1
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Cho S, Kim HK, Kim TH, Cha W, Cho HR. Thermodynamic Studies on the Hydrolysis of Trivalent Plutonium and Solubility of Pu(OH) 3(am). Inorg Chem 2022; 61:12643-12651. [PMID: 35921136 DOI: 10.1021/acs.inorgchem.2c01590] [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 temperature-dependent reaction properties of actinide elements are of particular interest in the safety assessment of high-level radioactive waste (HLRW) disposal systems. In this study, the hydrolysis of Pu(III) and the solubility of Pu(OH)3(am) were investigated at various temperatures (10-40 °C) in 0.1 M NaClO4. A strong reducing condition for maintaining the oxidation state of Pu(III) while slowly increasing the pH of the solution was realized by electrolysis. The formation constants of the first hydrolysis species, log *β1', and the solubility products of Pu(OH)3(am), log *Ks,0', at 10, 17, and 40 °C were experimentally determined using spectrophotometry, laser-induced breakdown detection, and radiometry. The enthalpy and entropy changes for these reactions were estimated using the van't Hoff equation. The first hydrolysis of Pu(III) is endothermic (ΔrHm° = 34.10 ± 4.48 kJ mol-1), and the dissolution of Pu(OH)3(am) is exothermic (ΔrHm° = -294.29 ± 23.05 kJ mol-1) with negative entropy changes. These thermodynamic data will contribute to improving the reliability of the safety assessment of HLRW disposal facilities and understanding the geochemical behavior of Pu under reducing or anoxic aqueous conditions at elevated temperatures.
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Affiliation(s)
- Sangki Cho
- Nuclear Chemistry Research Team, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea.,Department of Radiochemistry and Nuclear Nonproliferation, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Hee-Kyung Kim
- Nuclear Chemistry Research Team, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea
| | - Tae-Hyeong Kim
- Nuclear Chemistry Research Team, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea
| | - Wansik Cha
- Nuclear Chemistry Research Team, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea
| | - Hye-Ryun Cho
- Nuclear Chemistry Research Team, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea.,Department of Radiochemistry and Nuclear Nonproliferation, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
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2
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Yang X, Ji M, Zhang C, Yang X, Xu Z. Physical insight into the entropy-driven ion association. J Comput Chem 2022; 43:1621-1632. [PMID: 35801676 DOI: 10.1002/jcc.26963] [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: 04/08/2022] [Revised: 06/15/2022] [Accepted: 06/20/2022] [Indexed: 11/09/2022]
Abstract
The ion association is widely believed to be dominated by the favorable entropy change arising from the release of water molecules from ion hydration shells. However, no direct thermodynamic evidence exists to validate the reliability and suitability of this view. Herein, we employ complicated free energy calculations to rigorously split the free energy including its entropic and enthalpic components into the water-induced contributions and ion-ion interaction terms for several ion pairs from monatomic to polyatomic ions, spanning the size range from small kosmotropes to large chaotropes (Na+ , Cs+ , Ca2+ , F- , I- , CO3 2- , and HPO4 2- ). Our results successfully reveal that though ion associations are indeed determined by a delicate balance between the favorable entropy variation and the repulsive enthalpy change, the entropy gain dominated by the solvent occurs only for the monatomic ion pairing. The water-induced entropic contribution significantly goes against the ion pairing between polyatomic anion and cation, which is, alternatively, dominated by the favorable entropy from the ion-ion interaction term, due to the configurational arrangement of polyatomic anions involved in ion association. The structural and dynamic analysis demonstrates that the entropy penalty from the water phase is primarily ascribed to the enhanced stability of water molecules around the cation imposed by the incoming anion. Our study successfully provides a fundamental understanding of water-mediated ion associations and highlights disparate lengthscale dependencies of the dehydration thermodynamics on the specific types of ions.
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Affiliation(s)
- Xiao Yang
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, China
| | - Mingyu Ji
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, China
| | - Cong Zhang
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, China
| | - Xiaoning Yang
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, China
| | - Zhijun Xu
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, China.,Zhangjiagang Institute of Nanjing Tech University, Zhangjiagang, China
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3
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Messias A, C da Silva DA, Fileti EE. Salt-in-water and water-in-salt electrolytes: the effects of the asymmetry in cation and anion valence on their properties. Phys Chem Chem Phys 2021; 24:336-346. [PMID: 34889921 DOI: 10.1039/d1cp04259a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We investigated the structural, dynamic, energetic, and electrostatic properties of electrolytes based on the ion pairs LiCl and Li2SO4. Atomistic molecular dynamics simulations were used to simulate these aqueous electrolytic solutions at two different concentrations 2 M (normal) and 21 M (superconcentrated, WiSE). The effects of the valence asymmetry of the Li2SO4 electrolyte were also discussed for both salt concentrations. Our results differ in the physical aspect of pure electrolytes, showing the drastic effect of high concentration, in particular on the viscosity, which is dramatically increased in WiSE. This is a consequence of their reduced ionic mobility and has a direct effect on ionic conductivity. Also, our results for graphene-based supercapacitors, as indicated by some experimental work, do not indicate any better performance of WiSEs over normal electrolytes. In fact, the differences in the total capacitance, due to the concentration of ions, presented by both electrolytes are negligible. The valence asymmetry can be clearly observed in some properties but for most of them its effects could not be quantified or isolated.
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Affiliation(s)
- Andresa Messias
- Center of Natural and Human Sciences, Federal University of ABC, 09210-170, Santo André, SP, Brazil.
| | - Débora A C da Silva
- Center for Innovation on New Energies, Advanced Energy Storage Division, Carbon Sci-Tech Labs, University of Campinas, School of Electrical and Computer Engineering, Av. Albert Einstein 400, Campinas - SP, 13083-852, Brazil
| | - Eudes E Fileti
- Institute of Science and Technology of the Federal University of São Paulo, 12247-014, São José dos Campos, SP, Brazil.
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4
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Trivedi L, Gupta K, Mishra V, Gopakumar TG, Gupta A, Vasudev PG. Crystal structure and self-assembly on graphite of a pyrazolo[1,5-c]pyrimidine derivative. Acta Crystallogr C Struct Chem 2021; 77:757-763. [PMID: 34864717 DOI: 10.1107/s2053229621011232] [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: 06/22/2021] [Accepted: 10/26/2021] [Indexed: 11/10/2022] Open
Abstract
The crystal structure of the heterocyclic compound 2-(4-methoxyphenyl)-7-phenylpyrazolo[1,5-c]pyrimidine, C19H15N3O, has been determined and its self-assembly on the surface of graphite has been examined using atomic force microscopy (AFM). The title compound crystallized in the monoclinic space group P21/c, with two independent molecules in the asymmetric unit. The packing of the L-shaped molecules in the crystal is governed by arene interactions, in the absence of any conventional hydrogen-bonding interactions. The packing arrangement reveals four types of dimeric motifs stabilized by π-π and C-H...π interactions. At low coverage, molecules assemble into long needle-like islands on the graphite surface. High-resolution AFM images reveal that the molecules interact through weak noncovalent interactions between the aromatic H atoms and the methoxy O atoms.
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Affiliation(s)
- Laxmikant Trivedi
- Plant Biotechnology Division, CSIR-Central Institute of Medicinal and Aromatic Plants, CIMAP PO, Lucknow, Uttar Pradesh 226 015, India
| | - Kratika Gupta
- Phytochemistry Division, CSIR-Central Institute of Medicinal and Aromatic Plants, CIMAP PO, Lucknow, Uttar Pradesh 226 015, India
| | - Vipin Mishra
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, UP 208 016, India
| | | | - Atul Gupta
- Phytochemistry Division, CSIR-Central Institute of Medicinal and Aromatic Plants, CIMAP PO, Lucknow, Uttar Pradesh 226 015, India
| | - Prema G Vasudev
- Plant Biotechnology Division, CSIR-Central Institute of Medicinal and Aromatic Plants, CIMAP PO, Lucknow, Uttar Pradesh 226 015, India
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5
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Kim S, Wang X, Jang J, Eom K, Clegg SL, Park G, Di Tommaso D. Hydrogen-Bond Structure and Low-Frequency Dynamics of Electrolyte Solutions: Hydration Numbers from ab Initio Water Reorientation Dynamics and Dielectric Relaxation Spectroscopy. Chemphyschem 2020; 21:2334-2346. [PMID: 32866322 PMCID: PMC7702081 DOI: 10.1002/cphc.202000498] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/31/2020] [Indexed: 11/16/2022]
Abstract
We present an atomistic simulation scheme for the determination of the hydration number (h) of aqueous electrolyte solutions based on the calculation of the water dipole reorientation dynamics. In this methodology, the time evolution of an aqueous electrolyte solution generated from ab initio molecular dynamics simulations is used to compute the reorientation time of different water subpopulations. The value of h is determined by considering whether the reorientation time of the water subpopulations is retarded with respect to bulk-like behavior. The application of this computational protocol to magnesium chloride (MgCl2 ) solutions at different concentrations (0.6-2.8 mol kg-1 ) gives h values in excellent agreement with experimental hydration numbers obtained using GHz-to-THz dielectric relaxation spectroscopy. This methodology is attractive because it is based on a well-defined criterion for the definition of hydration number and provides a link with the molecular-level processes responsible for affecting bulk solution behavior. Analysis of the ab initio molecular dynamics trajectories using radial distribution functions, hydrogen bonding statistics, vibrational density of states, water-water hydrogen bonding lifetimes, and water dipole reorientation reveals that MgCl2 has a considerable influence on the hydrogen bond network compared with bulk water. These effects have been assigned to the specific strong Mg-water interaction rather than the Cl-water interaction.
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Affiliation(s)
- Seonmyeong Kim
- Center for THz-driven Biomedical SystemDepartment of Physics and AstronomySeoul National UniversityGwanak-gu08826South Korea
- Advanced Institutes of Convergence TechnologySeoul National UniversitySuwon-SiGyeonggi-do16229South Korea
| | - Xiangwen Wang
- School of Biological and Chemical SciencesMaterials Research InstituteThomas Young CentreQueen Mary University of LondonMile End RoadLondonE1 4NSUnited Kingdom
| | - Jeongmin Jang
- Center for THz-driven Biomedical SystemDepartment of Physics and AstronomySeoul National UniversityGwanak-gu08826South Korea
- Advanced Institutes of Convergence TechnologySeoul National UniversitySuwon-SiGyeonggi-do16229South Korea
| | - Kihoon Eom
- Center for THz-driven Biomedical SystemDepartment of Physics and AstronomySeoul National UniversityGwanak-gu08826South Korea
- Advanced Institutes of Convergence TechnologySeoul National UniversitySuwon-SiGyeonggi-do16229South Korea
| | - Simon L. Clegg
- School of Environmental SciencesUniversity of East AngliaNorwichNR4 7TJUnited Kingdom
| | - Gun‐Sik Park
- Center for THz-driven Biomedical SystemDepartment of Physics and AstronomySeoul National UniversityGwanak-gu08826South Korea
- Advanced Institutes of Convergence TechnologySeoul National UniversitySuwon-SiGyeonggi-do16229South Korea
| | - Devis Di Tommaso
- School of Biological and Chemical SciencesMaterials Research InstituteThomas Young CentreQueen Mary University of LondonMile End RoadLondonE1 4NSUnited Kingdom
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6
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Wang X, Toroz D, Kim S, Clegg SL, Park GS, Di Tommaso D. Density functional theory based molecular dynamics study of solution composition effects on the solvation shell of metal ions. Phys Chem Chem Phys 2020; 22:16301-16313. [PMID: 32647838 DOI: 10.1039/d0cp01957g] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present an ab initio molecular dynamics study of the alkali metal ions Li+, Na+, K+ and Cs+, and of the alkaline earth metal ions Mg2+ and Ca2+ in both pure water and electrolyte solutions containing the counterions Cl- and SO42-. Simulations were conducted using different density functional theory methods (PBE, BLYP and revPBE), with and without the inclusion of dispersion interactions (-D3). Analysis of the ion-water structure and interaction strength, water exchange between the first and second hydration shell, and hydrogen bond network and low-frequency reorientation dynamics around the metal ions have been used to characterise the influence of solution composition on the ionic solvation shell. Counterions affect the properties of the hydration shell not only when they are directly coordinated to the metal ion, but also when they are at the second coordination shell. Chloride ions reduce the sodium hydration shell and expand the calcium hydration shell by stabilizing under-coordinated hydrated Na(H2O)5+ complexes and over-coordinated Ca(H2O)72+. The same behaviour is observed in CaSO4(aq), where Ca2+ and SO42- form almost exclusively solvent-shared ion pairs. Water exchange between the first and second hydration shell around Ca2+ in CaSO4(aq) is drastically decelerated compared with the simulations of the hydrated metal ion (single Ca2+, no counterions). Velocity autocorrelation function analysis, used to probe the strength of the local ion-water interaction, shows a smoother decay of Mg2+ in MgCl2(aq), which is a clear indication of a looser inter-hexahedral vibration in the presence of chloride ions located in the second coordination shell of Mg2+. The hydrogen bond statistics and orientational dynamics in the ionic solvation shell show that the influence on the water-water network cannot only be ascribed to the specific cation-water interaction, but also to the subtle interplay between the level of hydration of the ions, and the interactions between ions, especially those of opposite charge. As many reactive processes involving solvated metal ions occur in environments that are far from pure water but rich in ions, this computational study shows how the solution composition can result in significant differences in behaviour and function of the ionic solvation shell.
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Affiliation(s)
- Xiangwen Wang
- School of Biological and Chemical Sciences, Materials Research Institute, Thomas Young Centre, Queen Mary University of London, Mile End Road, E1 4NS, London, UK.
| | - Dimitrios Toroz
- School of Biological and Chemical Sciences, Materials Research Institute, Thomas Young Centre, Queen Mary University of London, Mile End Road, E1 4NS, London, UK.
| | - Seonmyeong Kim
- Center for THz-driven Biological Systems, Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea and Advanced Institutes of Convergence Technology, Seoul National University, Suwon-Si, Gyeonggi-do 16229, Republic of Korea
| | - Simon L Clegg
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Gun-Sik Park
- Center for THz-driven Biological Systems, Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea and Advanced Institutes of Convergence Technology, Seoul National University, Suwon-Si, Gyeonggi-do 16229, Republic of Korea
| | - Devis Di Tommaso
- School of Biological and Chemical Sciences, Materials Research Institute, Thomas Young Centre, Queen Mary University of London, Mile End Road, E1 4NS, London, UK.
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7
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Zhang C, Giberti F, Sevgen E, de Pablo JJ, Gygi F, Galli G. Dissociation of salts in water under pressure. Nat Commun 2020; 11:3037. [PMID: 32546791 PMCID: PMC7298052 DOI: 10.1038/s41467-020-16704-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 05/15/2020] [Indexed: 11/09/2022] Open
Abstract
The investigation of salts in water at extreme conditions is crucial to understanding the properties of aqueous fluids in the Earth. We report first principles (FP) and classical molecular dynamics simulations of NaCl in the dilute limit, at temperatures and pressures relevant to the Earth’s upper mantle. Similar to ambient conditions, we observe two metastable states of the salt: the contact (CIP) and the solvent-shared ion-pair (SIP), which are entropically and enthalpically favored, respectively. We find that the free energy barrier between the CIP and SIP minima increases at extreme conditions, and that the stability of the CIP is enhanced in FP simulations, consistent with the decrease of the dielectric constant of water. The minimum free energy path between the CIP and SIP becomes smoother at high pressure, and the relative stability of the two configurations is affected by water self-dissociation, which can only be described properly by FP simulations. Salts in water at extreme conditions play a fundamental role in determining the properties of the Earthʼs mantle constituents. Here the authors shed light on ion-water and ion-ion interactions for NaCl dissolved in water at conditions relevant to the Earthʼs upper mantle by molecular dynamics simulations.
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Affiliation(s)
- Cunzhi Zhang
- Department of Materials Science and Engineering, COE, Peking University, 100871, Beijing, China
| | - Federico Giberti
- University of Chicago, 5640 S. Ellis Ave., Chicago, IL, 60637, USA
| | - Emre Sevgen
- University of Chicago, 5640 S. Ellis Ave., Chicago, IL, 60637, USA
| | - Juan J de Pablo
- University of Chicago, 5640 S. Ellis Ave., Chicago, IL, 60637, USA.,Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Francois Gygi
- University of California Davis, Davis, CA, 95616, USA
| | - Giulia Galli
- University of Chicago, 5640 S. Ellis Ave., Chicago, IL, 60637, USA. .,Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA.
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8
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Acharya S, Nandi UK, Bhattacharyya SM. Comparative Study of Anomalous Size Dependence of Charged and Neutral Solute Diffusion in Water. J Phys Chem B 2019; 123:10275-10285. [PMID: 31697084 DOI: 10.1021/acs.jpcb.9b08023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present a comparative study of size dependence of diffusion for charged and neutral solutes in water. Although both show nonmonotonicity of the size dependence of diffusion, their nature and origin are quite different. For neutral solutes, the peak position and the value of diffusion at the maximum are both independent of the solute-water interaction. Interestingly, for charged solutes, with an increase in solute-water interaction strength, the peak position shifts to lower solute sizes and with an increase in charge, it shifts to higher solute sizes. The diffusion value at the peak reduces with an increase in both solute-water interaction and solute charge. We show that all these features observed for charged solutes can be understood in terms of the interplay between ionic and nonionic interactions which is definitely absent for neutral solutes. Some of the earlier studies addressing the nonmonotonicity in diffusion did suggest the interplay between the two interactions to be the cause. However, this is the first time we show that such an interplay gives rise to the nonmonotonicity in the potential energy which is a prerequisite for obtaining the nonmonotonicity in the diffusion. Such nonmonotonicity in the potential energy is absent for neutral solutes.
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Affiliation(s)
- Sayantan Acharya
- Polymer Science and Engineering Department , National Chemical Laboratory , Pune 411008 , India.,Academy of Scientific and Innovative Research (AcSIR) , Ghaziabad 201002 , India
| | - Ujjwal K Nandi
- Polymer Science and Engineering Department , National Chemical Laboratory , Pune 411008 , India.,Academy of Scientific and Innovative Research (AcSIR) , Ghaziabad 201002 , India
| | - Sarika Maitra Bhattacharyya
- Polymer Science and Engineering Department , National Chemical Laboratory , Pune 411008 , India.,Academy of Scientific and Innovative Research (AcSIR) , Ghaziabad 201002 , India
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9
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10
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Assaf KI, Nau WM. The Chaotropic Effect as an Assembly Motif in Chemistry. Angew Chem Int Ed Engl 2018; 57:13968-13981. [PMID: 29992706 PMCID: PMC6220808 DOI: 10.1002/anie.201804597] [Citation(s) in RCA: 194] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/01/2018] [Indexed: 11/26/2022]
Abstract
Following up on scattered reports on interactions of conventional chaotropic ions (for example, I- , SCN- , ClO4- ) with macrocyclic host molecules, biomolecules, and hydrophobic neutral surfaces in aqueous solution, the chaotropic effect has recently emerged as a generic driving force for supramolecular assembly, orthogonal to the hydrophobic effect. The chaotropic effect becomes most effective for very large ions that extend beyond the classical Hofmeister scale and that can be referred to as superchaotropic ions (for example, borate clusters and polyoxometalates). In this Minireview, we present a continuous scale of water-solute interactions that includes the solvation of kosmotropic, chaotropic, and hydrophobic solutes, as well as the creation of void space (cavitation). Recent examples for the association of chaotropic anions to hydrophobic synthetic and biological binding sites, lipid bilayers, and surfaces are discussed.
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Affiliation(s)
- Khaleel I. Assaf
- Department of Life Sciences and ChemistryJacobs University BremenCampus Ring 128759BremenGermany
| | - Werner M. Nau
- Department of Life Sciences and ChemistryJacobs University BremenCampus Ring 128759BremenGermany
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11
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Affiliation(s)
- Khaleel I. Assaf
- Department of Life Sciences and Chemistry; Jacobs University Bremen; Campus Ring 1 28759 Bremen Deutschland
| | - Werner M. Nau
- Department of Life Sciences and Chemistry; Jacobs University Bremen; Campus Ring 1 28759 Bremen Deutschland
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12
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Heyden M. Disassembling solvation free energies into local contributions—Toward a microscopic understanding of solvation processes. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2018. [DOI: 10.1002/wcms.1390] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Matthias Heyden
- School of Molecular Sciences Arizona State University Tempe Arizona
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13
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Kulkarni M, Yang C, Pak Y. Refined Alkali Metal Ion Parameters for the OPC Water Model. B KOREAN CHEM SOC 2018. [DOI: 10.1002/bkcs.11527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mandar Kulkarni
- Department of Chemistry and Institute of Functional Materials; Pusan National University; Busan 609-735 South Korea
| | - Changwon Yang
- Department of Chemistry and Institute of Functional Materials; Pusan National University; Busan 609-735 South Korea
| | - Youngshang Pak
- Department of Chemistry and Institute of Functional Materials; Pusan National University; Busan 609-735 South Korea
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14
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Hofer TS, Hünenberger PH. Absolute proton hydration free energy, surface potential of water, and redox potential of the hydrogen electrode from first principles: QM/MM MD free-energy simulations of sodium and potassium hydration. J Chem Phys 2018; 148:222814. [DOI: 10.1063/1.5000799] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Thomas S. Hofer
- Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry, Centre for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria
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15
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Sehnem AL, Niether D, Wiegand S, Figueiredo Neto AM. Thermodiffusion of Monovalent Organic Salts in Water. J Phys Chem B 2018; 122:4093-4100. [DOI: 10.1021/acs.jpcb.8b01152] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Doreen Niether
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Simone Wiegand
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
- Department für Chemie - Physikalische Chemie, Universität zu Köln, 50939 Cologne, Germany
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16
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Ion-induced alterations of the local hydration environment elucidate Hofmeister effect in a simple classical model of Trp-cage miniprotein. J Mol Model 2017; 23:298. [PMID: 28956172 DOI: 10.1007/s00894-017-3471-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 09/10/2017] [Indexed: 10/18/2022]
Abstract
Protein stability is known to be influenced by the presence of Hofmeister active ions in the solution. In addition to direct ion-protein interactions, this influence manifests through the local alterations of the interfacial water structure induced by the anions and cations present in this region. In our earlier works it was pointed out that the effects of Hofmeister active salts on the stability of Trp-cage miniprotein can be modeled qualitatively using non-polarizable force fields. These simulations reproduced the structure-stabilization and structure-destabilization effects of selected kosmotropic and chaotropic salts, respectively. In the present study we use the same model system to elucidate atomic processes behind the chaotropic destabilization and kosmotropic stabilization of the miniprotein. We focus on changes of the local hydration environment of the miniprotein upon addition of NaClO4 and NaF salts to the solution. The process is separated into two parts. In the first, 'promotion' phase, the protein structure is fixed, and the local hydration properties induced by the simultaneous presence of protein and ions are investigated, with a special focus on the interaction of Hofmeister active anions with the charged and polar sites. In the second, 'rearrangement' phase we follow changes of the hydration of ions and the protein, accompanying the conformational relaxation of the protein. We identify significant factors of an enthalpic and entropic nature behind the ion-induced free energy changes of the protein-water system, and also propose a possible atomic mechanism consistent with the Collins's rule, for the chaotropic destabilization and kosmotropic stabilization of protein conformation.
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17
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Persson RAX, Pattni V, Singh A, Kast SM, Heyden M. Signatures of Solvation Thermodynamics in Spectra of Intermolecular Vibrations. J Chem Theory Comput 2017; 13:4467-4481. [PMID: 28783431 PMCID: PMC5607457 DOI: 10.1021/acs.jctc.7b00184] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
![]()
This
study explores the thermodynamic and vibrational properties
of water in the three-dimensional environment of solvated ions and
small molecules using molecular simulations. The spectrum of intermolecular
vibrations in liquid solvents provides detailed information on the
shape of the local potential energy surface, which in turn determines
local thermodynamic properties such as the entropy. Here, we extract
this information using a spatially resolved extension of the two-phase
thermodynamics method to estimate hydration water entropies based
on the local vibrational density of states (3D-2PT). Combined with
an analysis of solute–water and water–water interaction
energies, this allows us to resolve local contributions to the solvation
enthalpy, entropy, and free energy. We use this approach to study
effects of ions on their surrounding water hydrogen bond network,
its spectrum of intermolecular vibrations, and resulting thermodynamic
properties. In the three-dimensional environment of polar and nonpolar
functional groups of molecular solutes, we identify distinct hydration
water species and classify them by their characteristic vibrational
density of states and molecular entropies. In each case, we are able
to assign variations in local hydration water entropies to specific
changes in the spectrum of intermolecular vibrations. This provides
an important link for the thermodynamic interpretation of vibrational
spectra that are accessible to far-infrared absorption and Raman spectroscopy
experiments. Our analysis provides unique microscopic details regarding
the hydration of hydrophobic and hydrophilic functional groups, which
enable us to identify interactions and molecular degrees of freedom
that determine relevant contributions to the solvation entropy and
consequently the free energy.
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Affiliation(s)
- Rasmus A X Persson
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1, DE-45470 Mülheim an der Ruhr, Germany
| | - Viren Pattni
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1, DE-45470 Mülheim an der Ruhr, Germany
| | - Anurag Singh
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1, DE-45470 Mülheim an der Ruhr, Germany.,Department of Chemistry, Indian Institute of Technology, Roorkee , IN-247667 Roorkee, Uttarakhand, India
| | - Stefan M Kast
- Physikalische Chemie III, Technische Universität Dortmund , Otto-Hahn-Straße 4a, DE-44227 Dortmund, Germany
| | - Matthias Heyden
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1, DE-45470 Mülheim an der Ruhr, Germany
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