1
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Baldo AP, Ilgen AG, Leung K. Deprotonation of formic, acetic acids and bicarbonate ion in slit silica nanopores at infinite dilution and in the presence of electrolytes. J Colloid Interface Sci 2024; 674:482-489. [PMID: 38941940 DOI: 10.1016/j.jcis.2024.05.160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/09/2024] [Accepted: 05/21/2024] [Indexed: 06/30/2024]
Abstract
Dielectric effects and the coupled electrostatics between the nanoconfined and the internal/external aqueous media contribute to the observed deviations of chemistry within the nanoconfined environment when compared with unconfined systems. A systematic understanding has remained elusive, especially with respect to background salt concentration and boundary condition effects like the nanopore surface chemistry and the reference state used to calculate free energies. We utilize molecular dynamics simulations along with thermodynamic integration to determine the free energy difference associated with acid-base chemistry in 2 nm and 4 nm slit pores open to a bulk-like reservoir. pKa increases are predicted when confining acetic acid, formic acid, and bicarbonate in the slits at infinite dilution conditions. We find that confinement weakens the acids, and the modulation of outer pore surface dipole magnitudes can tune the pKa shift values, suggesting that purely "intrinsic" electrostatic effect on confinement may not exist. At sufficiently high salt concentrations, the dielectric/electrostatic effects on pKa values diminish due to charge screening effects. These discoveries enable future modifications of nanopore chemistries to achieve desirable properties for industrial applications.
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Affiliation(s)
- Anthony P Baldo
- Geochemistry Department, Sandia National Laboratories, Albuquerque, NM 87123, USA.
| | - Anastasia G Ilgen
- Geochemistry Department, Sandia National Laboratories, Albuquerque, NM 87123, USA
| | - Kevin Leung
- Geochemistry Department, Sandia National Laboratories, Albuquerque, NM 87123, USA
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2
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Olivieri JF, Laage D, Hynes JT. A Model Electron Transfer Reaction in Confined Aqueous Solution. Chemphyschem 2021; 22:2247-2255. [PMID: 34427964 DOI: 10.1002/cphc.202100351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 08/24/2021] [Indexed: 11/09/2022]
Abstract
Liquid water confined within nanometer-sized channels exhibits a strongly reduced local dielectric constant perpendicular to the wall, especially at the interface, and this has been suggested to induce faster electron transfer kinetics at the interface than in the bulk. We study a model electron transfer reaction in aqueous solution confined between graphene sheets with classical molecular dynamics. We show that the solvent reorganization energy is reduced at the interface compared to the bulk, which explains the larger rate constant. However, this facilitated solvent reorganization is due to the partial desolvation by the graphene sheet of the ions involved in the electron transfer and not to a local dielectric constant reduction effect.
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Affiliation(s)
- Jean-François Olivieri
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
| | - Damien Laage
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
| | - James T Hynes
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France.,Department of Chemistry, University of Colorado, Boulder, CO 80309, USA
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3
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Affiliation(s)
- Ward H. Thompson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA
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4
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Harvey JA, Thompson WH. Solute location in a nanoconfined liquid depends on charge distribution. J Chem Phys 2015; 143:044701. [DOI: 10.1063/1.4926936] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jacob A. Harvey
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA
| | - Ward H. Thompson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA
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5
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Harvey JA, Thompson WH. Thermodynamic Driving Forces for Dye Molecule Position and Orientation in Nanoconfined Solvents. J Phys Chem B 2014; 119:9150-9. [DOI: 10.1021/jp509051n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jacob A. Harvey
- Department
of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Ward H. Thompson
- Department
of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
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6
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Tomkins J, Hanna G. Signatures of nanoconfinement on the linear and nonlinear vibrational spectroscopy of a model hydrogen-bonded complex dissolved in a polar solvent. J Phys Chem B 2013; 117:13619-30. [PMID: 24079369 DOI: 10.1021/jp407469f] [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
The one-dimensional IR (1D-IR) absorption and IR pump-probe spectra of a hydrogen stretch in a model hydrogen-bonded complex dissolved in a polar solvent confined in spherical hydrophobic cavities of different sizes were simulated using ground-state mixed quantum-classical dynamics. Due to a thorough analysis of key properties of the complex and solvent from equilibrium trajectory data, we were able to gain insight into the microscopic details underlying the spectra. Both the 1D-IR and IR pump-probe spectra manifested the effects of confinement on the relative stabilities of the covalent and ionic forms of the complex through pronounced changes in their peak intensities and numbers. However, in contrast to the 1D-IR spectra, the time-resolved pump-probe spectra were found to be uniquely sensitive to the changes in the molecular dynamics as the cavity size is varied. In particular, it was found that the variations in the time evolutions of the peak intensities in the pump-probe spectra reflect the differences in the solvation dynamics associated with the various forms of the complex in different locations within the cavities. The ability to detect these differences underscores the advantage of using pump-probe spectroscopy for studying nanoconfined systems.
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Affiliation(s)
- Joseph Tomkins
- Department of Chemistry, University of Alberta , Edmonton, Alberta, Canada T6G 2G2
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7
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Das A, Chakrabarti J. Microscopic Mechanisms of Confinement-Induced Slow Solvation. J Phys Chem A 2013; 117:10571-5. [DOI: 10.1021/jp405680j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Amit Das
- Department
of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India
| | - J. Chakrabarti
- Department
of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India
- Unit
of Nanoscience and Technology-II, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India
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8
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Wohnhaas C, Mailänder V, Dröge M, Filatov MA, Busko D, Avlasevich Y, Baluschev S, Miteva T, Landfester K, Turshatov A. Triplet-Triplet Annihilation Upconversion Based Nanocapsules for Bioimaging Under Excitation by Red and Deep-Red Light. Macromol Biosci 2013; 13:1422-30. [DOI: 10.1002/mabi.201300149] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 06/06/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Christian Wohnhaas
- Max Planck Institute for Polymer Research, Ackermannweg 10; 55128 Mainz Germany
| | - Volker Mailänder
- Max Planck Institute for Polymer Research, Ackermannweg 10; 55128 Mainz Germany
- Third Department of Medicine; University Medicine of the Johannes Gutenberg University, Langenbeckstr. 1; 55131 Mainz Germany
| | - Melanie Dröge
- Max Planck Institute for Polymer Research, Ackermannweg 10; 55128 Mainz Germany
| | - Mikhail A. Filatov
- Max Planck Institute for Polymer Research, Ackermannweg 10; 55128 Mainz Germany
| | - Dmitry Busko
- Max Planck Institute for Polymer Research, Ackermannweg 10; 55128 Mainz Germany
| | - Yuri Avlasevich
- Max Planck Institute for Polymer Research, Ackermannweg 10; 55128 Mainz Germany
| | - Stanislav Baluschev
- Max Planck Institute for Polymer Research, Ackermannweg 10; 55128 Mainz Germany
- Optics and Spectroscopy Department; Faculty of Physics, Sofia University “St. Kliment Ochridski,” James Bourchier 5; 1164 Sofia Bulgaria
| | - Tzenka Miteva
- Materials Science Laboratory, Sony Deutschland GmbH, Hedelfingerstr. 61; 70327 Stuttgart Germany
| | | | - Andrey Turshatov
- Max Planck Institute for Polymer Research, Ackermannweg 10; 55128 Mainz Germany
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9
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Guchhait B, Biswas R, Ghorai PK. Solute and Solvent Dynamics in Confined Equal-Sized Aqueous Environments of Charged and Neutral Reverse Micelles: A Combined Dynamic Fluorescence and All-Atom Molecular Dynamics Simulation Study. J Phys Chem B 2013; 117:3345-61. [DOI: 10.1021/jp310285k] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Biswajit Guchhait
- Department
of Chemical, Biological and
Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt
Lake, Kolkata 700098, India
| | - Ranjit Biswas
- Department
of Chemical, Biological and
Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt
Lake, Kolkata 700098, India
| | - Pradip K. Ghorai
- Indian Institute of Science Education and Research, Kolkata, Mohanpur Campus, Nadia 741252,
India
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Chowdhury R, Mojumdar SS, Chattoraj S, Bhattacharyya K. Effect of ionic liquid on the native and denatured state of a protein covalently attached to a probe: Solvation dynamics study. J Chem Phys 2012; 137:055104. [DOI: 10.1063/1.4739922] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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11
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Vartia AA, Thompson WH. Solvation and Spectra of a Charge Transfer Solute in Ethanol Confined within Nanoscale Silica Pores. J Phys Chem B 2012; 116:5414-24. [DOI: 10.1021/jp210737c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anthony A. Vartia
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Ward H. Thompson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
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12
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Chowdhury A, Mojumdar SS, Choudhury A, Banerjee R, Das KP, Sasmal DK, Bhattacharyya K. Deoxycholate induced tetramer of αA-crystallin and sites of phosphorylation: Fluorescence correlation spectroscopy and femtosecond solvation dynamics. J Chem Phys 2012; 136:155101. [DOI: 10.1063/1.3702810] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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13
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Elola MD, Rodriguez J, Laria D. Liquid Methanol Confined within Functionalized Silica Nanopores. 2. Solvation Dynamics of Coumarin 153. J Phys Chem B 2011; 115:12859-67. [DOI: 10.1021/jp205832y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. Dolores Elola
- Departamento de Física, Comisión Nacional de Energía Atómica, Avenida Libertador 8250, 1429 Buenos Aires, Argentina
| | - Javier Rodriguez
- Departamento de Física, Comisión Nacional de Energía Atómica, Avenida Libertador 8250, 1429 Buenos Aires, Argentina
- ECyT, UNSAM, Martín de Irigoyen 3100, 1650 San Martín, Provincia de Buenos Aires, Argentina
| | - Daniel Laria
- Departamento de Física, Comisión Nacional de Energía Atómica, Avenida Libertador 8250, 1429 Buenos Aires, Argentina
- Departamento de Qumica Inorgánica Analítica y Química-Física e INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II. 1428 Buenos Aires, Argentina
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14
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Ghatak C, Rao VG, Ghosh S, Mandal S, Sarkar N. Solvation Dynamics and Rotational Relaxation Study Inside Niosome, A Nonionic Innocuous Poly(ethylene Glycol)-Based Surfactant Assembly: An Excitation Wavelength Dependent Experiment. J Phys Chem B 2011; 115:12514-20. [DOI: 10.1021/jp204473d] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Chiranjib Ghatak
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
| | - Vishal Govind Rao
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
| | - Shirsendu Ghosh
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
| | - Sarthak Mandal
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
| | - Nilmoni Sarkar
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
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15
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Laird BB, Thompson WH. Time-dependent fluorescence in nanoconfined solvents: Linear-response approximations and Gaussian statistics. J Chem Phys 2011; 135:084511. [DOI: 10.1063/1.3626825] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Abstract
Nanoconfined liquids are of interest because of both their fundamental properties and their potential utility in an array of applications. The structure and dynamics of the liquid can be dramatically impacted by the geometrical constraints and the interactions with the interface. Understanding the molecular-level origins of these changes and how they are determined by the characteristics of the confining framework is the subject of ongoing experimental and theoretical studies. The progress and remaining challenges in these efforts are reviewed in the context of solvation dynamics and proton transfer reactions, processes that are strongly affected by nanoscale confinement.
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Affiliation(s)
- Ward H Thompson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA.
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17
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Chowdhary J, Ladanyi BM. Molecular simulation study of water mobility in aerosol-OT reverse micelles. J Phys Chem A 2011; 115:6306-16. [PMID: 21548627 DOI: 10.1021/jp201866t] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In this work, we present results from molecular dynamics simulations on the single-molecule relaxation of water within reverse micelles (RMs) of different sizes formed by the surfactant aerosol-OT (AOT, sodium bis(2-ethylhexyl)sulfosuccinate) in isooctane. Results are presented for RM water content w(0) = [H(2)O]/[AOT] in the range from 2.0 to 7.5. We show that translational diffusion of water within the RM can, to a good approximation, be decoupled from the translation of the RM through the isooctane solvent. Water translational mobility within the RM is restricted by the water pool dimensions, and thus, the water mean-squared displacements (MSDs) level off in time. Comparison with models of diffusion in confined geometries shows that a version of the Gaussian confinement model with a biexponential decay of correlations provides a good fit to the MSDs, while a model of free diffusion within a sphere agrees less well with simulation results. We find that the local diffusivity is considerably reduced in the interfacial region, especially as w(0) decreases. Molecular orientational relaxation is monitored by examining the behavior of OH and dipole vectors. For both vectors, orientational relaxation slows down close to the interface and as w(0) decreases. For the OH vector, reorientation is strongly affected by the presence of charged species at the RM interface and these effects are especially pronounced for water molecules hydrogen-bonded to surfactant sites that serve as hydrogen-bond acceptors. For the dipole vector, orientational relaxation near the interface slows down more than that for the OH vector due mainly to the influence of ion-dipole interactions with the sodium counterions. We investigate water OH and dipole reorientation mechanisms by studying the w(0) and interfacial shell dependence of orientational time correlations for different Legendre polynomial orders.
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Affiliation(s)
- Janamejaya Chowdhary
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA
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18
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Gulmen TS, Thompson W. Model silica pores with controllable surface chemistry for molecular dynamics simulatinos. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-0899-n06-05] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractModel amorphous silica pores have been developed for use in molecular dynamics simulations. Specifically, roughly cylindrical pores have been constructed with hydrophilic, hydroxyl-terminated surfaces. The approach is designed to allow systematic variation of the pore radius and surface functionality. Thus, these pores are suitable for studying the variability in solvent structure, energy transfer and reaction dynamics occurring inside the pore due to surface modification. The method is described and the properties of the generated pores are discussed.
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19
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Sasmal DK, Mojumdar SS, Adhikari A, Bhattacharyya K. Deuterium Isotope Effect on Femtosecond Solvation Dynamics in an Ionic Liquid Microemulsion: An Excitation Wavelength Dependence Study. J Phys Chem B 2010; 114:4565-71. [DOI: 10.1021/jp910948w] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Dibyendu Kumar Sasmal
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Supratik Sen Mojumdar
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Aniruddha Adhikari
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Kankan Bhattacharyya
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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20
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Sasmal DK, Dey S, Das DK, Bhattacharyya K. Deuterium isotope effect on femtosecond solvation dynamics in methyl β-cyclodextrins. J Chem Phys 2009; 131:044509. [DOI: 10.1063/1.3176020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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21
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Furse KE, Corcelli SA. Effects of Long-Range Electrostatics on Time-Dependent Stokes Shift Calculations. J Chem Theory Comput 2009; 5:1959-67. [DOI: 10.1021/ct9001416] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kristina E. Furse
- Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556
| | - Steven A. Corcelli
- Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556
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22
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Bratko D, Daub CD, Luzar A. Water-mediated ordering of nanoparticles in an electric field. Faraday Discuss 2009; 141:55-66; discussion 81-98. [PMID: 19227351 DOI: 10.1039/b809135h] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Interfacial polar molecules feature a strongly anisotropic response to applied electric field, favoring dipole orientations parallel to the interface. In water, in particular, this effect combines with generic orientational preferences induced by spatial asymmetry of water hydrogen bonding under confined geometry, which may give rise to a Janus interface. The two effects manifest themselves in considerable dependence of water polarization on both the field direction relative to the interface and the polarity (sign) of the field. Using molecular simulations, we demonstrate strong field-induced orientational forces acting on apolar surfaces through water mediation. At a field strength comparable to electric fields around a DNA polyion, the torques we predict to act on an adjacent nanoparticle are sufficient to overcome thermal fluctuations. These torques can align a particle with surface as small as 1 nm2. The mechanism can support electrically controlled ordering of suspended nanoparticles as a means of tuning their properties and can find application in electro-nanomechanical devices.
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Affiliation(s)
- Dusan Bratko
- Department of Chemistry, Virginia Commonwealth University, Richmond, VA 23284-2006, USA.
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23
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Morales CM, Thompson WH. Simulations of Infrared Spectra of Nanoconfined Liquids: Acetonitrile Confined in Nanoscale, Hydrophilic Silica Pores. J Phys Chem A 2008; 113:1922-33. [DOI: 10.1021/jp8072969] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | - Ward H. Thompson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045
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24
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Dey S, Sasmal DK, Das DK, Bhattacharyya K. A Femtosecond Study of Solvation Dynamics and Anisotropy Decay in a Catanionic Vesicle: Excitation-Wavelength Dependence. Chemphyschem 2008; 9:2848-55. [DOI: 10.1002/cphc.200800658] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Mandal U, Ghosh S, Mitra G, Adhikari A, Dey S, Bhattacharyya K. A Femtosecond Study of the Interaction of Human Serum Albumin with a Surfactant (SDS). Chem Asian J 2008; 3:1430-4. [DOI: 10.1002/asia.200800114] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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26
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Rodriguez J, Martí J, Guàrdia E, Laria D. Exploring the Picosecond Time Domain of the Solvation Dynamics of Coumarin 153 within β-Cyclodextrins. J Phys Chem B 2008; 112:8990-8. [DOI: 10.1021/jp8023765] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Javier Rodriguez
- Departamento de Física, Comisión Nacional de Energia Atómica, Avenida Libertador 8250, 1429, Buenos Aires, Argentina, Departamento de Química Inorgánica, Analítica y Química-Física e INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, 1428, Buenos Aires, Argentina, and Departament de Fısica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, B4-B5 Campus Nord 08034, Barcelona, Spain
| | - Jordi Martí
- Departamento de Física, Comisión Nacional de Energia Atómica, Avenida Libertador 8250, 1429, Buenos Aires, Argentina, Departamento de Química Inorgánica, Analítica y Química-Física e INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, 1428, Buenos Aires, Argentina, and Departament de Fısica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, B4-B5 Campus Nord 08034, Barcelona, Spain
| | - Elvira Guàrdia
- Departamento de Física, Comisión Nacional de Energia Atómica, Avenida Libertador 8250, 1429, Buenos Aires, Argentina, Departamento de Química Inorgánica, Analítica y Química-Física e INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, 1428, Buenos Aires, Argentina, and Departament de Fısica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, B4-B5 Campus Nord 08034, Barcelona, Spain
| | - Daniel Laria
- Departamento de Física, Comisión Nacional de Energia Atómica, Avenida Libertador 8250, 1429, Buenos Aires, Argentina, Departamento de Química Inorgánica, Analítica y Química-Física e INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, 1428, Buenos Aires, Argentina, and Departament de Fısica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, B4-B5 Campus Nord 08034, Barcelona, Spain
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27
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Adhikari A, Dey S, Das DK, Mandal U, Ghosh S, Bhattacharyya K. Solvation Dynamics in Ionic Liquid Swollen P123 Triblock Copolymer Micelle: A Femtosecond Excitation Wavelength Dependence Study. J Phys Chem B 2008; 112:6350-7. [DOI: 10.1021/jp7118857] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Aniruddha Adhikari
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Shantanu Dey
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Dibyendu Kumar Das
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Ujjwal Mandal
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Subhadip Ghosh
- 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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Dey S, Adhikari A, Mandal U, Ghosh S, Bhattacharyya K. A Femtosecond Study of Excitation Wavelength Dependence of a Triblock Copolymer−Surfactant Supramolecular Assembly: (PEO)20−(PPO)70−(PEO)20 and CTAC. J Phys Chem B 2008; 112:5020-6. [DOI: 10.1021/jp8002257] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Shantanu Dey
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Aniruddha Adhikari
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Ujjwal Mandal
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Subhadip Ghosh
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Kankan Bhattacharyya
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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29
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Adhikari A, Sahu K, Dey S, Ghosh S, Mandal U, Bhattacharyya K. Femtosecond Solvation Dynamics in a Neat Ionic Liquid and Ionic Liquid Microemulsion: Excitation Wavelength Dependence. J Phys Chem B 2007; 111:12809-16. [DOI: 10.1021/jp075693l] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Aniruddha Adhikari
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Kalyanasis Sahu
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Shantanu Dey
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Subhadip Ghosh
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Ujjwal Mandal
- 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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31
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Seth D, Chakraborty A, Setua P, Sarkar N. Interaction of ionic liquid with water with variation of water content in 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6])/TX-100/water ternary microemulsions monitored by solvent and rotational relaxation of coumarin 153 and coumarin 490. J Chem Phys 2007; 126:224512. [PMID: 17581068 DOI: 10.1063/1.2736378] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The interaction of water with room temperature ionic liquid (RTIL) [bmim][PF6] has been studied in [bmim][PF6]/TX-100/water ternary microemulsions by solvent and rotational relaxation of coumarin 153 (C-153) and coumarin 490 (C-490). The rotational relaxation and average solvation time of C-153 and C-490 gradually decrease with increase in water content of the microemulsions. The gradual increase in the size of the microemulsion with increase in w0 (w0=[water]/[surfactant]) is evident from dynamic light scattering measurements. Consequently the mobility of the water molecules also increases. In comparison to pure water the retardation of solvation time in the RTIL containing ternary microemulsions is very less. The authors have also reported the solvation time of C-490 in neat [bmim][PF6]. The solvation time of C-490 in neat [bmim][PF6] is bimodal with time constants of 400 ps and 1.10 ns.
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Affiliation(s)
- Debabrata Seth
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, West Bengal, India
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32
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Ghosh S, Mandal U, Adhikari A, Dey S, Bhattacharyya K. Study of organized and biological systems using an ultrafast laser. INT REV PHYS CHEM 2007. [DOI: 10.1080/01442350701416888] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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33
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Laird BB, Thompson WH. On the connection between Gaussian statistics and excited-state linear response for time-dependent fluorescence. J Chem Phys 2007; 126:211104. [PMID: 17567183 DOI: 10.1063/1.2747237] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Time-dependent fluorescence (TDF) of a chromophore in a polar or nonpolar solvent is frequently simulated using linear-response approximations. It is shown that one such linear-response-type approximation for the TDF Stokes shift derived by Carter and Hynes [J. Chem. Phys. 94, 5961 (1991)] that is based on excited-state dynamics gives the same result as that obtained by assuming Gaussian statistics for the energy gap. The derivation provides insight into the much discussed relationship between linear response and Gaussian statistics. In particular, subtle but important differences between the two approximations are illuminated that suggest that the result is likely more generally applicable than suggested by the usual linearization procedure. In addition, the assumption of Gaussian statistics directly points to straightforward checks of the validity of the approximation with essentially no additional computational effort.
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Affiliation(s)
- Brian B Laird
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA.
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34
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Mandal U, Adhikari A, Dey S, Ghosh S, Mondal SK, Bhattacharyya K. Excitation Wavelength Dependence of Solvation Dynamics in a Supramolecular Assembly: PEO−PPO−PEO Triblock Copolymer and SDS. J Phys Chem B 2007; 111:5896-902. [PMID: 17477559 DOI: 10.1021/jp0689722] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The triblock copolymer (PEO)20-(PPO)70-(PEO)20 (P123) forms a supramolecular aggregate with sodium dodecyl sulfate (SDS). The solvation dynamics and anisotropy decay of coumarin 480 (C480) in different regions of a P123-SDS aggregate are studied through variation of the excitation wavelength (lambdaex) using femtosecond upconversion. In a P123 micelle, because of the drastic differences in polarity between the hydrophilic corona region (PEO block) and the hydrophobic PPO core, C480 exhibits a pronounced red edge excitation shift (REES) of emission maximum by 24 nm. In the P123-SDS aggregate, SDS penetrates the core of the P123 micelle. This increases the polarity of the core and reduces the difference in the polarity between the core and the corona region. In a P123-SDS aggregate, the REES is much smaller (5 nm) which suggests a reduced difference between the core and the corona. Solvation dynamics in a P123 micelle displays a bulklike ultrafast component (<0.3 and 1 ps) in the PEO corona region, a 200 ps component arising from dynamics of polymer segments, and a very long component (5000 or 3000 ps) due to the highly restricted PPO core. In a P123-SDS aggregate, at lambdaex = 375 and 405 nm, the solvation dynamics is found to be faster than that in P123 micelle. In this case, the component (3000 ps) arising from the core region is faster than that (5000 ps) in P123 micelle. In both P123 micelle and P123-SDS aggregate, the relative contribution of the core region decreases and that of the corona region increases with an increase in lambdaex. At lambdaex = 435 nm, which probes the hydrophilic corona, the solvation dynamics for both P123 micelle and P123-SDS aggregate are almost similar.
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Affiliation(s)
- Ujjwal Mandal
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, India
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35
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Ghosh S, Mondal SK, Sahu K, Bhattacharyya K. Ultrafast Electron Transfer in a Nanocavity. Dimethylaniline to Coumarin Dyes in Hydroxypropyl γ-Cyclodextrin. J Phys Chem A 2006; 110:13139-44. [PMID: 17149826 DOI: 10.1021/jp064412r] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Photoinduced electron transfer (PET) from N,N-dimethylaniline (DMA) to four coumarin dyes (C151, C481, C153, and C480) inside the cavity of hydroxypropyl gamma-cyclodextrin (hpCD) is studied using femtosecond upconversion. The rate of PET is found to be nonexponential and to vary significantly with the coumarin dyes. The rate for C481 is 100 times faster than that for C480. The PET rate displays a bell-shaped dependence on the free energy change and thus reveals a Marcus-type inverted region. The anisotropy decay of the four dyes in hpCD are found to be very similar, and hence the observed variation in the rate of PET is not due to variation in rotational diffusion of the acceptors (coumarin dyes).
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Affiliation(s)
- Subhadip Ghosh
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata - 700 032, India
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36
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Portuondo-Campa E, Tortschanoff A, van Mourik F, Moser JE, Kornherr A, Chergui M. Aqueous Solvation Dynamics at Metal Oxide Surfaces. J Phys Chem B 2006; 110:7835-44. [PMID: 16610880 DOI: 10.1021/jp056442k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Broadband transient absorption (TA) spectroscopy, three-pulse photon echo peak shift (3PEPS), and anisotropy decay measurements were used to study the solvation dynamics in bulk water and interfacial water at ZrO(2) surfaces, using Eosin Y as a probe. The 3PEPS results show a multiexponential behavior with two subpicosecond components that are similar in bulk and interfacial water, while a third component of several picoseconds is significantly lengthened at the interface. The bandwidth correlation function from TA spectra exhibits the same behavior, and the TA spectra are well reproduced using the doorway-window picture with the time constants from PEPS. Our results suggest that interfacial water is restricted to a thickness of less than 5 A. Also the high-frequency collective dynamics of water does not seem to be affected by the interface. On the other hand, the increase of the third component may point to a slowing down of diffusional motion at the interface, although other effects, may play a role, which are discussed.
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Affiliation(s)
- Erwin Portuondo-Campa
- Laboratoire de Spectroscopie Ultrarapide, ISIC, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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37
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Piletic IR, Moilanen DE, Spry DB, Levinger NE, Fayer MD. Testing the Core/Shell Model of Nanoconfined Water in Reverse Micelles Using Linear and Nonlinear IR Spectroscopy. J Phys Chem A 2006; 110:4985-99. [PMID: 16610816 DOI: 10.1021/jp061065c] [Citation(s) in RCA: 269] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A core/shell model has often been used to describe water confined to the interior of reverse micelles. The validity of this model for water encapsulated in AOT/isooctane reverse micelles ranging in diameter from 1.7 to 28 nm (w0 = 2-60) and bulk water is investigated using four experimental observables: the hydroxyl stretch absorption spectra, vibrational population relaxation times, orientational relaxation rates, and spectral diffusion dynamics. The time dependent observables are measured with ultrafast infrared spectrally resolved pump-probe and vibrational echo spectroscopies. Major progressive changes appear in all observables as the system moves from bulk water to the smallest water nanopool, w0 = 2. The dynamics are readily distinguishable for reverse micelle sizes smaller than 7 nm in diameter (w0 = 20) compared to the response of bulk water. The results also demonstrate that the size dependent absorption spectra and population relaxation times can be quantitatively predicted using a core-shell model in which the properties of the core (interior of the nanopool) are taken to be those of bulk water and the properties of the shell (water associated with the headgroups) are taken to be those of w0 = 2. A weighted sum of the core and shell components reproduces the size dependent spectra and the nonexponential population relaxation dynamics. However, the same model does not reproduce the spectral diffusion and the orientational relaxation experiments. It is proposed that, when hydrogen bond structural rearrangement is involved (orientational relaxation and spectral diffusion), dynamical coupling between the shell and the core cause the water nanopool to display more homogeneous dynamics. Therefore, the absorption spectra and vibrational lifetime decays can discern different hydrogen bonding environments whereas orientational and spectral diffusion correlation functions predict that the dynamics are size dependent but not as strongly spatially dependent within a reverse micelle.
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Affiliation(s)
- Ivan R Piletic
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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38
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Sahu K, Mondal SK, Ghosh S, Roy D, Bhattacharyya K. Temperature dependence of solvation dynamics and anisotropy decay in a protein: ANS in bovine serum albumin. J Chem Phys 2006; 124:124909. [PMID: 16599727 DOI: 10.1063/1.2178782] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Temperature dependence of solvation dynamics and fluorescence anisotropy decay of 8-anilino-1-naphthalenesulfonate (ANS) bound to a protein, bovine serum albumin (BSA), are studied. Solvation dynamics of ANS bound to BSA displays a component (300 ps) which is independent of temperature in the range of 278-318 K and a long component which decreases from 5800 ps at 278 K to 3600 ps at 318 K. The temperature independent part is ascribed to a dynamic exchange of bound to free water with a low barrier. The temperature variation of the long component of solvation dynamics corresponds to an activation energy of 2.1 kcal mol(-1). The activation energy is ascribed to local segmental motion of the protein along with the associated water molecules and polar residues. The time scale of solvation dynamics is found to be very different from the time scale of anisotropy decay. The anisotropy decays are analyzed in terms of the wobbling motion of the probe (ANS) and the overall tumbling of the protein.
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Affiliation(s)
- Kalyanasis Sahu
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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39
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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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40
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Sahu K, Mondal SK, Ghosh S, Roy D, Sen P, Bhattacharyya K. Femtosecond Study of Partially Folded States of Cytochrome C by Solvation Dynamics. J Phys Chem B 2005; 110:1056-62. [PMID: 16471642 DOI: 10.1021/jp0538924] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Using femtosecond time-resolved fluorescence spectroscopy, it is shown that the solvation dynamics in the two partially folded states (IS' and IS' ') of a protein, cytochrome C, are very different. In the case of IS' (formed by the addition of 2 mM sodium dodecyl sulfate, SDS) almost the entire dynamic solvent shift of coumarin 153 (C153) is captured in a picosecond setup and the contribution of the ultrafast component (0.5 ps) is very small (5%). Solvation dynamics of IS' ' (formed by 2 mM SDS and 5 M urea) displays a major component (47%) of 1.3 ps. This indicates that the structure of IS' ' is much more open and exposed compared to that of IS'. The difference in the dynamics of IS' and IS' ' is attributed to differences in their structure, particularly near the heme region, and the presence of urea in IS' '.
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Affiliation(s)
- Kalyanasis Sahu
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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41
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Sen P, Roy D, Mondal SK, Sahu K, Ghosh S, Bhattacharyya K. Fluorescence Anisotropy Decay and Solvation Dynamics in a Nanocavity: Coumarin 153 in Methyl β-Cyclodextrins. J Phys Chem A 2005; 109:9716-22. [PMID: 16833284 DOI: 10.1021/jp051607a] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Fluorescence anisotropy decay and solvation dynamics of coumarin 153 (C153) are studied in dimethyl beta-cyclodextrin (DIMEB) and trimethyl beta-cyclodextrin (TRIMEB) nanocavity in water. C153 binds to DIMEB and TRIMEB to form both 1:1 and 1:2 (C153:cyclodextrin) complexes. The anisotropy decays of C153 in DIMEB and TRIMEB are found to be biexponential. The fast component of anisotropy decay (approximately 1000 ps) is attributed to the 1:1 complex and the slower one (approximately 2500 ps) to the 1:2 complex. From the components of the anisotropy decay, the length of the 1:1 and 1:2 complexes are estimated. Solvation dynamics of C153 in DIMEB exhibits a very fast (2.4 ps) component (41%) and two slower components of 50 ps (29%) and 1450 ps (30%). Solvation dynamics in TRIMEB is described by three slow components of 10.3 ps (24%), 240 ps (45%), and 2450 ps (31%). Possible origins of the ultraslow components are discussed.
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Affiliation(s)
- Pratik Sen
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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42
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Study of interaction of a cationic protein with a cationic surfactant using solvation dynamics. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.08.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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43
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Roy D, Mondal SK, Sahu K, Ghosh S, Sen P, Bhattacharyya K. Temperature Dependence of Anisotropy Decay and Solvation Dynamics of Coumarin 153 in γ-Cyclodextrin Aggregates. J Phys Chem A 2005; 109:7359-64. [PMID: 16834102 DOI: 10.1021/jp0520143] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Effect of temperature on the fluorescence anisotropy decay and the ultraslow component of solvation dynamics of coumarin 153 (C153) in a gamma-cyclodextrin (gamma-CD) nanocavity are studied using a picosecond set up. The steady-state anisotropy (0.13 +/- 0.01) and residual anisotropy (0.14 +/- 0.01) in fluorescence anisotropy decay in an aqueous solution containing 7 microM C153 and 40 mM gamma-CD are found to be quite large. This indicates formation of large linear nanotube aggregates of gamma-CD linked by C153. It is estimated that >53 gamma-CD units are present in each aggregate. In these aggregates with rise in temperature, the average solvation time (<tau(s)>(obs)) decreases markedly from 680 ps at 278 K to 160 ps at 318 K. The dynamic Stokes shift is found to decrease from 800 cm(-1) at 278 K to 250 cm(-1) at 318 K. The fraction of dynamic Stokes shift (f(d)) detected in a picosecond set up is calculated using the Fee-Maroncelli procedure. The corrected solvation time (<tau(s)>(corr) = f(d)<(tau(s)>(obs)) displays an Arrhenius type temperature dependence. From the temperature variation, the activation energy and entropy of the solvation process are determined to be 12.5 kcal M(-1) and 28 cal M(-1) K(-1), respectively. The ultraslow component and its temperature dependence are ascribed to a dynamic exchange between bound and free water molecules.
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Affiliation(s)
- Durba Roy
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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44
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Faeder J, Ladanyi BM. Solvation Dynamics in Reverse Micelles: The Role of Headgroup−Solute Interactions. J Phys Chem B 2005; 109:6732-40. [PMID: 16851757 DOI: 10.1021/jp045202m] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We present molecular dynamics simulation results for solvation dynamics in the water pool of anionic-surfactant reverse micelles (RMs) of varying water content, w(0). The model RMs are designed to represent water/aerosol-OT/oil systems, where aerosol-OT is the common name for sodium bis(2-ethylhexyl)sulfosuccinate. To determine the effects of chromophore-headgroup interactions on solvation dynamics, we compare the results for charge localization in model ionic diatomic chromophores that differ only in charge sign. Electronic excitation in both cases is modeled as charge localization on one of the solute sites. We find dramatic differences in the solvation responses for anionic and cationic chromophores. Solvation dynamics for the cationic chromophore are considerably slower and more strongly w(0)-dependent than those for the anionic chromophore. Further analysis indicates that the difference in the responses can be ascribed in part to the different initial locations of the two chromophores relative to the surfactant interface. In addition, slow motion of the cationic chromophore relative to the interface is the main contributor to the longer-time decay of the solvation response to charge localization in this case.
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Affiliation(s)
- James Faeder
- Theoretical Biology and Biophysics Group, MS K710, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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45
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Martins LR, Skaf MS, Ladanyi BM. Solvation Dynamics at the Water/Zirconia Interface: Molecular Dynamics Simulations. J Phys Chem B 2004. [DOI: 10.1021/jp0470896] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lucimara R. Martins
- Instituto de Química, Universidade Estadual de Campinas, Cx. P. 6154, Campinas-SP 13083-970, Brazil
| | - Munir S. Skaf
- Instituto de Química, Universidade Estadual de Campinas, Cx. P. 6154, Campinas-SP 13083-970, Brazil
| | - Branka M. Ladanyi
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523
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