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McCarthy WP, Blais HN, O'Callaghan TF, Hossain M, Moloney M, Danaher M, O'Connor C, Tobin JT. Application of nanofiltration for the removal of chlorate from skim milk. Int Dairy J 2022. [DOI: 10.1016/j.idairyj.2022.105321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Herbert JM, Paul SK. Interaction Energy Analysis of Monovalent Inorganic Anions in Bulk Water Versus Air/Water Interface. Molecules 2021; 26:6719. [PMID: 34771133 PMCID: PMC8588468 DOI: 10.3390/molecules26216719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 10/29/2021] [Accepted: 11/03/2021] [Indexed: 11/16/2022] Open
Abstract
Soft anions exhibit surface activity at the air/water interface that can be probed using surface-sensitive vibrational spectroscopy, but the structural implications of this surface activity remain a matter of debate. Here, we examine the nature of anion-water interactions at the air/water interface using a combination of molecular dynamics simulations and quantum-mechanical energy decomposition analysis based on symmetry-adapted perturbation theory. Results are presented for a set of monovalent anions, including Cl-, Br-, I-, CN-, OCN-, SCN-, NO2-, NO3-, and ClOn- (n=1,2,3,4), several of which are archetypal examples of surface-active species. In all cases, we find that average anion-water interaction energies are systematically larger in bulk water although the difference (with respect to the same quantity computed in the interfacial environment) is well within the magnitude of the instantaneous fluctuations. Specifically for the surface-active species Br-(aq), I-(aq), ClO4-(aq), and SCN-(aq), and also for ClO-(aq), the charge-transfer (CT) energy is found to be larger at the interface than it is in bulk water, by an amount that is greater than the standard deviation of the fluctuations. The Cl-(aq) ion has a slightly larger CT energy at the interface, but NO3-(aq) does not; these two species are borderline cases where consensus is lacking regarding their surface activity. However, CT stabilization amounts to <20% of the total induction energy for each of the ions considered here, and CT-free polarization energies are systematically larger in bulk water in all cases. As such, the role of these effects in the surface activity of soft anions remains unclear. This analysis complements our recent work suggesting that the short-range solvation structure around these ions is scarcely different at the air/water interface from what it is in bulk water. Together, these observations suggest that changes in first-shell hydration structure around soft anions cannot explain observed surface activities.
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Affiliation(s)
- John M. Herbert
- Department of Chemistry & Biochemistry, The Ohio State University, Columbus, OH 43210, USA;
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Yadav S, Chandra A. Solvation Shell of the Nitrite Ion in Water: An Ab Initio Molecular Dynamics Study. J Phys Chem B 2020; 124:7194-7204. [PMID: 32706258 DOI: 10.1021/acs.jpcb.0c02221] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We performed ab initio molecular dynamics simulation of a nitrite ion in water to investigate the structural and dynamical properties of its hydration shell. The nitrite ion is found to exhibit strong asymmetry toward hydrogen bonding due to its two different types of hydrogen bond acceptor sites. This difference is better captured through further partitioning of the hydration shell into its proximal and distal regions. The frequency shifts of the stretch modes of hydration shell water reveal that the nitrogen site forms a stronger hydrogen bond than its oxygen sites with the latter forming hydrogen bonds, which are similar in strength to that between a pair of water molecules. The escape dynamics of water from the hydration shell is found to be rather slow, which seems to classify the nitrite ion as a structure-maker. However, the dynamics of orientational and hydrogen bond relaxation reveal a faster mobility of water molecules in the hydration shell than bulk water in spite of strong ion-water interactions. It is found that the nitrite ion can hold water molecules in its solvation shell and still make them rotate fast in its vicinity through switching of their hydrogen bonds between its nitrogen and oxygen acceptor sites. The dipole moment of the solute in water is also calculated in the present study.
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Affiliation(s)
- Sushma Yadav
- Department of Chemistry, Indian Institute of Technology Kanpur, 208016 Kanpur, India
| | - Amalendu Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur, 208016 Kanpur, India
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Borah S. Spatially resolved hydration shells and dynamics of different sulfur species in water from first-principle molecular dynamics simulations. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Borah S. Hydration Properties of H nPO 4n-3 (n = 0-3) From Ab Initio Molecular Dynamics Simulations. J Phys Chem B 2020; 124:5454-5464. [PMID: 32484352 DOI: 10.1021/acs.jpcb.0c01769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
For a comprehensive and detailed microscopic understanding of the hydration properties of primary aqueous phosphorus species of valence states V (viz., H3PO4, H2PO4-, HPO42-, and PO43-), a series of extensive ab initio molecular dynamics simulations is conducted at ambient temperature. In each of these cases, the spatially resolved, three-dimensional hydration shells are computed, allowing for a direct microscopic visual understanding of the hydration shells around the species. Since these species are excellent agents for the formation of hydrogen bonds (H-bonds) in water, which determine a wide range of their structural, dynamic, and spectroscopic features, a detailed analysis of the qualitative and quantitative aspects of the H-bonds, including their lifetime calculations, is performed. Vibrational density of states (VDOS) is calculated for each of the species in solute phases, resolved for each H-bonding site, and compared against the gas-phase normal modes of H3PO4 for the purpose of understanding the signatures of the peaks in VDOS plots and, in particular, the effects of solvation and H-bonding mechanisms. The results are well in line with available experimental data and other recent computer-aided studies in the literature.
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Affiliation(s)
- Sangkha Borah
- Okinawa Institute of Science and Technology Graduate University, 1919-1, Okinawa 904-0412, Japan.,Department of Physics, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
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Abstract
The strength of hydrogen bonding to and structure of hydrated oxometallate ions in aqueous solution have been studied by double difference infrared (DDIR) spectroscopy and large-angle X-ray scattering (LAXS), respectively. Anions are hydrated by accepting hydrogen bonds from the hydrating water molecules. The oxygen atom of the permanganate and perrhenate ions form weaker and longer hydrogen bonds to water than the hydrogen bonds in bulk water (i.e., they act as structure breakers), while the oxygen atoms of the chromate, dichromate, molybdate, tungstate, and hydrogenvanadate ions form hydrogen bonds stronger than those in bulk water (i.e., they act as structure makers). The oxometallate ions form one hydration shell distinguishable from bulk water as determined by DDIR spectroscopy and LAXS. The hydration of oxoanions results in X-O bond distances ca. 0.02 Å longer than those in unsolvated ions in the solid state not involved in strong bonding to counterions. The oxygens of oxoanions with a central atom from the second and third series in the periodic table and the hydrogenvanadate ion hydrogen bind three hydrating water molecules, while oxygens of oxoanions with a heavier central atom only form hydrogen bonds to two water molecules.
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Affiliation(s)
- Maciej Śmiechowski
- Department of Physical Chemistry, Chemical Faculty, Gdańsk University of Technology, ul. Gabriela Narutowicza 11/12, PL-80-233 Gdańsk, Poland
| | - Ingmar Persson
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden
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Sharma B, Chandra A. Dynamics of Water in the Solvation Shell of an Iodate Ion: A Born-Oppenheimer Molecular Dynamics Study. J Phys Chem B 2020; 124:2618-2631. [PMID: 32150681 DOI: 10.1021/acs.jpcb.9b12008] [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
The iodate ion has an anisotropic structure and charge distribution. It has a pyramidal shape with the iodine atom located at the peak of the pyramid. The water molecules interact differently with the positively charged iodine and the negatively charged oxygen atoms of this anion, giving rise to two distinct solvation shells. In the present study, we have performed ab initio Born-Oppenheimer molecular dynamics simulations to investigate the dynamics of water molecules in the iodine and oxygen solvation shells of the iodate ion and compared the behavior with those of the bulk. The dynamics of water is calculated for both the BLYP and the dispersion-corrected BLYP-D3 functionals at room temperature. The dynamics of water in the solvation shells at higher temperatures of 353 and 330 K has also been investigated for the BLYP and BLYP-D3 functionals, respectively. The hydrogen bond dynamics, vibrational spectral diffusion, orientational and translational diffusion, and residence dynamics of water molecules in the two solvation shells are looked at in the current study. The ion-water hydrogen bond dynamics is found to be somewhat faster than that for water-water hydrogen bonds in the bulk, which can be attributed to a ring-like electron distribution on the iodate oxygens. The dynamical trends are connected to the water structure making/breaking properties of the positively charged iodine and negatively charged oxygen sites of the anion. Furthermore, orientational jumps of the iodate ion and also those of surrounding water molecules which are hydrogen bonded to the oxygen atoms of the iodate ion are also investigated. It is found that the nature of these orientational jumps can be different from those reported earlier for planar polyoxyanions such as the nitrate ion.
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Affiliation(s)
- Bikramjit Sharma
- Department of Chemistry, Indian Institute of Technology Kanpur 208016, India
| | - Amalendu Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur 208016, India
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Busca G, Gervasini A. Solid acids, surface acidity and heterogeneous acid catalysis. ADVANCES IN CATALYSIS 2020. [DOI: 10.1016/bs.acat.2020.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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10
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Song F, Al-Ameed K, Schilling M, Fox T, Luber S, Patzke GR. Mechanistically Driven Control over Cubane Oxo Cluster Catalysts. J Am Chem Soc 2019; 141:8846-8857. [PMID: 31120246 DOI: 10.1021/jacs.9b01356] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Predictive and mechanistically driven access to polynuclear oxo clusters and related materials remains a grand challenge of inorganic chemistry. We here introduce a novel strategy for synthetic control over highly sought-after transition metal {M4O4} cubanes. They attract interest as molecular water oxidation catalysts that combine features of both heterogeneous oxide catalysts and nature's cuboidal {CaMn4O5} center of photosystem II. For the first time, we demonstrate the outstanding structure-directing effect of straightforward inorganic counteranions in solution on the self-assembly of oxo clusters. We introduce a selective counteranion toolbox for the controlled assembly of di(2-pyridyl) ketone (dpk) with M(OAc)2 (M = Co, Ni) precursors into different cubane types. Perchlorate anions provide selective access to type 2 cubanes with the characteristic {H2O-M2(OR)2-OH2} edge-site, such as [Co4(dpy-C{OH}O)4(OAc)2(H2O)2](ClO4)2. Type 1 cubanes with separated polar faces [Co4(dpy-C{OH}O)4(L2)4] n+ (L2 = OAc, Cl, or OAc and H2O) can be tuned with a wide range of other counteranions. The combination of these counteranion sets with Ni(OAc)2 as precursor selectively produces type 2 Co/Ni-mixed or {Ni4O4} cubanes. Systematic mechanistic experiments in combination with computational studies provide strong evidence for type 2 cubane formation through reaction of the key dimeric building block [M2(dpy-C{OH}O)2(H2O)4]2+ with monomers, such as [Co(dpy-C{OH}O)(OAc)(H2O)3]. Furthermore, both experiments and DFT calculations support an energetically favorable type 1 cubane formation pathway via direct head-to-head combination of two [Co2(dpy-C{OH}O)2(OAc)2(H2O)2] dimers. Finally, the visible-light-driven water oxidation activity of type 1 and 2 cubanes with tuned ligand environments was assessed. We pave the way to efficient design concepts in coordination chemistry through ionic control over cluster assembly pathways. Our comprehensive strategy demonstrates how retrosynthetic analyses can be implemented with readily available assembly directing counteranions to provide rapid access to tuned molecular materials.
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Affiliation(s)
- Fangyuan Song
- Department of Chemistry , University of Zurich , Winterthurerstrasse 190 , CH-8057 Zurich , Switzerland
| | - Karrar Al-Ameed
- Department of Chemistry , University of Zurich , Winterthurerstrasse 190 , CH-8057 Zurich , Switzerland.,Faculty of Science , University of Kufa , 54001 Najaf , Iraq
| | - Mauro Schilling
- Department of Chemistry , University of Zurich , Winterthurerstrasse 190 , CH-8057 Zurich , Switzerland
| | - Thomas Fox
- Department of Chemistry , University of Zurich , Winterthurerstrasse 190 , CH-8057 Zurich , Switzerland
| | - Sandra Luber
- Department of Chemistry , University of Zurich , Winterthurerstrasse 190 , CH-8057 Zurich , Switzerland
| | - Greta R Patzke
- Department of Chemistry , University of Zurich , Winterthurerstrasse 190 , CH-8057 Zurich , Switzerland
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Bogachev NA, Gorbunov AO, Skripkin MY, Nikol’skii AB. A Solution-Solid Phase Equilibrium in Ternary Systems Containing d-Elements Salts and Mixed Oxygen-Donor Solvent. RUSS J GEN CHEM+ 2019. [DOI: 10.1134/s1070363219060082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Prasetyo N, Hünenberger PH, Hofer TS. Single-Ion Thermodynamics from First Principles: Calculation of the Absolute Hydration Free Energy and Single-Electrode Potential of Aqueous Li + Using ab Initio Quantum Mechanical/Molecular Mechanical Molecular Dynamics Simulations. J Chem Theory Comput 2018; 14:6443-6459. [PMID: 30284829 DOI: 10.1021/acs.jctc.8b00729] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A recently proposed thermodynamic integration (TI) approach formulated in the framework of quantum mechanical/molecular mechanical molecular dynamics (QM/MM MD) simulations is applied to study the structure, dynamics, and absolute intrinsic hydration free energy Δs GM+,wat◦ of the Li+ ion at a correlated ab initio level of theory. Based on the results, standard values (298.15 K, ideal gas at 1 bar, ideal solute at 1 molal) for the absolute intrinsic hydration free energy [Formula: see text] of the proton, the surface electric potential jump χwat◦ upon entering bulk water, and the absolute single-electrode potential [Formula: see text] of the reference hydrogen electrode are calculated to be -1099.9 ± 4.2 kJ·mol-1, 0.13 ± 0.08 V, and 4.28 ± 0.04 V, respectively, in excellent agreement with the standard values recommended by Hünenberger and Reif on the basis of an extensive evaluation of the available experimental data (-1100 ± 5 kJ·mol-1, 0.13 ± 0.10 V, and 4.28 ± 0.13 V). The simulation results for Li+ are also compared to those for Na+ and K+ from a previous study in terms of relative hydration free energies ΔΔs GM+,wat◦ and relative electrode potentials [Formula: see text]. The calculated values are found to agree extremely well with the experimental differences in standard conventional hydration free energies ΔΔs GM+,wat• and redox potentials [Formula: see text]. The level of agreement between simulation and experiment, which is quantitative within error bars, underlines the substantial accuracy improvement achieved by applying a highly demanding QM/MM approach at the resolution-of-identity second-order Møller-Plesset perturbation (RIMP2) level over calculations relying on purely molecular mechanical or density functional theory (DFT) descriptions. A detailed analysis of the structural and dynamical properties of the Li+ hydrate indicates that a correct description of the solvation structure and dynamics is achieved as well at this level of theory. Consideration of the QM/MM potential-energy components also shows that the partitioning into QM and MM zones does not induce any significant energetic artifact for the system considered.
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Affiliation(s)
- Niko Prasetyo
- Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry , University of Innsbruck , Innrain 80-82 , A-6020 Innsbruck , Austria.,Austria-Indonesia Centre (AIC) for Computational Chemistry , Universitas Gadjah Mada , Sekip Utara , Yogyakarta 55281 , Indonesia.,Department of Chemistry, Faculty of Mathematics and Natural Sciences , Universitas Gadjah Mada , Sekip Utara , Yogyakarta 55281 , Indonesia
| | - Philippe H Hünenberger
- Laboratorium für Physikalische Chemie , ETH Zürich, ETH-Hönggerberg , HCI Building , CH-8093 Zürich , Switzerland
| | - Thomas S Hofer
- Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry , University of Innsbruck , Innrain 80-82 , A-6020 Innsbruck , Austria
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Persson I, Trublet M, Klysubun W. Structure Determination of Phosphoric Acid and Phosphate Ions in Aqueous Solution Using EXAFS Spectroscopy and Large Angle X-ray Scattering. J Phys Chem A 2018; 122:7413-7420. [PMID: 30156411 DOI: 10.1021/acs.jpca.8b05641] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The structures of hydrated phosphoric acid and phosphate ions (H2PO4-, HPO42-, and PO43-) in aqueous solution have been determined by P K-edge EXAFS and large angle X-ray scattering (LAXS). The P-O bond distance in all phosphate species studied is close to 1.53 Å. The P-(O)···Oaq distances have been refined to ca. 3.6 Å from the LAXS data giving a P-O···Oaq bond angle close to tetrahedral, suggesting that each oxygen or OH group of phosphoric acid and dihydrogen phosphate, on average, hydrogen bind three water molecules. The (P-)O(-H)···Oaq and (P-)O···(H-)Oaq hydrogen bonds in hydrated phosphoric acid and the H2PO4- ion are shorter than the hydrogen bonds in neat water. This supports previous infrared spectroscopic studies claiming that the hydrogen bonds in hydrated phosphoric acid and phosphate ions are stronger than the hydrogen bonds in neat water. Phosphoric acid and phosphate ions can therefore be regarded as structure making solutes. This is the first study applying transmission mode X-ray absorption spectroscopy (XAS) data collection on the P K-edge. It shows that XAS spectra collected in transmission mode have a much better S/N ratio than data collected in fluorescence mode, allowing accurate determination of P-O bond distances. Furthermore, P K-edge EXAFS data collected in fluorescence mode display a higher amplitude at high k than expected due to increasing radiated volume of the sample with increasing energy as the total absorption decreases sharply with increasing energy of the X-rays. As a result, the fluorescence signal becomes nonproportional to the intensity of the X-ray beam over the EXAFS spectrum. This results in an increasing amplitude of the EXAFS function with increasing energy of the X-ray beam resulting in too small Debye-Waller coefficients.
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Affiliation(s)
- Ingmar Persson
- Department of Molecular Sciences , Swedish University of Agricultural Sciences , P.O.Box 7015, SE-750 07 Uppsala , Sweden
| | - Mylène Trublet
- Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering , Luleå University of Technology , SE-971 87 Luleå , Sweden
| | - Wantana Klysubun
- Synchrotron Light Research Institute , 111 Moo 6, University Avenue , Muang , Nakhon Ratchasima 30000 , Thailand
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Sharma B, Chandra A. Born-Oppenheimer Molecular Dynamics Simulations of a Bromate Ion in Water Reveal Its Dual Kosmotropic and Chaotropic Behavior. J Phys Chem B 2018; 122:2090-2101. [PMID: 29376361 DOI: 10.1021/acs.jpcb.7b09300] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The solvation structure and dynamics of a bromate (BrO3-) ion in water are studied by means of Born-Oppenheimer molecular dynamics simulations at two different temperatures using the Becke-Lee-Yang-Parr functional with Grimme D3 dispersion corrections. The bromate ion possesses a pyramidal structure, and it has two types of solvation sites, namely, the bromine and oxygen atoms. We have looked at different radial and orientational distributions of water molecules around the bromate ion and also investigated their hydrogen bonding properties. The solvation structure of the bromate ion is also compared with that of the iodate (IO3-) ion, which is structurally rather similar to the bromate ion and was found to have some unusual solvation properties in water. It is found that the bromate ion follows a similar trend as that followed by the iodate ion as far as the solvation structure is concerned. However, the effect of the former on surrounding water is found to be much weaker than that of the latter. On the dynamical side, we have looked at diffusion, residence dynamics, and also the orientational and hydrogen bond relaxation of water molecules around the BrO3- ion and compared them with those of the bulk. Dynamical results are presented for both H2O and D2O around the BrO3- ion. Interpretation of the dynamical results in terms of structure-making (kosmotropic)/-breaking (chaotropic) properties of the BrO3- ion reveals that the bromine atom of this ion acts as a water structure breaker, whereas the three oxygens act as water structure makers. Thus, in spite of being a single ion, the bromate ion has dual characteristics and the experimentally observed kosmotropic ability of this ion is actually a trade-off between a chaotropic site (the bromine atom) and three kosmotropic sites (three oxygen atoms) that are present in the ion.
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Affiliation(s)
- Bikramjit Sharma
- Department of Chemistry, Indian Institute of Technology Kanpur , Kanpur 208016, India
| | - Amalendu Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur , Kanpur 208016, India
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