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Mondal S, Bagchi B. Ion diffusion captures composition-dependent anomalies in water-DMSO binary mixtures. J Chem Phys 2024; 160:114505. [PMID: 38506289 DOI: 10.1063/5.0189259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 03/01/2024] [Indexed: 03/21/2024] Open
Abstract
Aqueous dimethyl sulfoxide (Aq-DMSO) binary mixture exhibits many fascinating composition-dependent anomalies that are explained by using the peculiarities of the water-DMSO hydrogen bond. Ions can couple strongly to these composition-dependent anomalies to produce exotic dynamics of their own. We carry out theoretical studies using computer simulations to understand the structural and dynamical aspects of rigid monovalent cations (Li+, Na+, K+, Rb+, and Cs+) in aqueous DMSO solutions, with chloride as the counterion. We uncover a number of composition-dependent ion diffusion anomalies, which can be traced back to the interplay between the size-dependent charge density of the ion and the resulting difference in interactions of the ion with water and DMSO molecules. Size and composition dependence of the diffusion coefficients of the five ions exhibit fascinating variations that can be explained partially.
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Affiliation(s)
- Sangita Mondal
- SSCU, Indian Institute of Science, Bangalore 560012, India
| | - Biman Bagchi
- SSCU, Indian Institute of Science, Bangalore 560012, India
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Hydrogen bonding structure and dynamics of cis- and trans- conformers of N-methylformamide in water, DMSO and water-DMSO mixtures at varying compositions. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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3
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Dueby S, Dubey V, Indra S, Daschakraborty S. Non-monotonic composition dependence of the breakdown of Stokes-Einstein relation for water in aqueous solutions of ethanol and 1-propanol: explanation using translational jump-diffusion approach. Phys Chem Chem Phys 2022; 24:18738-18750. [PMID: 35900000 DOI: 10.1039/d2cp02664c] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of experimental and simulation studies examined the validity of the Stokes-Einstein relationship (SER) of water in binary water/alcohol mixtures of different mixture compositions. These studies revealed a strong non-monotonic composition dependence of the SER with maxima at the specific alcohol mole fraction where the non-idealities of the thermodynamic and transport properties are observed. The translational jump-diffusion (TJD) approach elucidated the breakdown of the SER in pure supercooled water as caused by the jump translation of molecules. The breakdown of SER in the supercooled water/methanol binary mixture was successfully explained using the same TJD approach. To further generalize the picture, here we focus on the non-monotonic composition dependence of SER breakdown of water in two water/alcohol mixtures (water/ethanol and water/propanol) for a broad temperature range. In agreement with previous studies, maximum breakdown of SER is observed for the mixture with alcohol mole fraction x = 0.2. Diffusion of the water molecules at the maximum SER breakdown point is largely contributed by jump-diffusion. The residual-diffusion, obtained by subtracting the jump-diffusion from the total diffusion, approximately follows the SER for different compositions and temperatures. We also performed hydrogen (H-)bond dynamics and observed that the contribution of jump-diffusion is proportional to the total free energy of activation of breaking all H-bonds that exist around a molecule. This study, therefore, suggests that the more a molecule is trapped by H-bonding, the more likely it is to diffuse through the jump-diffusion mechanism, eventually leading to an increasing degree of SER breakdown.
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Affiliation(s)
- Shivam Dueby
- Department of Chemistry, Indian Institute of Technology Patna, Bihar 801106, India.
| | - Vikas Dubey
- Department of Chemistry, Indian Institute of Technology Patna, Bihar 801106, India.
| | - Sandipa Indra
- Department of Chemistry, Indian Institute of Technology Patna, Bihar 801106, India.
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Baksi A, Biswas R. Dynamical Anomaly of Aqueous Amphiphilic Solutions: Connection to Solution H-Bond Fluctuation Dynamics? ACS OMEGA 2022; 7:10970-10984. [PMID: 35415359 PMCID: PMC8991915 DOI: 10.1021/acsomega.1c06831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
We have investigated the possible connection between "dynamical anomaly" observed in time-resolved fluorescence measurements of reactive and nonreactive solute-centered relaxation dynamics in aqueous binary mixtures of different amphiphiles and the solution intra- and interspecies H-bond fluctuation dynamics. Earlier studies have connected the anomalous thermodynamic properties of binary mixtures at very low amphiphile concentrations to the structural distortion of water. This is termed as "structural anomaly." Interestingly, the abrupt changes in the composition-dependent average rates of solute relaxation dynamics occur at amphiphile mole fractions approximately twice as large as those where structural anomalies appear. We have investigated this anomalous solution dynamical aspect by considering (water + tertiary butanol) as a model system and performed molecular dynamics simulations at several tertiary butanol (TBA) concentrations covering the extremely dilute to the moderately concentrated regimes. The "dynamical anomaly" has been followed via monitoring the composition dependence of the intra- and interspecies H-bond fluctuations and reorientational relaxations of TBA and water molecules. Solution structural aspects have been followed via examining the tetrahedral order parameter, radial and spatial distribution functions, numbers of H bonds per water and TBA molecules, and the respective populations participating in H-bond formation. Our simulations reveal abrupt changes in the H-bond fluctuations and reorientational dynamics and tetrahedral order parameter at amphiphile concentrations differing approximately by a factor of 2 and corroborates well with the steady-state and the time-resolved spectroscopic measurements. This work therefore explains, following a uniform and cogent manner, both the experimentally observed structural and dynamical anomalies in microscopic terms.
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Alkali metal chlorides in DMSO–methanol binary mixtures: insights into the structural properties through molecular dynamics simulations. Theor Chem Acc 2021. [DOI: 10.1007/s00214-021-02856-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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6
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Kumar S, Sarkar S, Bagchi B. Microscopic origin of breakdown of Stokes-Einstein relation in binary mixtures: Inherent structure analysis. J Chem Phys 2020; 152:164507. [PMID: 32357772 DOI: 10.1063/5.0004725] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Aqueous binary mixtures often exhibit dramatic departure from the predicted hydrodynamic behavior when transport properties are plotted against composition. We show by inherent structure (IS) analysis that this sharp composition dependent breakdown of the Stokes-Einstein relation can be attributed to the non-monotonic variation in the average inherent structure energy of these mixtures. Further IS analysis reveals the existence of a unique ground state, stabilized by both the formation of an optimum number of H-bonds and a favorable hydrophobic interaction at this composition. The surprisingly sharp turnaround behavior observed in the effective hydrodynamic radius also owes its origin to the same combination of these two factors. Interestingly, the temperature dependence of isothermal compressibility shows a minimum at the particular composition. Extensive studies on water-dimethyl sulfoxide and water-ethanol mixtures using two different force-fields of water reveal many features that are nearly universal. A justification of this quasi-universal behavior is provided in terms of a mode-coupling theory (MCT) of viscosity, which can serve as the starting point of a remarkable correlation observed with the nearest neighbor structure, as captured by the first peaks of the radial distribution function, and the slowdown in the intermediate scattering function at intermediate wavenumbers. Therefore, the formation of the local structure captured through IS analysis can be correlated with the MCT.
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Affiliation(s)
- Shubham Kumar
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Sarmistha Sarkar
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Biman Bagchi
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
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7
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Zhang X, Wang Z, Chen Z, Li H, Zhang L, Ye J, Zhang Q, Zhuang W. Molecular Mechanism of Water Reorientation Dynamics in Dimethyl Sulfoxide Aqueous Mixtures. J Phys Chem B 2020; 124:1806-1816. [PMID: 32022564 DOI: 10.1021/acs.jpcb.0c00717] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nonmonotonic composition dependence is often observed for numerous properties in the aqueous mixtures of small amphiphilic molecules. The molecular picture underlying this structure-activity relationship, however, remains largely elusive. We herein studied water reorientation dynamics in the aqueous mixture of dimethyl sulfoxide (DMSO), which has a significant nonmonotonic composition dependence, using molecular dynamic simulation and an extended molecular jump model. The analysis indicates that this nonideal behavior is driven by the collective frame diffusion component of water reorientation, which decelerates in the water-rich regime because of the strengthened hydrogen bonds and accelerates in the water-poor regime as the hydrogen bonding network is broken into smaller aggregates. The current work therefore connects the microheterogeneity in the solvation structure of DMSO-water with its nonmonotonic hydration dynamics and sheds new light on how microsegregation leads to the multiscale hydration nonideality in general.
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Affiliation(s)
- Xia Zhang
- College of Chemistry and Materials Science, Inner Mongolia University for Nationlities, Tongliao Inner Mongolia 028043, China
| | - Zhangtao Wang
- College of Chemistry and Chemical Engineering, Bohai University, Jinzhou, Liaoning 121013, China
| | - Zhening Chen
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 35000, China
| | - Hui Li
- College of Chemistry and Chemical Engineering, Bohai University, Jinzhou, Liaoning 121013, China
| | - Lu Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 35000, China
| | - Jinting Ye
- College of Chemistry and Materials Science, Inner Mongolia University for Nationlities, Tongliao Inner Mongolia 028043, China
| | - Qiang Zhang
- College of Chemistry and Materials Science, Inner Mongolia University for Nationlities, Tongliao Inner Mongolia 028043, China
| | - Wei Zhuang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 35000, China
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Kumar S, Sarkar S, Bagchi B. Anomalous viscoelastic response of water-dimethyl sulfoxide solution and a molecular explanation of non-monotonic composition dependence of viscosity. J Chem Phys 2019; 151:194505. [PMID: 31757141 DOI: 10.1063/1.5126381] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Amphiphilic molecules such as dimethyl sulfoxide (DMSO) and its aqueous binary mixtures exhibit pronounced nonideality in composition dependence of several static and dynamic properties. We carry out detailed molecular dynamics simulations to calculate various properties including viscosity of the mixture and combine the results with a mode coupling theory analysis to show that this nonideality can be attributed to local structures that are stable on a short time scale but transient on a long time scale to maintain the large scale homogeneity of the solution. Although the existence of such quasistable structures has been deciphered from spectroscopy, a detailed characterization does not exist. We calculate stress-stress autocorrelation functions (SACFs) of water-DMSO binary mixtures. We employ two different models of water, SPC/E and TIP4P/2005, to check the consistency of our results. Viscosity shows a pronounced nonmonotonic composition dependence. The calculated values are in good agreement with the experimental results. Fourier transform of SACF provides frequency-dependent viscosity. The frequency-dependent viscosity (that is, viscoelasticity) is also found to be strongly dependent on composition. Viscoelasticity exhibits sharp peaks due to intramolecular vibrational modes of DMSO, which are also seen in the density of states. We evaluate the wavenumber dependent dynamic structure factor and wavenumber dependent relaxation time. The latter also exhibits a sharp nonmonotonic composition dependence. The calculated dynamic structure factor is used in mode coupling theory expression of viscosity to obtain a semiquantitative understanding of anomalous composition dependence of viscosity. Both the self-diffusion coefficients and rotational correlation times of water and DMSO molecules exhibit nonmonotonic composition dependence.
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Affiliation(s)
- Shubham Kumar
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Sarmistha Sarkar
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Biman Bagchi
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
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9
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Daschakraborty S. How do glycerol and dimethyl sulphoxide affect local tetrahedral structure of water around a nonpolar solute at low temperature? Importance of preferential interaction. J Chem Phys 2018; 148:134501. [PMID: 29626866 DOI: 10.1063/1.5019239] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Glycerol and dimethyl sulphoxide (DMSO) have vital roles in cryoprotection of living cells, tissues, etc. The above action has been directly linked with disruption of hydrogen (H-) bond structure and dynamics of water by these cosolvents at bulk region and around various complex units, such as peptide, amino acid, protein, and lipid membrane. However, the disruption of the local structure of the water solvent around a purely hydrophobic solute is still not studied extensively. The latter is also important in the context of stabilization of protein from cold denaturation. Through all-atom molecular dynamics simulation, we have investigated the comparative effect of glycerol and DMSO on the orientational order of water around a nonpolar solute at -5 °C. A steady reduction of the tetrahedral order of water is observed at bulk (>10 Å distance from the solute) and solute interface (<5.5 Å distance from the solute) with increasing the cosolvent concentration. Contrasting roles of glycerol and DMSO have been evidenced. While DMSO affects the H-bond structure of the interfacial water more than that of the bulk water, glycerol affects the water structure almost uniformly at all regions around the solute. Furthermore, while glycerol helps to retain water molecules at the interface, DMSO significantly reduces the water content in that region. We have put forward a plausible mechanism for these contrasting roles of these cosolvents. The solute-cosolvent hydrophobic-interaction-induced orientational alignment of an interfacial cosolvent molecule determines whether the involvement of the cosolvent molecules in H-bonding with solvent water in the interface is akin to the bulk region or not.
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10
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Zhang X, Zhang L, Jin T, Zhang Q, Zhuang W. Cosolvent effect on the dynamics of water in aqueous binary mixtures. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1424958] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Xia Zhang
- Department of Chemistry, Bohai University, Jinzhou, China
| | - Lu Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, China
| | - Tan Jin
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, China
| | - Qiang Zhang
- Department of Chemistry, Bohai University, Jinzhou, China
| | - Wei Zhuang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, China
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11
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CHAND APRAMITA, CHOWDHURI SNEHASIS. Effects of dimethyl sulfoxide on the hydrogen bonding structure and dynamics of aqueous N-methylacetamide solution. J CHEM SCI 2016. [DOI: 10.1007/s12039-016-1092-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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Indra S, Guchhait B, Biswas R. Structural anomaly and dynamic heterogeneity in cycloether/water binary mixtures: Signatures from composition dependent dynamic fluorescence measurements and computer simulations. J Chem Phys 2016; 144:124506. [DOI: 10.1063/1.4943967] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Sandipa Indra
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098, India
| | - Biswajit Guchhait
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098, India
| | - Ranjit Biswas
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098, India
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13
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Frasch DM, Spiegel DR. Experiments on tracer diffusion in aqueous and non-aqueous solvent combinations. J Chem Phys 2014; 141:124507. [PMID: 25273451 DOI: 10.1063/1.4896303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Forced Rayleigh scattering is used to study the tracer diffusion of an azobenzene in binary combinations of polar solvents, including water. In the absence of water, the tracer diffusion coefficient D in the mixture lies between the diffusion coefficients within the pure solvents, on a curve that is reasonably close to the prediction of free-volume theory. If water is present, on the other hand, the diffusion coefficient displays a minimum that is less than the smaller of the two pure-solvent values. We attempt to understand the different behavior in water by concentrating on the fairly hydrophobic nature of the solute, leading to a first solvent shell that is hydrophobic on the inside and hydrophilic on the outside. We also believe that clusters of amphiphiles explain the observation that, in aqueous combinations, D is nearly constant above a certain amphiphile mole fraction.
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Affiliation(s)
- Duncan M Frasch
- Department of Physics and Astronomy, Trinity University, San Antonio, Texas 78212, USA
| | - Daniel R Spiegel
- Department of Physics and Astronomy, Trinity University, San Antonio, Texas 78212, USA
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14
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Chowdhuri S, Pattanayak SK. Pressure dependence on the single-particle dynamics and hydrogen-bond structural relaxation of water–DMSO mixtures under ambient and cold conditions. Mol Phys 2012. [DOI: 10.1080/00268976.2012.707692] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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15
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Chakraborty D, Chandra A. Voids and necks in liquid ammonia and their roles in diffusion of ions of varying size. J Comput Chem 2012; 33:843-52. [DOI: 10.1002/jcc.22910] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 10/30/2011] [Accepted: 11/20/2011] [Indexed: 11/05/2022]
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16
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Basilevsky M, Odinokov A, Nikitina E, Petrov N. The dielectric continuum solvent model adapted for treating preferential solvation effects. J Electroanal Chem (Lausanne) 2011. [DOI: 10.1016/j.jelechem.2010.09.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Gupta R, Chandra A. Nonideality in diffusion of ionic and neutral solutes and hydrogen bond dynamics in dimethyl sulfoxide-chloroform mixtures of varying composition. J Comput Chem 2011; 32:2679-89. [DOI: 10.1002/jcc.21849] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Revised: 04/14/2011] [Accepted: 05/10/2011] [Indexed: 12/11/2022]
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18
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Abazari A, Elliott JAW, Law GK, McGann LE, Jomha NM. A biomechanical triphasic approach to the transport of nondilute solutions in articular cartilage. Biophys J 2010; 97:3054-64. [PMID: 20006942 DOI: 10.1016/j.bpj.2009.08.058] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 08/19/2009] [Accepted: 08/24/2009] [Indexed: 11/26/2022] Open
Abstract
Biomechanical models for biological tissues such as articular cartilage generally contain an ideal, dilute solution assumption. In this article, a biomechanical triphasic model of cartilage is described that includes nondilute treatment of concentrated solutions such as those applied in vitrification of biological tissues. The chemical potential equations of the triphasic model are modified and the transport equations are adjusted for the volume fraction and frictional coefficients of the solutes that are not negligible in such solutions. Four transport parameters, i.e., water permeability, solute permeability, diffusion coefficient of solute in solvent within the cartilage, and the cartilage stiffness modulus, are defined as four degrees of freedom for the model. Water and solute transport in cartilage were simulated using the model and predictions of average concentration increase and cartilage weight were fit to experimental data to obtain the values of the four transport parameters. As far as we know, this is the first study to formulate the solvent and solute transport equations of nondilute solutions in the cartilage matrix. It is shown that the values obtained for the transport parameters are within the ranges reported in the available literature, which confirms the proposed model approach.
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Affiliation(s)
- Alireza Abazari
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, Canada
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19
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Basilevsky M, Odinokov A, Nikitina E, Grigoriev F, Petrov N, Alfimov M. Preferential solvation of spherical ions in binary DMSO/benzene mixtures. J Chem Phys 2009; 130:024504. [DOI: 10.1063/1.3010707] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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20
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Gupta R, Chandra A. Single particle and pair dynamics in water–formic acid mixtures containing ionic and neutral solutes: Nonideality in dynamical properties. J Chem Phys 2008; 128:184506. [DOI: 10.1063/1.2913058] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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21
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Non-ideality in Born-free energy of solvation in alcohol-water and dimethylsulfoxide-acetonitrile mixtures: Solvent size ratio and ion size dependence. J CHEM SCI 2008. [DOI: 10.1007/s12039-007-0051-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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22
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Kashyap HK, Biswas R. Ions in a binary asymmetric dipolar mixture: Mole fraction dependent Born energy of solvation and partial solvent polarization structure. J Chem Phys 2007; 127:184502. [DOI: 10.1063/1.2792953] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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23
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Gupta R, Chandra A. Nonideality in diffusion of ionic and hydrophobic solutes and pair dynamics in water-acetone mixtures of varying composition. J Chem Phys 2007; 127:024503. [PMID: 17640133 DOI: 10.1063/1.2751192] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We have performed a series of molecular dynamics simulations of water-acetone mixtures containing either an ionic solute or a neutral hydrophobic solute to study the extent of nonideality in the dynamics of these solutes with variation of composition of the mixtures. The diffusion coefficients of the charged solutes, both cationic and anionic, are found to change nonmonotonically with the composition of the mixtures showing strong nonideality of their dynamics. Also, the extent of nonideality in the diffusion of these charged solutes is found to be similar to the nonideality that is observed for the diffusion and orientational relaxation of water and acetone molecules in these mixtures which show a somewhat similar changes in the solvation characteristics of charged and dipolar solutes with changes of composition of water-acetone mixtures. The diffusion of the hydrophobic solute, however, shows a monotonic increase with increase of acetone concentration showing its different solvation characteristics as compared to the charged and dipolar solutes. The links between the nonideality in diffusion and solvation structures are further confirmed through calculations of the relevant solute-solvent and solvent-solvent radial distribution functions for both ionic and hydrophobic solutes. We have also calculated various pair dynamical properties such as the relaxation of water-water and acetone-water hydrogen bonds and residence dynamics of water molecules in water and acetone hydration shells. The lifetimes of both water-water and acetone-water hydrogen bonds and also the residence times of water molecules are found to increase steadily with increase in acetone concentration. No maximum or minimum was found in the composition dependence of these pair dynamical quantities. The lifetimes of water-water hydrogen bonds are always found to be longer than that of acetone-water hydrogen bonds in these mixtures. The residence times of water molecules are also found to follow a similar trend.
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Affiliation(s)
- Rini Gupta
- Department of Chemistry, Indian Institute of Technology, Kanpur, India 208016
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Sando GM, Dahl K, Owrutsky JC. Vibrational Spectroscopy and Dynamics of Azide Ion in Ionic Liquid and Dimethyl Sulfoxide Water Mixtures. J Phys Chem B 2007; 111:4901-9. [PMID: 17388412 DOI: 10.1021/jp067143d] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Steady-state and time-resolved infrared spectroscopy of the azide (N(3)-) anion has been used to characterize aqueous mixtures both with the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF(4)]) and with dimethyl sulfoxide (DMSO). In the DMSO-water mixtures, two anion vibrational bands are observed for low water mole fractions (0 > X(w) > 0.25), which indicates a heterogeneous ion solvation environment. The band at 2000 cm(-1) observed for neat DMSO does not shift but decreases in amplitude as the amount of water is increased. Another band appears at slightly higher frequency at low X(w) (=0.05). As the amount of water is increased, this band shifts to higher frequency and becomes stronger and is attributed to azide with an increasing degree of hydration. At intermediate and high X(w), a single band is observed that shifts almost linearly with water mole fraction toward the bulk water value. The heterogeneity is evident from the infrared pump-probe studies in which the decay times depend on probe frequency at low mole fraction. For the azide spectra in IL-water mixtures, a single azide band is observed for each mole fraction mixture. The azide band shifts almost linearly with mole fraction, indicating nearly ideal mixing behavior. As with the DMSO-water mixtures, the time-resolved IR decay times are probe-frequency-dependent at low mole fraction, again indicating heterogeneous solvation. In both the DMSO and IL mixtures with water, the relaxation times are slower than would be expected from ideal mixing, suggesting that vibrational relaxation of azide is more sensitive than its vibrational frequency to the solvent structure. The results are discussed in terms of preferential solvation and the degree to which the azide shift and vibrational relaxation depend on the degree of water association in the mixtures.
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Affiliation(s)
- Gerald M Sando
- U.S. Naval Research Laboratory, Washington, District of Columbia 20375-5342, USA
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Ghorai PK, Yashonath S. Existence of a size-dependent diffusivity maximum for uncharged solutes in water and its implications. J Phys Chem B 2006; 110:12072-9. [PMID: 16800518 DOI: 10.1021/jp060032u] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent studies suggest that there exists a size-dependent diffusivity maximum in binary mixtures interacting via Lennard-Jones potential when the size of one of the two components is varied (Ghorai, P. K.; Yashonath, S. J. Phys. Chem., 2005, 109, 5824). We discuss in the present paper the importance of the existence of a size-dependent maximum for an uncharged solute in liquid or amorphous solid water and its relation to the ionic conductivity maximum in water. We report molecular dynamics investigations into the size dependence of the self-diffusivity, D, of the uncharged solutes in water at low temperatures (30 K) with immobile as well as mobile water. We find that a maximum in self-diffusivity exists as a function of the size of solute diffusing within water at low temperatures but not at high temperatures. This is due to the relatively weak interactions between the solute and the water compared to the kinetic energy at room temperature. Previously, we have shown that a similar maximum exists for guests sorbed in zeolites and is known as the levitation effect (LE). Thus, it appears that the existence of a size-dependent maximum is universal and extends from zeolites to simple liquids to solvents of polyatomic species. We examine the implications of this for the size-dependent maximum in ionic conductivity in polar solvents known for over a hundred years. These results support the view that the size-dependent maximum seen for ions in water has its origin in the LE (see Ghorai, P. Kr.; Yashonath, S.; Lynden-Bell, R. M. J. Phys. Chem. 2005, 109, 8120).
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Affiliation(s)
- Pradip Kr Ghorai
- Solid State and Structural Chemistry Unit and Center for Condensed Matter Theory, Indian Institute of Science, Bangalore-560012, India
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Ghorai PK, Yashonath S. Evidence in Support of Levitation Effect as the Reason for Size Dependence of Ionic Conductivity in Water: A Molecular Dynamics Simulation. J Phys Chem B 2006; 110:12179-90. [PMID: 16800534 DOI: 10.1021/jp061511w] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
We report extensive molecular dynamics simulations of (i) model ions in water at high concentrations as a function of the size and charge of the ion as well as (ii) realistic simulation of Cl- and Br- ions at low concentrations in water at room temperature. We also analyze existing experimental data in light of the results obtained here. The halide ion simulations have been carried out using the interaction potentials of Koneshan et al. (J. Phys. Chem. B 1998, 102, 4193). We compute structural and dynamical properties of ions in water and explore their variation with size and charge of the ion. We find that ions of certain intermediate sizes exhibit a maximum in self-diffusivity in agreement with previous experimental measurements and computer simulations. We analyze molecular dynamics trajectories in light of the previous understanding of the levitation effect (LE) and the recent suggestion that ionic conductivity has its origin in LE (J. Phys. Chem. B 2005, 109, 8120). We report the distribution of void and neck radii that exist amidst water. Our analysis suggests that the ion with maximum self-diffusivity is characterized by a lower activation energy and a single-exponential decay of F(s)(k,t). The behavior of these and other related quantities of the ion with maximum self-diffusivity are characteristic of the anomalous regime of the LE. The simulation results of Br- and Cl- ions in water also yield results in agreement with the predictions of LE. A plot of experimental conductivity data in the literature for alkali ions in water by Kay and Evans (J. Phys. Chem. 1966, 70, 2325) also yields a lower activation energy for the ion with maximum conductivity in excellent agreement with the LE. To the best of our knowledge, none of the existing theories predict a lower activation energy for the ion with maximum conductivity.
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Affiliation(s)
- Pradip Kr Ghorai
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore-560012, India
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Plummer R, Hill DJT, Whittaker AK. DOSY NMR Studies of Chemical Exchange Behavior of Poly(2-hydroxyethyl methacrylate). Macromolecules 2006. [DOI: 10.1021/ma060355o] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ronda Plummer
- Centre for Magnetic Resonance and Australian Institute for Bioengineering and Nanotechnology, University of Queensland, QLD 4072, Australia
| | - David J. T. Hill
- Centre for Magnetic Resonance and Australian Institute for Bioengineering and Nanotechnology, University of Queensland, QLD 4072, Australia
| | - Andrew K. Whittaker
- Centre for Magnetic Resonance and Australian Institute for Bioengineering and Nanotechnology, University of Queensland, QLD 4072, Australia
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Chowdhuri S, Chandra A. Solute size effects on the solvation structure and diffusion of ions in liquid methanol under normal and cold conditions. J Chem Phys 2006; 124:084507. [PMID: 16512729 DOI: 10.1063/1.2172598] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We have performed a series of molecular dynamics simulations of alkali metal (Li+, Na+, K+, Rb+, and Cs+) and halide (F-, Cl-, Br-, and I-) ions in liquid methanol at two different temperatures to investigate the effects of ion size on the hydration structure and diffusion of ions in methanol under normal and cold conditions. Simulations are also carried out for some of the larger cations such as I+, (CH3)4N+, and (C2H5)4N+ and also neutral alkali metal atoms in methanol at both temperatures. With the increase of ion size, the diffusion coefficients of both positive and negative ions are found to show anomalous behavior. For cations, it is found that the maximum of the diffusion coefficient versus ion size curve occurs at the rather large cation of (CH3)4N+ unlike in water where the maximum occurs at the relatively smaller ion of Rb+. For halide ions, the anomalous behavior, i.e., the increase of diffusion with ion size, continues up to iodide ion and no maximum is observed. These results are in good agreement with experimental observations. The diffusion coefficients of neutral atoms are found to be greater in methanol than that in water and they decrease monotonically with solute size, whereas the diffusion coefficients of the corresponding ions are found to be smaller in methanol. Accordingly, an ion experiences a smaller Stokes friction and a higher dielectric friction in methanol than in water. These contrasting effects are believed to be responsible for the shift of the maximum of ion diffusion toward a larger ion size when compared with similar anomalous size dependence in liquid water.
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Affiliation(s)
- Snehasis Chowdhuri
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
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Chowdhuri S, Chandra A. Dynamics of ionic and hydrophobic solutes in water-methanol mixtures of varying composition. J Chem Phys 2005; 123:234501. [PMID: 16392925 DOI: 10.1063/1.2137702] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have carried out a series of molecular-dynamics simulations of water-methanol mixtures containing either an ionic or a neutral atomic solute to investigate the effects of composition of the mixture on the diffusion of these solutes. Altogether, we have considered 17 different systems of varying composition ranging from pure water to pure methanol. The diffusion coefficients of ionic solutes are found to show nonideal behavior with variation of composition of the solvent mixture. The extent of nonideality of the solute diffusion is found to be similar to the nonideality that is observed for the diffusion and orientational relaxation of water and methanol molecules in these mixtures and is attributed to the enhanced stability of the hydrogen bonds and formation of interspecies complexes in the mixtures. The neutral solute shows characteristics of hydrophobic solvation and its diffusion decreases monotonically with increase of methanol concentration. The present simulation results are compared with those of experiments wherever available.
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Affiliation(s)
- Snehasis Chowdhuri
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
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Chang HC, Jiang JC, Su CC, Lu LC, Hsiao CJ, Chuang CW, Lin SH. Pressure-Enhanced C−H···O Interactions in Aqueous tert-Butyl Alcohol. J Phys Chem A 2004. [DOI: 10.1021/jp046964k] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Hai-Chou Chang
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan, Republic of China, Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan, Republic of China, Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan, Republic of China, and Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, Republic of China
| | - Jyh-Chiang Jiang
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan, Republic of China, Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan, Republic of China, Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan, Republic of China, and Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, Republic of China
| | - Chih-Chia Su
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan, Republic of China, Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan, Republic of China, Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan, Republic of China, and Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, Republic of China
| | - Li-Chuan Lu
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan, Republic of China, Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan, Republic of China, Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan, Republic of China, and Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, Republic of China
| | - Chia-Jung Hsiao
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan, Republic of China, Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan, Republic of China, Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan, Republic of China, and Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, Republic of China
| | - Ching-Wei Chuang
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan, Republic of China, Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan, Republic of China, Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan, Republic of China, and Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, Republic of China
| | - Sheng Hsien Lin
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan, Republic of China, Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan, Republic of China, Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan, Republic of China, and Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, Republic of China
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