1
|
Qian C, Zhou K. Ab Initio Molecular Dynamics Investigation of the Solvation States of Hydrated Ions in Confined Water. Inorg Chem 2023; 62:17756-17765. [PMID: 37855150 DOI: 10.1021/acs.inorgchem.3c02443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
Ionic transport in nanoscale channels with a critical size comparable to that of ions and solutes exhibits exceptional performance in water desalination, ion separation, electrocatalysts, and supercapacitors. However, the solvation states (SSs), i.e., the hydration structures and probability distribution, of hydrated ions in nanochannels differ from those in the bulk and the perspective of continuum theory. In this work, we conduct ab initio enhanced-sampling atomistic simulations to investigate the ion-specific SSs of monovalent ions (including Li+, Na+, K+, F-, Cl-, and I-) in the graphene channel with a width of 1 nm. Our findings highlight that the SSs of those ions are primarily determined by ion-water hydration, where ion-wall interactions play a minor role. The distribution of ions in layered confined water is a result of ion-specific hydration, which arises from the synergy of entropy and enthalpy. The free energy barriers for transitions between SSs are on the order of 1kBT, allowing for modulation through applying external fields or modifying surface properties. As the ion-wall interaction strengthens, as observed in vermiculite and carbides and nitrides of transition metal channels, the probability of near-wall SSs increases. These results help to improve the performance of nanofluidic devices and provide crucial insights for developing accurate force fields of molecular simulations or advanced theoretical approaches for ion dynamics in confined channels.
Collapse
Affiliation(s)
- Chen Qian
- College of Energy, Soochow Institute for Energy and Materials InnovationS (SIEMIS), Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies, Soochow University, Suzhou 215006, China
- Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon 999077, Hong Kong, China
| | - Ke Zhou
- College of Energy, Soochow Institute for Energy and Materials InnovationS (SIEMIS), Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies, Soochow University, Suzhou 215006, China
| |
Collapse
|
2
|
Hidayat Y, Rahmawati F, Nurcahyo IF, Prasetyo N, Pranowo HD. Hybrid Forces Molecular Dynamics on the Lability, Dynamics and “Structure Breaking Effect” of Cs+ in Liquid Ammonia. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20200218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yuniawan Hidayat
- Department of Chemistry, Faculty of Mathematics and Sciences, Sebelas Maret University, Jl. Ir Sutami 36A Surakarta, 57126, Indonesia
- Austria-Indonesia Centre (AIC) for Computational Chemistry, Gadjah Mada University, Jl. Sekip Utara, Yogyakarta, 55281, Indonesia
| | - Fitria Rahmawati
- Department of Chemistry, Faculty of Mathematics and Sciences, Sebelas Maret University, Jl. Ir Sutami 36A Surakarta, 57126, Indonesia
| | - IF Nurcahyo
- Department of Chemistry, Faculty of Mathematics and Sciences, Sebelas Maret University, Jl. Ir Sutami 36A Surakarta, 57126, Indonesia
| | - Niko Prasetyo
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Gadjah Mada University, Jl. Sekip Utara, Yogyakarta, 55281, Indonesia
- Austria-Indonesia Centre (AIC) for Computational Chemistry, Gadjah Mada University, Jl. Sekip Utara, Yogyakarta, 55281, Indonesia
| | - Harno Dwi Pranowo
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Gadjah Mada University, Jl. Sekip Utara, Yogyakarta, 55281, Indonesia
- Austria-Indonesia Centre (AIC) for Computational Chemistry, Gadjah Mada University, Jl. Sekip Utara, Yogyakarta, 55281, Indonesia
| |
Collapse
|
3
|
Ding Y. First principles molecular dynamics investigation on the water-ion interaction: A case of diluted CsI solution. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
4
|
Roy S, Wu L, Goverapet Srinivasan S, Stack AG, Navrotsky A, Bryantsev VS. Hydration structure and water exchange kinetics at xenotime-water interfaces: implications for rare earth minerals separation. Phys Chem Chem Phys 2020; 22:7719-7727. [PMID: 32215419 DOI: 10.1039/d0cp00087f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hydration of surface ions gives rise to structural heterogeneity and variable exchange kinetics of water at complex mineral-water interfaces. Here, we employ ab initio molecular dynamics (AIMD) simulations and water adsorption calorimetry to examine the aqueous interfaces of xenotime, a phosphate mineral that contains predominantly Y3+ and heavy rare earth elements. Consistent with natural crystal morphology, xenotime is predicted to have a tetragonal prismatic shape, dominated by the {100} surface. Hydration of this surface induces multilayer interfacial water structures with distinct OH orientations, which agrees with recent crystal truncation rod measurements. The exchange kinetics between two adjacent water layers exhibits a wide range of underlying timescales (5-180 picoseconds), dictated by ion-water electrostatics. Adsorption of a bidentate hydroxamate ligand reveals that {100} xenotime surface can only accommodate monodentate coordination with water exchange kinetics strongly depending on specific ligand orientation, prompting us to reconsider traditional strategies for selective separation of rare-earth minerals.
Collapse
Affiliation(s)
- Santanu Roy
- Chemical Sciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd., Oak Ridge, TN 37830, USA.
| | - Lili Wu
- Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | | | - Andrew G Stack
- Chemical Sciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd., Oak Ridge, TN 37830, USA.
| | - Alexandra Navrotsky
- Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Vyacheslav S Bryantsev
- Chemical Sciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd., Oak Ridge, TN 37830, USA.
| |
Collapse
|
5
|
Exploring preferential solvation, structure and dynamical properties or Rb+ in aqueous ammonia solution using ab initio Quantum Mechanical Charge Field (QMCF). J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.112027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
6
|
Abstract
AbstractThe strong, long-range electrostatic forces described by Coulomb's law disappear for ions in water, and the behavior of these ions is instead controlled by their water affinity – a weak, short-range force which arises from their charge density. This was established experimentally in the mid-1980s by size-exclusion chromatography on carefully calibrated Sephadex®G-10 (which measures the effective volume and thus the water affinity of an ion) and by neutron diffraction with isotopic substitution (which measures the density and orientation of water molecules near the diffracting ion and thus its water affinity). These conclusions have been confirmed more recently by molecular dynamics simulations, which explicitly model each individual water molecule. This surprising change in force regime occurs because the oppositely charged ions in aqueous salt solutions exist functionally as ion pairs (separated by 0, 1 or 2 water molecules) as has now been shown by dielectric relaxation spectroscopy; this cancels out the strong long-range electrostatic forces and allows the weak, short-range water affinity effects to come to the fore. This microscopic structure of aqueous salt solutions is not captured by models utilizing a macroscopic dielectric constant. Additionally, the Law of Matching Water Affinity, first described in 1997 and 2004, establishes that contact ion pair formation is controlled by water affinity and is a major determinant of the solubility of charged species since only a net neutral species can change phases.
Collapse
|
7
|
Zhuang D, Riera M, Schenter GK, Fulton JL, Paesani F. Many-Body Effects Determine the Local Hydration Structure of Cs + in Solution. J Phys Chem Lett 2019; 10:406-412. [PMID: 30629438 DOI: 10.1021/acs.jpclett.8b03829] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A systematic analysis of the hydration structure of Cs+ ions in solution is derived from simulations carried out using a series of molecular models built upon a hierarchy of approximate representations of many-body effects in ion-water interactions. It is found that a pairwise-additive model, commonly used in biomolecular simulations, provides poor agreement with experimental X-ray spectra, indicating an incorrect description of the underlying hydration structure. Although the agreement with experiment improves in simulations with a polarizable model, the predicted hydration structure is found to lack the correct sequence of water shells. Progressive inclusion of explicit many-body effects in the representation of Cs+-water interactions as well as accounting for nuclear quantum effects is shown to be necessary for quantitatively reproducing the experimental X-ray spectra. Besides emphasizing the importance of many-body effects, these results suggest that molecular models rigorously derived from many-body expansions hold promise for realistic simulations of aqueous solutions.
Collapse
Affiliation(s)
- Debbie Zhuang
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Marc Riera
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Gregory K Schenter
- Physical and Computational Sciences Directorate , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States
| | - John L Fulton
- Physical and Computational Sciences Directorate , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States
| | - Francesco Paesani
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
- Materials Science and Engineering , University of California, San Diego , La Jolla , California 92093 , United States
- San Diego Supercomputer Center , University of California, San Diego , La Jolla , California 92093 , United States
| |
Collapse
|
8
|
Roy S, Bryantsev VS. Finding Order in the Disordered Hydration Shell of Rapidly Exchanging Water Molecules around the Heaviest Alkali Cs+ and Fr+. J Phys Chem B 2018; 122:12067-12076. [DOI: 10.1021/acs.jpcb.8b08414] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Santanu Roy
- Chemical Science Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37830, United States
| | - Vyacheslav S. Bryantsev
- Chemical Science Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37830, United States
| |
Collapse
|
9
|
Zhang W, Fang C, Fang Y, Zhu F, Zhou Y, Liu H, Li W. Structure of aqueous cesium metaborate solutions by X-ray scattering and DFT calculation. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2017.12.099] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
10
|
Shilov IY, Lyashchenko AK. Modeling activity coefficients in alkali iodide aqueous solutions using the extended Debye-Hückel theory. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.05.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
11
|
Caralampio DZ, Martínez JM, Pappalardo RR, Marcos ES. The hydration structure of the heavy-alkalines Rb+ and Cs+ through molecular dynamics and X-ray absorption spectroscopy: surface clusters and eccentricity. Phys Chem Chem Phys 2017; 19:28993-29004. [DOI: 10.1039/c7cp05346k] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Hydration shells around Rb+ and Cs+ are not symmetric; the cation and the 1st-shell water mass center are separated by ∼0.4 Å, and this is supported by agreement between the theoretical and experimental EXAFS spectrum.
Collapse
Affiliation(s)
| | - José M. Martínez
- Departmento de Quimica Fisica
- Universidad de Sevilla
- 41012-Seville
- Spain
| | | | | |
Collapse
|
12
|
Barboiu M, Cazade PA, Le Duc Y, Legrand YM, van der Lee A, Coasne B. Polarized Water Wires under Confinement in Chiral Channels. J Phys Chem B 2015; 119:8707-17. [DOI: 10.1021/acs.jpcb.5b03322] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Mihail Barboiu
- Adaptive
Supramolecular Nanosystems Group, Institut Européen des Membranes, ENSCM-UM-UMR-CNRS5635, Place Eugène Bataillon CC047, 34095 Montpellier Cedex 5, France
| | - Pierre-André Cazade
- MultiScale
Materials Science for Energy and Environment, UMI 3466 CNRS-MIT and
Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Yann Le Duc
- Adaptive
Supramolecular Nanosystems Group, Institut Européen des Membranes, ENSCM-UM-UMR-CNRS5635, Place Eugène Bataillon CC047, 34095 Montpellier Cedex 5, France
| | - Yves-Marie Legrand
- Adaptive
Supramolecular Nanosystems Group, Institut Européen des Membranes, ENSCM-UM-UMR-CNRS5635, Place Eugène Bataillon CC047, 34095 Montpellier Cedex 5, France
| | - Arie van der Lee
- Adaptive
Supramolecular Nanosystems Group, Institut Européen des Membranes, ENSCM-UM-UMR-CNRS5635, Place Eugène Bataillon CC047, 34095 Montpellier Cedex 5, France
| | - Benoit Coasne
- Institut Charles Gerhardt Montpellier (ICGM), UMR 5253 CNRS/ENSCM/Université Montpellier 2, 8 rue
de l’Ecole Normale, F-34296 Montpellier, France
- MultiScale
Materials Science for Energy and Environment, UMI 3466 CNRS-MIT and
Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
13
|
Shiga M, Masia M. Boundary based on exchange symmetry theory for multilevel simulations. II. Multiple time scale approach. J Chem Phys 2013; 139:144103. [DOI: 10.1063/1.4823729] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
14
|
Smirnov PR. Structural parameters of the nearest surrounding of halide ions in the aqueous electrolyte solutions. RUSS J GEN CHEM+ 2013. [DOI: 10.1134/s107036321308001x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
15
|
Mile V, Gereben O, Kohara S, Pusztai L. On the Structure of Aqueous Cesium Fluoride and Cesium Iodide Solutions: Diffraction Experiments, Molecular Dynamics Simulations, and Reverse Monte Carlo Modeling. J Phys Chem B 2012; 116:9758-67. [DOI: 10.1021/jp301595m] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Viktória Mile
- Institute for Solid State Physics
and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
| | - Orsolya Gereben
- Institute for Solid State Physics
and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
| | - Shinji Kohara
- Japan Synchrotron Radiation Research Institute (SPring-8/JASRI), 1-1-1
Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - László Pusztai
- Institute for Solid State Physics
and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
| |
Collapse
|
16
|
Ikeda T, Boero M. Communication: Hydration structure and polarization of heavy alkali ions: A first principles molecular dynamics study of Rb+ and Cs+. J Chem Phys 2012; 137:041101. [DOI: 10.1063/1.4742151] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
|
17
|
Collins KD. Why continuum electrostatics theories cannot explain biological structure, polyelectrolytes or ionic strength effects in ion–protein interactions. Biophys Chem 2012; 167:43-59. [DOI: 10.1016/j.bpc.2012.04.002] [Citation(s) in RCA: 169] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 04/10/2012] [Accepted: 04/10/2012] [Indexed: 01/13/2023]
|
18
|
Ren CL, Tian WD, Szleifer I, Ma YQ. Specific Salt Effects on Poly(ethylene oxide) Electrolyte Solutions. Macromolecules 2011. [DOI: 10.1021/ma1027752] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Chun-lai Ren
- National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
| | - Wen-de Tian
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou 215006, China
| | - Igal Szleifer
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Yu-qiang Ma
- National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou 215006, China
| |
Collapse
|
19
|
Mile V, Gereben O, Kohara S, Pusztai L. On the structure of aqueous cesium bromide solutions: Diffraction experiments, molecular dynamics simulations and Reverse Monte Carlo modeling. J Mol Liq 2010. [DOI: 10.1016/j.molliq.2010.08.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
20
|
Mile V, Pusztai L, Dominguez H, Pizio O. Understanding the Structure of Aqueous Cesium Chloride Solutions by Combining Diffraction Experiments, Molecular Dynamics Simulations, and Reverse Monte Carlo Modeling. J Phys Chem B 2009; 113:10760-9. [DOI: 10.1021/jp900092g] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Viktória Mile
- Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 49, Hungary, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico (UNAM), Circuito Exterior s/n., Coyoacán, México, D. F. 04510, and Instituto de Quimica, UNAM, Circuito Exterior, Coyoacán, México, D. F. 04510
| | - László Pusztai
- Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 49, Hungary, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico (UNAM), Circuito Exterior s/n., Coyoacán, México, D. F. 04510, and Instituto de Quimica, UNAM, Circuito Exterior, Coyoacán, México, D. F. 04510
| | - Hector Dominguez
- Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 49, Hungary, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico (UNAM), Circuito Exterior s/n., Coyoacán, México, D. F. 04510, and Instituto de Quimica, UNAM, Circuito Exterior, Coyoacán, México, D. F. 04510
| | - Orest Pizio
- Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 49, Hungary, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico (UNAM), Circuito Exterior s/n., Coyoacán, México, D. F. 04510, and Instituto de Quimica, UNAM, Circuito Exterior, Coyoacán, México, D. F. 04510
| |
Collapse
|
21
|
UMEBAYASHI Y, YAMAGUCHI T, FUKUDA S, MITSUGI T, TAKEUCHI M, FUJII K, ISHIGURO SI. Raman Spectroscopic Study on Alkaline Metal Ion Solvation in 1-Butyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)amide Ionic Liquid. ANAL SCI 2008; 24:1297-304. [DOI: 10.2116/analsci.24.1297] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
| | | | - Shuhei FUKUDA
- Department of Chemistry, Faculty of Science, Kyushu University
| | - Takushi MITSUGI
- Department of Chemistry, Faculty of Science, Kyushu University
| | | | - Kenta FUJII
- Department of Chemistry and Applied Chemistry, Faculty of Science and Engineering, Saga University
| | | |
Collapse
|
22
|
Smirnov PR, Trostin VN. Structures of the nearest surroundings of the K+, Rb+, and Cs+ ions in aqueous solutions of their salts. RUSS J GEN CHEM+ 2007. [DOI: 10.1134/s1070363207120043] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
23
|
Collins KD, Neilson GW, Enderby JE. Ions in water: Characterizing the forces that control chemical processes and biological structure. Biophys Chem 2007; 128:95-104. [PMID: 17418479 DOI: 10.1016/j.bpc.2007.03.009] [Citation(s) in RCA: 433] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 03/09/2007] [Accepted: 03/10/2007] [Indexed: 11/29/2022]
Abstract
The continuum electrostatics model of Debye and Hückel [P. Debye and E. Hückel, On the theory of electrolytes. I. Freezing point depression and related phenomena., Phys. Z. 24 (1923) 185-206.] and its successors utilize a macroscopic dielectric constant and assume that all interactions involving ions are strictly electrostatic, implying that simple ions in water generate electric fields strong enough to orient water dipoles over long distances. However, solution neutron and X-ray diffraction indicate that even di- and tri-valent ions do not significantly alter the density or orientation of water more than two water molecules (5 A) away. Therefore the long range electric fields (generated by simple ions) which can be detected by various resonance techniques such as fluorescence resonance energy transfer over distances of 30 A (about 11 water diameters) or more must be weak relative to the strength of water-water interactions. Two different techniques indicate that the interaction of water with anions is by an approximately linear hydrogen bond, suggesting that the dominant forces on ions in water are short range forces of a chemical nature.
Collapse
Affiliation(s)
- Kim D Collins
- Center of Marine Biotechnology and Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, MD 21201, USA.
| | | | | |
Collapse
|
24
|
Ansell S, Barnes AC, Mason PE, Neilson GW, Ramos S. X-ray and neutron scattering studies of the hydration structure of alkali ions in concentrated aqueous solutions. Biophys Chem 2006; 124:171-9. [PMID: 16815625 DOI: 10.1016/j.bpc.2006.04.018] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 04/28/2006] [Accepted: 04/29/2006] [Indexed: 11/23/2022]
Abstract
The presence of ions in water provides a rich and varied environment in which many natural processes occur with important consequences in biology, geology and chemistry. This article will focus on the structural properties of ions in water and it will be shown how the 'difference' methods of neutron diffraction with isotopic substitution (NDIS) and anomalous X-ray diffraction (AXD) can be used to obtain direct information regarding the radial pair distribution functions of many cations and anions in solution. This information can subsequently be used to calculate coordination numbers and to determine ion-water conformation in great detail. As well as enabling comparisons to be made amongst ions in particular groups in the periodic table, such information can also be contrasted with results provided by molecular dynamics (MD) simulation techniques. To illustrate the power of these 'difference' methods, reference will be made to the alkali group of ions, all of which have been successfully investigated by the above methods, with the exception of the radioactive element francium. Additional comments will be made on how NDIS measurements are currently being combined with MD simulations to determine the structure around complex ions and molecules, many of which are common in biological systems.
Collapse
Affiliation(s)
- S Ansell
- ISIS Division, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK
| | | | | | | | | |
Collapse
|