependence study. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.03.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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23
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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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24
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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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25
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Chakraborty B, Basu S. Interaction of proflavin with aromatic amines in homogeneous and micellar media: Photoinduced electron transfer probed by magnetic field effect. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.01.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Abstract
Recent advances in ultrafast laser technology have spurred investigations of microheterogeneous solutions. In particular, researchers have explored details of reverse micelles (RMs), which present isolated droplets of polar solvent sequestered from a continuous nonpolar phase by a surfactant layer. This review explores recent studies utilizing a variety of ultrafast laser techniques to uncover details about structure and dynamics in various RMs. Using ultrafast vibrational spectroscopy, researchers have probed hydrogen-bond dynamics and vibrational energy relaxation in RMs. These studies have developed our understanding of reverse micellar structure, identifying varying water environments in the RMs. In a plethora of experiments employing probe molecules, researchers have explored the confined environment presented by RMs and their impact on a range of chemical reactions. These studies have shown that confinement, rather than the specific interactions with surfactants, is an important factor determining the impact of the reverse micellar environment on the chemistry.
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Affiliation(s)
- Nancy E Levinger
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA.
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The use of coumarins as environmentally-sensitive fluorescent probes of heterogeneous inclusion systems. Molecules 2009; 14:210-37. [PMID: 19127249 PMCID: PMC6253935 DOI: 10.3390/molecules14010210] [Citation(s) in RCA: 310] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 12/23/2008] [Accepted: 01/04/2009] [Indexed: 11/16/2022] Open
Abstract
Coumarins, as a family of molecules, exhibit a wide range of fluorescence emission properties. In many cases, this fluorescence is extremely sensitive to the local environment of the molecule, especially the local polarity and microviscosity. In addition, coumarins show a wide range of size, shape, and hydrophobicity. These properties make them especially useful as fluorescent probes of heterogeneous environments, such as supramolecular host cavities, micelles, polymers and solids. This article will review the use of coumarins to probe such heterogeneous systems using fluorescence spectroscopy.
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Stahla ML, Baruah B, James DM, Johnson MD, Levinger NE, Crans DC. 1H NMR studies of aerosol-OT reverse micelles with alkali and magnesium counterions: preparation and analysis of MAOTs. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:6027-6035. [PMID: 18484757 DOI: 10.1021/la8002965] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Simple procedures and characterization of a series of well-defined precursors are described for preparation of a unique microenvironment in nanoreactors, reverse micelles. The Na(+), K(+), Rb(+), Cs(+), and Mg(2+) surfactants were prepared using liquid-liquid ion exchange using chloride and nitrate salts. The surfactants were characterized using (1)H NMR spectroscopy and a variety of other techniques. (1)H NMR spectroscopy was found to be a sensitive probe for characterization of the size of the nanoreactor as well as its water content. (1)H NMR spectra can be used for detailed characterization of reactions in confined environments when counterion effects are likely to be important. (1)H NMR spectroscopy revealed two separate peaks corresponding to water in Mg(AOT)2 samples; one peak arises from water coordinated to the Mg(2+) ion while the other peak arises from bulk water. The two water signals arise directly from the slow exchange of the water coordinated to Mg(2+) in these microemulsions with water in the water pool, and provide an opportunity to study hydration of Mg(2+). This work thus extends the potential use of MAOT microemulsions for applications such as in green chemistry.
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Affiliation(s)
- Michelle L Stahla
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA
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Kumbhakar M, Singh PK, Nath S, Bhasikuttan AC, Pal H. Ultrafast Bimolecular Electron Transfer Dynamics in Micellar Media. J Phys Chem B 2008; 112:6646-52. [DOI: 10.1021/jp800752d] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Manoj Kumbhakar
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Prabhat K. Singh
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Sukhendu Nath
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | | | - Haridas Pal
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
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Kumar CV, Duff, Jr. MR. Towards building artificial light harvesting complexes: enhanced singlet–singlet energy transfer between donor and acceptor pairs bound to albumins. Photochem Photobiol Sci 2008; 7:1522-30. [DOI: 10.1039/b811091c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fernández E, García-Río L, Rodríguez-Dafonte P. Degree of counterion binding on water in oil microemulsions. J Colloid Interface Sci 2007; 316:1023-6. [DOI: 10.1016/j.jcis.2007.09.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 09/03/2007] [Accepted: 09/07/2007] [Indexed: 10/22/2022]
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Choudhury SD, Kumbhakar M, Nath S, Pal H. Photoinduced bimolecular electron transfer kinetics in small unilamellar vesicles. J Chem Phys 2007; 127:194901. [DOI: 10.1063/1.2794765] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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Choudhury SD, Kumbhakar M, Nath S, Sarkar SK, Mukherjee T, Pal H. Compartmentalization of Reactants in Different Regions of Sodium 1,4-Bis(2-ethylhexyl)sulfosuccinate/Heptane/Water Reverse Micelles and Its Influence on Bimolecular Electron-Transfer Kinetics. J Phys Chem B 2007; 111:8842-53. [PMID: 17608520 DOI: 10.1021/jp0722004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Sodium 1,4-bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micellar medium has been used to study the photoinduced electron-transfer (ET) reactions between some coumarin derivatives and amines, namely, aniline (AN) and N,N-dimethylaniline (DMAN) at different w(0) (w(0) = [water]/[AOT]) values, to explore the appearance of Marcus inversion and also the possible role of w(0), if any, on the Marcus correlation curves. The coumarin derivatives are found to partition between the heptane-like and the water-like phases of the reverse micelles, and their locations have been confirmed by time-resolved anisotropy measurements. Fluorescence quenching is found to depend both on the location of the coumarin molecules and on the hydrophobicity of the amine donors. Various aspects such as the effect of differential partitioning of the quenchers, the location of the probes in the two phases, the diffusion of the reactants in the micellar phase, etc. have been considered to rationalize the fluorescence quenching rates in reverse micelles. Rotational relaxation times and the diffusion parameters estimated from the anisotropy results do not show good correlation with the observed quenching rates indicating that the diffusion of reactants has no role in the quenching kinetics in reverse micelles. Marcus inversion behavior has been observed for the coumarin-amine systems in the water-like phase at a relatively high exergonicity of approximately 1.2 eV suggesting that the solvent reorganization energy contributes fully to the free energy of activation for the ET reactions in the present systems. This is in accordance with the fast solvent relaxation dynamics reported in reverse micelles. Quenching rates in the water-like phase are found to decrease or increase marginally with increasing w(0) for the coumarin-DMAN and coumarin-AN systems, respectively. This is explained on the basis of the changing solubility of these amines in the water-like phase with changing w(0) values of the reverse micelles. In the heptane-like phase, no clear inversion in the quenching rate versus free energy plot could be observed because the study could not be extended to higher exergonicity due to nonsolubility of the dye C151 in this phase. Present results, especially in the water-like phase, suggest that the confinement of reactants in micellar media can effectively remove the influence of reactant diffusion on bimolecular ET rates and thus make the systems more conducive for the observation of the Marcus inverted region.
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Baruah B, Crans DC, Levinger NE. Simple oxovanadates as multiparameter probes of reverse micelles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:6510-8. [PMID: 17489609 DOI: 10.1021/la063072y] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Using a wide range of different methods, researchers have found that the environment inside reverse micelles differs from bulk aqueous solution in many ways. Here, we present a new tool, a series of aqueous oxovanadium(V) reactions, to probe pH, viscosity, and ionic strength in the aqueous interior of reverse micelles. In addition to their potential as anionic probe analogues to phosphates, simple oxovanadium(V) compounds have equilibrium characteristics in aqueous media exquisitely sensitive to their environment. Therefore, the speciation of vanadate equilibria can be used as a parameter to characterize the intramicellar medium. Vanadate speciation is monitored through 51V NMR spectroscopy, which also yields information through chemical shifts and linewidths of spectral features. The speciation observed suggests that the relative acidity of a basic vanadate stock solution is slightly reduced in large, w0 >or= 12, reverse micelles, but that for smaller reverse micelles, speciation reflects the strong interaction of these negatively charged oxometalates with the reverse micelle and suggest an increased solution viscosity in the reverse micelles. This interpretation is obtained through different responses closely linked to the reverse micellar size and the specific conditions in the stock solutions used to form reverse micelles.
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Affiliation(s)
- Bharat Baruah
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA
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Mondal SK, Ghosh S, Sahu K, Mandal U, Bhattacharyya K. Ultrafast fluorescence resonance energy transfer in a reverse micelle: Excitation wavelength dependence. J Chem Phys 2006; 125:224710. [PMID: 17176157 DOI: 10.1063/1.2403131] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Fluorescence resonance energy transfer (FRET) from coumarin 480 (C480) to fluorescein 548 (F548) in a sodium dioctyl sulfosuccinate (AOT) reverse micelle is studied by picosecond and femtosecond emission spectroscopy. In bulk water, at the low concentration of the donor (C480) and the acceptor (F548), no FRET is observed. However, when the donor (C480) and the acceptor (F548) are confined in a AOT reverse micelle very fast FRET is observed. The time constants of FRET were obtained from the rise time of the emission of the acceptor (F548). In a AOT microemulsion, FRET is found to occur in multiple time scales--3, 200, and 2700 ps. The 3 ps component is assigned to FRET in the water pool of the reverse micelle with a donor-acceptor distance, 16 A. The 200 ps component corresponds to a donor-acceptor distance of 30 A and is ascribed to the negatively charged acceptor inside the water pool and the neutral donor inside the alkyl chains of AOT. The very long 2700 ps component may arise due to FRET from a donor outside the micelle to an acceptor inside the water pool and also from diffusion of the donor from bulk heptane to the reverse micelle. With increase in the excitation wavelength from 375 to 405 nm the relative contribution of the FRET due to C480 in the AOT reverse micelle (the 3 and 200 ps components) increases.
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Affiliation(s)
- Sudip Kumar Mondal
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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Baruah B, Roden JM, Sedgwick M, Correa NM, Crans DC, Levinger NE. When Is Water Not Water? Exploring Water Confined in Large Reverse Micelles Using a Highly Charged Inorganic Molecular Probe. J Am Chem Soc 2006; 128:12758-65. [PMID: 17002370 DOI: 10.1021/ja0624319] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The interior water pool of aerosol OT (AOT) reverse micelles tends toward bulk water properties as the micelle size increases. Thus, deviations from bulk water behavior in large reverse micelles are less expected than in small reverse micelles. Probing the interior water pool of AOT reverse micelles with a highly charged decavanadate (V(10)) oligomer using (51)V NMR spectroscopy shows distinct changes in solute environment. For example, when an acidic stock solution of protonated V(10) is placed in a reverse micelle, the (51)V chemical shifts show that the V(10) is deprotonated consistent with a decreased proton concentration in the intramicellar water pool. Results indicate that a proton gradient exists inside the reverse micelles, leaving the interior neutral while the interfacial region is acidic.
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Affiliation(s)
- Bharat Baruah
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA
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Chakraborty A, Seth D, Setua P, Sarkar N. Dynamics of Solvent and Rotational Relaxation of Glycerol in the Nanocavity of Reverse Micelles. J Phys Chem B 2006; 110:5359-66. [PMID: 16539469 DOI: 10.1021/jp056650c] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The dynamics of solvent and rotational relaxation of Coumarin 480 and Coumarin 490 in glycerol containing bis-2-ethyl hexyl sulfosuccinate sodium salt (AOT) reverse micelles have been investigated with steady-state and time-resolved fluorescence spectroscopy. We observed slower solvent relaxation of glycerol confined in the nanocavity of AOT reverse micelles compared to that in pure glycerol. However, the slowing down in the solvation time on going from neat glycerol to glycerol confined reverse micelles is not comparable to that on going from pure water or acetonitrile to water or acetonitrile confined AOT reverse micellar aggregates. While solvent relaxation times were found to decrease with increasing glycerol content in the reverse micellar pool, rotational relaxation times were found to increase with increase in glycerol content.
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Affiliation(s)
- Anjan Chakraborty
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
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Chakraborty A, Seth D, Setua P, Sarkar N. Photoinduced electron transfer from N,N-dimethylaniline to 7-amino Coumarins in protein-surfactant complex: Slowing down of electron transfer dynamics compared to micelles. J Chem Phys 2006; 124:74512. [PMID: 16497062 DOI: 10.1063/1.2170081] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Photoinduced electron transfer from N,N-dimethylaniline to different Coumarin dyes has been investigated in dodecyl trimethyl ammonium bromide (DTAB) micelles and in Bovine serum albumin (BSA)-DTAB protein-surfactant complex using steady-state and picosecond time-resolved fluorescence spectroscopy. We observed a slower fluorescence quenching rate in the DTAB micelles and in the protein-surfactant complex as compared to that in pure acetonitrile solution. Moreover, the observed fluorescence quenching in BSA-DTAB complex was found to be slower than that in DTAB micelles. In the correlation of free-energy change with the fluorescence quenching constant we observed a deviation in the fluorescence quenching electron transfer rate for Coumarin 151 (C-151) from the normal Marcus curve. This observation is ascribed to the stronger interaction of C-151 with the surfactant molecules present in the micelles. This is evident from the slower translation diffusion (D(L)) of Coumarin 151 compared to other probe molecules.
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Affiliation(s)
- Anjan Chakraborty
- Department of Chemistry, Indian Institute of Technology, Kharagpur, West Bengal
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