1
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Biswas B, Allen HC. Solution and Surface Solvation of Nitrate Anions with Iron(III) and Aluminum(III) in Aqueous Environments: A Raman and Vibrational Sum Frequency Generation Study. J Phys Chem A 2024. [PMID: 39370705 DOI: 10.1021/acs.jpca.4c05142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/08/2024]
Abstract
Hydrated trivalent metal nitrate salts, Fe(NO3)3·9H2O and Al(NO3)3·9H2O, in both solid and aqueous phases are investigated. Raman and surface-selective vibrational sum frequency generation (SFG) spectroscopy, are used to shed light on ion-ion interactions and hydration in several spectral regions spanning low frequency (440-550 cm-1) to higher frequency modes of nitrate and water (720, 1050, 1250-1450, and 2800-3750 cm-1). These frequencies span the metal-water mode, nitrate in-plane deformation, nitrate symmetric and asymmetric modes, and the OH stretch of condensed phase water molecules. Comparison to NaNO3, and in some cases KNO3, is also shown, providing insight. Splitting and frequency shifts are observed and discussed for both the solid state and solution phase. The Lewis acidity of Fe3+ and Al3+ ions plays a significant role in the observed spectra, in particular for the nitrate asymmetric band splitting and frequency shift. The spectral response from water solvation for iron and aluminum nitrates is nonlinear as compared to linear for sodium nitrate, suggesting significantly different solvation environments that are limited by water hydration capacity at higher concentrations. Moreover, a non-hydrogen bonded OH, dangling OH, from hydrating water molecules is observed spectroscopically for Al and Fe nitrate solutions. Furthermore, aluminum nitrate perturbs the surface water structure more than iron nitrate despite aluminum being a weaker Lewis acid. The surface water structure is thus found to be unique for the Al(NO3)3 solutions as compared to both Fe(NO3)3 and NaNO3, such that surface solvation is more pronounced. This observation exemplifies the nature of the Fe(III) and Al(III) ions and their substantial influence on the surface water structure.
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Affiliation(s)
- Biswajit Biswas
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Heather C Allen
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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2
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Kawai Y, Yamamoto Y, Kiyohara K. Selective adsorption of divalent and trivalent cations in porous electrodes. J Chem Phys 2024; 161:094701. [PMID: 39225524 DOI: 10.1063/5.0222272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Accepted: 08/19/2024] [Indexed: 09/04/2024] Open
Abstract
The capacitive deionization technology uses the electrochemical adsorption of ions in porous electrodes to desalinate seawater or brackish water. Recently, capacitive deionization has gained significant attention as a technology for selective adsorption of ionic species from multicomponent aqueous electrolytes. To investigate the mechanism of selective adsorption at the molecular level, we performed molecular dynamics simulations of aqueous electrolytes and porous electrodes with different divalent or trivalent ions, electrode pore sizes, and applied voltages. We calculated the free energy barriers preventing ions from entering the pores of the electrode and the structure of the water molecules near the ions and the electrode surface under various conditions. Our results suggest that, when the pore and ion sizes are comparable, the steric and electrostatic interactions between the hydrated ions and electrode pores are comparable in magnitude. Moreover, the relative importance of the two interactions can be reversed by slight changes in the external conditions, such as the ion size, valence of the ions, electrode pore size, and applied voltage. Thus, by finely tuning the electrode pore size and the applied voltage, it may be possible to selectively adsorb a particular ionic species from a multicomponent electrolyte through capacitive deionization using a porous electrode.
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Affiliation(s)
- Yusuke Kawai
- Department of Chemistry, Graduate School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan
| | - Yuji Yamamoto
- Department of Chemistry, Graduate School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan
| | - Kenji Kiyohara
- Department of Chemistry, Graduate School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan
- Research Institute of Electrochemical Energy, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka 563-8577, Japan
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3
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Ming X, Si W, Yu Q, Sun Z, Qiu G, Cao M, Li Y, Li Z. Molecular insight into the initial hydration of tricalcium aluminate. Nat Commun 2024; 15:2929. [PMID: 38575602 PMCID: PMC10995194 DOI: 10.1038/s41467-024-47164-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 03/21/2024] [Indexed: 04/06/2024] Open
Abstract
Portland cement (PC) is ubiquitously used in construction for centuries, yet the elucidation of its early-age hydration remains a challenge. Understanding the initial hydration progress of tricalcium aluminate (C3A) at molecular scale is thus crucial for tackling this challenge as it exhibits a proclivity for early-stage hydration and plays a pivotal role in structural build-up of cement colloids. Herein, we implement a series of ab-initio calculations to probe the intricate molecular interactions of C3A during its initial hydration process. The C3A surface exhibits remarkable chemical activity in promoting water dissociation, which in turn facilitates the gradual desorption of Ca ions through a metal-proton exchange reaction. The dissolution pathways and free energies of these Ca ions follow the ligand-exchange mechanism with multiple sequential reactions to form the ultimate products where Ca ions adopt fivefold or sixfold coordination. Finally, these Ca complexes reprecipitate on the remaining Al-rich layer through the interface-coupled dissolution-reprecipitation mechanism, demonstrating dynamically stable inner-sphere adsorption states. The above results are helpful in unmasking the early-age hydration of PC and advancing the rational design of cement-based materials through the bottom-up approach.
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Affiliation(s)
- Xing Ming
- Faculty of Innovation Engineering, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macao SAR, China
| | - Wen Si
- School of Civil Engineering, Dalian University of Technology, Dalian, China
| | - Qinglu Yu
- Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macao SAR, China
| | - Zhaoyang Sun
- Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macao SAR, China
| | - Guotao Qiu
- Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macao SAR, China
| | - Mingli Cao
- School of Civil Engineering, Dalian University of Technology, Dalian, China
| | - Yunjian Li
- Faculty of Innovation Engineering, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macao SAR, China.
| | - Zongjin Li
- Faculty of Innovation Engineering, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macao SAR, China.
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Fuhrman Javitt L, Kalita S, Dubey KD, Ehre D, Shaik S, Lahav M, Lubomirsky I. Electro-Freezing of Supercooled Water Is Induced by Hydrated Al 3+ and Mg 2+ Ions: Experimental and Theoretical Studies. J Am Chem Soc 2023; 145:18904-18911. [PMID: 37602827 PMCID: PMC10472506 DOI: 10.1021/jacs.3c05004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Indexed: 08/22/2023]
Abstract
This work reports that the octahedral hydrated Al3+ and Mg2+ ions operate within electrolytic cells as kosmotropic (long-range order-making) "ice makers" of supercooled water (SCW). 10-5 M solutions of hydrated Al3+ and Mg2+ ions each trigger, near the cathode (-20 ± 5 V), electro-freezing of SCW at -4 °C. The hydrated Al3+ ions do so with 100% efficiency, whereas the Mg2+ ions induce icing with 40% efficiency. In contrast, hydrated Na+ ions, under the same experimental conditions, do not induce icing differently than pure water. As such, our study shows that the role played by Al3+ and Mg2+ ions in water electro-freezing is impacted by two synchronous effects: (1) a geometric effect due to the octahedral packing of the coordinated water molecules around the metallic ions, and (2) the degree of polarization which these two ions induce and thereby acidify the coordinated water molecules, which in turn imparts them with an ice-like structure. Long-duration molecular dynamics (MD) simulations of the Al3+ and Mg2+ indeed reveal the formation of "ice-like" hexagons in the vicinity of these ions. Furthermore, the MD shows that these hexagons and the electric fields of the coordinate water molecules give rise to ultimate icing. As such, the MD simulations provide a rational explanation for the order-making properties of these ions during electro-freezing.
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Affiliation(s)
- Leah Fuhrman Javitt
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Surajit Kalita
- Institute
of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Kshatresh Dutta Dubey
- Department
of Chemistry, School of Natural Sciences, Shiv Nadar Institution of Eminence, Greater Noida, Uttar Pradesh 201314, India
| | - David Ehre
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sason Shaik
- Institute
of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Meir Lahav
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Igor Lubomirsky
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
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5
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Xian Y, Wang B, Lin Z. Ti 3 C 2 T x MXene with High Pseudocapacitive Activity and Large Potential Window in a Mild AlCl 3 Aqueous Electrolyte. SMALL METHODS 2023; 7:e2201526. [PMID: 37052537 DOI: 10.1002/smtd.202201526] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 12/19/2022] [Indexed: 06/19/2023]
Abstract
MXenes have been extensively explored as supercapacitor electrodes, especially in acidic aqueous electrolytes, where ultrahigh specific capacitance can be achieved; however, their narrow working potential window (≤ 1.0 V) limits the acquisition of high energy. Neutral and alkaline electrolytes can be used to extend the working potential window but MXenes in these electrolytes are less pseudocapacitive active, which leads to reduced charge storage. In this study, it is shown that Ti3 C2 Tx MXene in a mild AlCl3 aqueous electrolyte can operate at a wide potential range from 0 to -1.3 V versus Hg/Hg2 SO4 and retain high pseudocapacitive activity. Thus, a high capacity of up to 85 mAh g-1 is achieved, surpassing its performance in H2 SO4 electrolyte of 78 mAh g-1 . More interestingly, most of the capacity is released at a more negative potential range than that in acidic electrolytes, making it more suitable as a negative electrode material. In situ electrochemical quartz crystal microbalance results suggest that the high capacity originates from the pseudocapacitive intercalation/deintercalation of H+ instead of Al3+ , providing the possibility of coupling MXene anodes with proton redox active cathodes to achieve high-energy and high-power devices.
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Affiliation(s)
- Yongqiu Xian
- College of Materials Science and Engineering, Sichuan University, Chengdu, Sichuan, 610065, P. R. China
| | - Bin Wang
- College of Materials Science and Engineering, Sichuan University, Chengdu, Sichuan, 610065, P. R. China
| | - Zifeng Lin
- College of Materials Science and Engineering, Sichuan University, Chengdu, Sichuan, 610065, P. R. China
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Prange MP, Mergelsberg ST, Kerisit SN. Structural water in amorphous carbonate minerals: ab initio molecular dynamics simulations of X-ray pair distribution experiments. Phys Chem Chem Phys 2023; 25:6768-6779. [PMID: 36789518 DOI: 10.1039/d2cp04881g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Water is known to play a controlling role in directing mineralization pathways and stabilizing metastable amorphous intermediates in hydrous carbonate mineral MCO3·nH2O systems, where M2+ is a divalent metal cation. Despite this recognition, the nature of the controls on crystallization is poorly understood, largely owing to the difficulty in characterizing the dynamically disordered structures of amorphous intermediates at the atomic scale. Here, we present a series of atomistic models, derived from ab initio molecular dynamics simulation, across a range of experimentally relevant cations (M = Ca, Mg, Sr) and hydration levels (0 ≤ n ≤ 2). Theoretical simulations of the dependence of the X-ray pair distribution function on the hydration level n show good agreement with available experimental data and thus provide further evidence for a lack of significant nanoscale structure in amorphous carbonates. Upon dehydration, the metal coordination number does not change significantly, but the relative extent of water dissociation increases, indicating that a thermodynamic driving force exists for water dissociation to accompany dehydration. Mg strongly favors monodentate conformation of carbonate ligands and shows a marked preference to exchange monodentate carbonate O for water O upon hydration, whereas Ca and Sr exchange mono- and bidentate carbonate ligands with comparable frequency. Water forms an extensive hydrogen bond network among both water and carbonate groups that exhibits frequent proton transfers for all three cations considered suggesting that proton mobility is likely predominantly due to water dissociation and proton transfer reactions rather than molecular water diffusion.
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Affiliation(s)
- Micah P Prange
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington, 99352, USA.
| | - Sebastian T Mergelsberg
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington, 99352, USA.
| | - Sebastien N Kerisit
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington, 99352, USA.
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7
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Messias A, Santos DES, Pontes FJS, Soares TA. The tug of war between Al 3+ and Na + for order-disorder transitions in lipid-A membranes. Phys Chem Chem Phys 2021; 23:15127-15137. [PMID: 34254086 DOI: 10.1039/d1cp02173g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cations play a critical role in the stability and morphology of lipid-A aggregates by neutralizing, hydrating and cross-linking these glycolipid molecules. Monophosphorylated lipid-A is the major immunostimulatory principle in commercially available adjuvants containing Al3+ such as adjuvant system 04 (AS04). The antagonist/agonist immunomodulatory properties of lipid-A are associated with chemical variations (e.g. the number of acyl chains and phosphate groups) and their aggregate arrangements (e.g. lamellar, nonlamellar or mixed). Therefore, the identification of the active form of lipid-A can provide valuable guidance in the development of vaccine adjuvants capable of boosting the immune system with decreased reactogenicity. Although the effect of mono and divalent cations on the structural polymorphism and endotoxicity of LPS has been previously investigated, much less is known about the effect of trivalent cations. We have investigated the effect of NaCl and AlCl3 salt solutions on the structural dynamics and stability of mono and diphosphorylated lipid-A membranes via atomistic MD simulations. The Al3+ ion exerts two major effects on the structural dynamics of lipid-A membranes. It acts as an efficient cross-linker of mono or diphosphorylated lipid-A molecules, thus stabilizing the lamellar arrangement of these glycolipids. It also alters the lipid-A packing and membrane fluidity, inducing disorder → order structural transitions of the membrane. This effect is promptly reversed upon the addition of NaCl solution, which promotes a nearly threefold increase in the amount of water in the carbohydrate moiety of the Al3+-containing lipid-A membranes. The exchange dynamics and residence times of cation-coordinated water molecules in these membranes provide insights into the molecular mechanism for the Na+-induced transition from a densely packed ordered phase to a disordered one. Al3+ counter-ions favor ordered lamellar aggregates, which has been previously associated with the lack of endotoxic activity and cytokine-inducing action. The resulting microscopic understanding of the structure and dynamics of lipid-A aggregates in the presence of Al3+ and Na+ salts can provide valuable guidance in the development of vaccine adjuvants capable of boosting the immune system with decreased reactogenicity.
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Affiliation(s)
- Andresa Messias
- Department of Fundamental Chemistry, Universidade Federal de Pernambuco, 50740-560 Recife, Brazil.
| | - Denys E S Santos
- Department of Fundamental Chemistry, Universidade Federal de Pernambuco, 50740-560 Recife, Brazil.
| | - Frederico J S Pontes
- Department of Fundamental Chemistry, Universidade Federal de Pernambuco, 50740-560 Recife, Brazil.
| | - Thereza A Soares
- Department of Fundamental Chemistry, Universidade Federal de Pernambuco, 50740-560 Recife, Brazil. and Instituto de Fisica, Universidade de São Paulo, 05508-090 São Paulo, Brazil
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8
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Ye X, Capezza AJ, Xiao X, Lendel C, Hedenqvist MS, Kessler VG, Olsson RT. Protein Nanofibrils and Their Hydrogel Formation with Metal Ions. ACS NANO 2021; 15:5341-5354. [PMID: 33666436 PMCID: PMC8041371 DOI: 10.1021/acsnano.0c10893] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/26/2021] [Indexed: 06/12/2023]
Abstract
Protein nanofibrils (PNFs) have been prepared by whey protein fibrillation at low pH and in the presence of different metal ions. The effect of the metal ions was systematically studied both in terms of PNF suspension gelation behavior and fibrillation kinetics. A high valence state and a small ionic radius (e.g., Sn4+) of the metal ion resulted in the formation of hydrogels already at a metal ion concentration of 30 mM, whereas an intermediate valence state and larger ionic radius (Co2+, Ni2+, Al3+) resulted in the hydrogel formation occurring at 60 mM. A concentration of 120 mM of Na+ was needed to form a PNF hydrogel, while lower concentrations showed liquid behaviors similar to the reference PNF solution where no metal ions had been introduced. The hydrogel mechanics were investigated at steady-state conditions after 24 h of incubation/gelation, revealing that more acidic (smaller and more charged) metal ions induced ca. 2 orders of magnitude higher storage modulus as compared to the less acidic metal ions (with smaller charge and larger radius) for the same concentration of metal ions. The viscoelastic nature of the hydrogels was attributed to the ability of the metal ions to coordinate water molecules in the vicinity of the PNFs. The presence of metal ions in the solutions during the growth of the PNFs typically resulted in curved fibrils, whereas an upper limit of the concentration existed when oxides/hydroxides were formed, and the hydrogels lost their gel properties due to phase separation. Thioflavin T (ThT) fluorescence was used to determine the rate of the fibrillation to form 50% of the total PNFs (t1/2), which decreased from 2.3 to ca. 0.5 h depending on the specific metal ions added.
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Affiliation(s)
- Xinchen Ye
- Department
of Fibre and Polymer Technology, School of Engineering Sciences in
Chemistry, Biotechnology and Health, KTH
Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Antonio J. Capezza
- Department
of Fibre and Polymer Technology, School of Engineering Sciences in
Chemistry, Biotechnology and Health, KTH
Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Xiong Xiao
- Department
of Fibre and Polymer Technology, School of Engineering Sciences in
Chemistry, Biotechnology and Health, KTH
Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Christofer Lendel
- Department
of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology,
and Health, KTH Royal Institute of Technology, Stockholm SE-100 44, Sweden
| | - Mikael S. Hedenqvist
- Department
of Fibre and Polymer Technology, School of Engineering Sciences in
Chemistry, Biotechnology and Health, KTH
Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Vadim G. Kessler
- Department
of Molecular Sciences, Swedish University
of Agricultural Sciences, Box 7015, 750 07 Uppsala, Sweden
| | - Richard T. Olsson
- Department
of Fibre and Polymer Technology, School of Engineering Sciences in
Chemistry, Biotechnology and Health, KTH
Royal Institute of Technology, SE-100 44 Stockholm, Sweden
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9
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Smirnov PR, Grechin OV. Structure of the Nearest Environment of Ions in Aqueous Solutions of Aluminum Chloride According to X-ray Diffraction. RUSS J INORG CHEM+ 2018. [DOI: 10.1134/s0036023618090206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Zhang Q, Pan Z, Zhang L, Zhang R, Chen Z, Jin T, Wu T, Chen X, Zhuang W. Ion effect on the dynamics of water hydrogen bonding network: A theoretical and computational spectroscopy point of view. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2018. [DOI: 10.1002/wcms.1373] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Qiang Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
- Department of ChemistryBohai UniversityJinzhouChina
| | - Zhijun Pan
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Lu Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Ruiting Zhang
- School of Physics and Optoelectronic EngineeringXidian UniversityXi'anChina
| | - Zhening Chen
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Tan Jin
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Tianmin Wu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Xian Chen
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Wei Zhuang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
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Liu L, Zhang J, Dong S, Zhang F, Wang Y, Bi S. Density functional theory studies on the solvent effects in Al(H 2O) 63+ water-exchange reactions: the number and arrangement of outer-sphere water molecules. Phys Chem Chem Phys 2018; 20:7342-7350. [PMID: 29485659 DOI: 10.1039/c7cp07311a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Density functional theory (DFT) calculations combined with cluster models are performed at the B3LYP/6-311+G(d,p) level for investigating the solvent effects in Al(H2O)63+ water-exchange reactions. A "One-by-one" method is proposed to obtain the most representative number and arrangement of explicit H2Os in the second hydration sphere. First, all the possible ways to locate one explicit H2O in second sphere (Nm' = 1) based on the gas phase structure (Nm' = 0) are examined, and the optimal pathway (with the lowest energy barrier) for Nm' = 1 is determined. Next, more explicit H2Os are added one by one until the inner-sphere is fully hydrogen bonded. Finally, the optimal pathways with Nm' = 0-7 are obtained. The structural and energetic parameters as well as the lifetimes of the transition states are compared with the results obtained with the "Independent-minimum" method and the "Independent-average" method, and all three methods show that the pathway with Nm' = 6 may be representative. Our results give a new idea for finding the representative pathway for water-exchange reactions in other hydrated metal ion systems.
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Affiliation(s)
- Li Liu
- School of Chemistry and Chemical Engineering, State Key Laboratory of Coordination Chemistry of China & Key Laboratory of MOE for Life Science, Nanjing University, Nanjing 210023, China.
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12
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Lee Y, Thirumalai D, Hyeon C. Ultrasensitivity of Water Exchange Kinetics to the Size of Metal Ion. J Am Chem Soc 2017; 139:12334-12337. [PMID: 28853881 DOI: 10.1021/jacs.7b04198] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Metal ions play a vital role in many biological processes. An important factor in these processes is the dynamics of exchange between ion bound-water molecules and the bulk. Although structural and dynamical properties of labile waters bound to metal ions, such as Na+ and Ca2+, can be elucidated using molecular dynamics simulations, direct evaluation of rates of exchange of waters rigidly bound to high charge density Mg2+, has been elusive. Here, we report a universal relationship, allowing us to determine the water exchange time on metal ions as a function of valence and hydration radius. The proposed relationship, which covers times spanning 14 orders of magnitude, highlights the ultrasensitivity of water lifetime to the ion size, as exemplified by divalent ions, Ca2+ (∼100 ps) and Mg2+ (∼1.5 μs). We show that even when structures, characterized by radial distributions are similar, a small difference in hydration radius leads to a qualitatively different (associative or dissociative) mechanism of water exchange. Our work provides a theoretical basis for determination of hydration radius, which is critical for accurately modeling the water dynamics around multivalent ions, and hence in describing all electrostatically driven events such as ribozyme folding and catalysis.
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Affiliation(s)
- Yuno Lee
- Korea Institute for Advanced Study , Seoul 02455, Korea
| | - D Thirumalai
- Department of Chemistry, University of Texas , Austin, Texas 78712-1224, United States
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13
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Chen Y, Bylaska EJ, Weare JH. Weakly bound water structure, bond valence saturation and water dynamics at the goethite (100) surface/aqueous interface: ab initio dynamical simulations. GEOCHEMICAL TRANSACTIONS 2017; 18:3. [PMID: 29086806 PMCID: PMC5374091 DOI: 10.1186/s12932-017-0040-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 03/10/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Many important geochemical and biogeochemical reactions occur in the mineral/formation water interface of the highly abundant mineral, goethite [α-Fe(OOH)]. Ab initio molecular dynamics (AIMD) simulations of the goethite α-FeOOH (100) surface and the structure, water bond formation and dynamics of water molecules in the mineral/aqueous interface are presented. Several exchange correlation functionals were employed (PBE96, PBE96 + Grimme, and PBE0) in the simulations of a (3 × 2) goethite surface with 65 absorbed water molecules in a 3D-periodic supercell (a = 30 Å, FeOOH slab ~12 Å thick, solvation layer ~18 Å thick). RESULTS The lowest energy goethite (100) surface termination model was determined to have an exposed surface Fe3+ that was loosely capped by a water molecule and a shared hydroxide with a neighboring surface Fe3+. The water molecules capping surface Fe3+ ions were found to be loosely bound at all DFT levels with and without Grimme corrections, indicative that each surface Fe3+ was coordinated with only five neighbors. These long bonds were supported by bond valence theory calculations, which showed that the bond valence of the surface Fe3+ was saturated and surface has a neutral charge. The polarization of the water layer adjacent to the surface was found to be small and affected only the nearest water. Analysis by density difference plots and localized Boys orbitals identified three types of water molecules: those loosely bound to the surface Fe3+, those hydrogen bonded to the surface hydroxyl, and bulk water with tetrahedral coordination. Boys orbital analysis showed that the spin down lone pair orbital of the weakly absorbed water interact more strongly with the spin up Fe3+ ion. These weakly bound surface water molecules were found to rapidly exchange with the second water layer (~0.025 exchanges/ps) using a dissociative mechanism. CONCLUSIONS Water molecules adjacent to the surface were found to only weakly interact with the surface and as a result were readily able to exchange with the bulk water. To account for the large surface Fe-OH2 distances in the DFT calculations it was proposed that the surface Fe3+ atoms, which already have their bond valence fully satisfied with only five neighbors, are under-coordinated with respect to the bulk coordination. Graphical abstract All first principle calculations, at all practically achievable levels, for the goethite 100 aqueous interface support a long bond and weak interaction between the exposed surface Fe3+ and water molecules capping the surface. This result is supported by bond valence theory calculations and is indicative that each surface Fe3+ is coordinated with only 5 neighbors.
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Affiliation(s)
- Ying Chen
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093 USA
| | - Eric J. Bylaska
- William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354 USA
| | - John H. Weare
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093 USA
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15
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Fulton JL, Govind N, Huthwelker T, Bylaska EJ, Vjunov A, Pin S, Smurthwaite TD. Electronic and Chemical State of Aluminum from the Single- (K) and Double-Electron Excitation (KLII&III, KLI) X-ray Absorption Near-Edge Spectra of α-Alumina, Sodium Aluminate, Aqueous Al3+·(H2O)6, and Aqueous Al(OH)4–. J Phys Chem B 2015; 119:8380-8. [DOI: 10.1021/jp511602n] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
| | | | - Thomas Huthwelker
- Swiss Light Source,
Laboratory for Catalysis and Sustainable Chemistry (LSK), Paul Scherrer Institut (PSI), 5232 Villigen, Switzerland
| | | | | | - Sonia Pin
- Swiss Light Source,
Laboratory for Catalysis and Sustainable Chemistry (LSK), Paul Scherrer Institut (PSI), 5232 Villigen, Switzerland
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16
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Mitev PD, Bakó I, Eriksson A, Hermansson K. Large polarization but small electron transfer for water around Al(3+) in a highly hydrated crystal. Phys Chem Chem Phys 2014; 16:9351-63. [PMID: 24718484 DOI: 10.1039/c3cp55358b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Precise molecular-level information on the water molecule is precious, since it affects our interpretation of the role of water in a range of important applications of aqueous media. Here we propose that electronic structure calculations for highly hydrated crystals yield such information. Properties of nine structurally different water molecules (19 independent OO hydrogen bonds) in the Al(NO3)3·9H2O crystal have been calculated from DFT calculations. We combine the advantage of studying different water environments using one and the same compound and method (instead of comparing a set of independent experiments, each with its own set of errors) with the advantage of knowing the exact atomic positions, and the advantage of calculating properties that are difficult to extract from experiment. We find very large Wannier dipole moments for H2O molecules surrounding the cations: 4.0-4.3 D (compared to our calculated value of 1.83 D in the gas phase). These are induced by the ions and the H-bonds, while other water interactions and the relaxation of the internal water geometry in fact decrease the dipole moments. We find a good correlation between the water dipole moment and the OO distances, and an even better (non-linear) correlation with the average electric field over the molecule. Literature simulation data for ionic aqueous solutions fit quite well with our crystalline 'dipole moment vs. OO distance' curve. The progression of the water and cation charges from 'small clusters ⇒ large clusters ⇒ the crystal' helps explain why the net charges on all the water molecules are so small in the crystal.
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Affiliation(s)
- Pavlin D Mitev
- Department of Chemistry, The Ångström Laboratory, Uppsala University, Box 538, S-751 21 Uppsala, Sweden.
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17
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Zhang R, Zhuang W. Cation effect in the ionic solution optical Kerr effect measurements: A simulation study. J Chem Phys 2014; 140:054507. [PMID: 24511952 DOI: 10.1063/1.4863696] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ruiting Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, People's Republic of China
| | - Wei Zhuang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, People's Republic of China
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18
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Miliordos E, Xantheas SS. Elucidating the mechanism behind the stabilization of multi-charged metal cations in water: a case study of the electronic states of microhydrated Mg2+, Ca2+ and Al3+. Phys Chem Chem Phys 2014; 16:6886-92. [DOI: 10.1039/c3cp53636j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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19
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Odoh SO, Bylaska EJ, de Jong WA. Coordination and hydrolysis of plutonium ions in aqueous solution using Car-Parrinello molecular dynamics free energy simulations. J Phys Chem A 2013; 117:12256-67. [PMID: 24168210 DOI: 10.1021/jp4096248] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Car-Parrinello molecular dynamics (CPMD) simulations have been used to examine the hydration structures, coordination energetics, and the first hydrolysis constants of Pu(3+), Pu(4+), PuO2(+), and PuO2(2+) ions in aqueous solution at 300 K. The coordination numbers and structural properties of the first shell of these ions are in good agreement with available experimental estimates. The hexavalent PuO2(2+) species is coordinated to five aquo ligands while the pentavalent PuO2(+) complex is coordinated to four aquo ligands. The Pu(3+) and Pu(4+) ions are both coordinated to eight water molecules. The first hydrolysis constants obtained for Pu(3+) and PuO2(2+) are 6.65 and 5.70, respectively, all within 0.3 pH unit of the experimental values (6.90 and 5.50, respectively). The hydrolysis constant of Pu(4+), 0.17, disagrees with the value of -0.60 in the most recent update of the Nuclear Energy Agency Thermochemical Database (NEA-TDB) but supports recent experimental findings. The hydrolysis constant of PuO2(+), 9.51, supports the experimental results of Bennett et al. [Radiochim. Acta 1992, 56, 15]. A correlation between the pKa of the first hydrolysis reaction and the effective charge of the plutonium center was found.
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Affiliation(s)
- Samuel O Odoh
- Environmental and Molecular Science Laboratory, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
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20
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Smirnov PR, Trostin VN. Structural parameters of the close environment of group III metal ions in aqueous solutions of their salts. RUSS J GEN CHEM+ 2013. [DOI: 10.1134/s1070363213010039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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21
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Bogatko S, Cauët E, Bylaska E, Schenter G, Fulton J, Weare J. The aqueous Ca2+ system, in comparison with Zn2+, Fe3+, and Al3+: an ab initio molecular dynamics study. Chemistry 2013; 19:3047-60. [PMID: 23315704 DOI: 10.1002/chem.201202821] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Indexed: 11/08/2022]
Abstract
Herein, we report on the structure and dynamics of the aqueous Ca(2+) system studied by using ab initio molecular dynamics (AIMD) simulations. Our detailed study revealed the formation of well-formed hydration shells with characteristics that were significantly different to those of bulk water. To facilitate a robust comparison with state-of-the-art X-ray absorption fine structure (XAFS) data, we employ a 1st principles MD-XAFS procedure and directly compare simulated and experimental XAFS spectra. A comparison of the data for the aqueous Ca(2+) system with those of the recently reported Zn(2+), Fe(3+), and Al(3+) species showed that many of their structural characteristics correlated well with charge density on the cation. Some very important exceptions were found, which indicated a strong sensitivity of the solvent structure towards the cation's valence electronic structure. Average dipole moments for the 2nd shell of all cations were suppressed relative to bulk water.
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Affiliation(s)
- Stuart Bogatko
- Chemistry and Biochemistry Department, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA.
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22
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Cauët E, Bogatko SA, Bylaska EJ, Weare JH. Ion Association in AlCl3 Aqueous Solutions from Constrained First-Principles Molecular Dynamics. Inorg Chem 2012; 51:10856-69. [DOI: 10.1021/ic301346k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Emilie Cauët
- Department of Chemistry and
Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Stuart A. Bogatko
- Department of Chemistry and
Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Eric J. Bylaska
- Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington
99352, United States
| | - John H. Weare
- Department of Chemistry and
Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
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23
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Burrows HD, Costa D, Ramos ML, Miguel MDG, Teixeira MH, Pais AACC, Valente AJM, Bastos M, Bai G. Does cation dehydration drive the binding of metal ions to polyelectrolytes in water? What we can learn from the behaviour of aluminium(III) and chromium(III). Phys Chem Chem Phys 2012; 14:7950-3. [PMID: 22569828 DOI: 10.1039/c2cp40480j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Much stronger binding is seen in aqueous solutions between the anionic polyelectrolyte potassium poly(vinyl sulfate) and the substitution labile aluminium(III) than with the kinetically inert chromium(III). This strongly supports the idea that entropy driven water loss from the hydration sphere of the metal ion plays a major role in driving binding of the trivalent metal ion to the polyelectrolyte.
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Affiliation(s)
- Hugh D Burrows
- Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal.
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24
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Bogatko S, Geerlings P. Factors influencing Al3+-dimer speciation and stability from density functional theory calculations. Phys Chem Chem Phys 2012; 14:8058-66. [DOI: 10.1039/c2cp40885f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Waluyo I, Huang C, Nordlund D, Weiss TM, Pettersson LGM, Nilsson A. Increased fraction of low-density structures in aqueous solutions of fluoride. J Chem Phys 2011; 134:224507. [PMID: 21682525 DOI: 10.1063/1.3597606] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
X-ray absorption spectroscopy (XAS) and small angle x-ray scattering (SAXS) were utilized to study the effect of fluoride (F(-)) anion in aqueous solutions. XAS spectra show that F(-) increases the number of strong H-bonds, likely between F(-) and water in the first hydration shell. SAXS data show a low-Q scattering intensity increase similar to the effect of a temperature decrease, suggesting an enhanced anomalous scattering behavior in F(-) solutions. Quantitative analysis revealed that fluoride solutions have larger correlation lengths than chloride solutions with the same cations but shorter compared to pure water. This is interpreted as an increased fraction of tetrahedral low-density structures in the solutions due to the presence of the F(-) ions, which act as nucleation centers replacing water in the H-bonding network and forming stronger H-bonds, but the presence of the cations restricts the extension of strong H-bonds.
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Affiliation(s)
- Iradwikanari Waluyo
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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26
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Waluyo I, Huang C, Nordlund D, Bergmann U, Weiss TM, Pettersson LGM, Nilsson A. The structure of water in the hydration shell of cations from x-ray Raman and small angle x-ray scattering measurements. J Chem Phys 2011; 134:064513. [PMID: 21322711 PMCID: PMC3188634 DOI: 10.1063/1.3533958] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 12/15/2010] [Indexed: 01/13/2023] Open
Abstract
X-ray Raman scattering (XRS) spectroscopy and small angle x-ray scattering (SAXS) are used to study water in aqueous solutions of NaCl, MgCl(2), and AlCl(3) with the particular aim to provide information about the structure of the hydration shells of the cations. The XRS spectra show that Na(+) weakens the hydrogen bonds of water molecules in its vicinity, similar to the effect of increased temperature and pressure. Mg(2+) and Al(3+), on the other hand, cause the formation of short and strong hydrogen bonds between the surrounding water molecules. The SAXS data show that Mg(2+) and Al(3+) form tightly bound hydration shells that give a large density contrast in the scattering data. From the form factors extracted from the SAXS data, we found that Mg(2+) and Al(3+) have, respectively, an equivalent of one and one and a half stable hydration shells that appear as a density contrast. In addition, we estimated that the density of water in the hydration shells of Mg(2+) and Al(3+) is, respectively, ∼61% and ∼71% higher than in bulk water.
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Affiliation(s)
- Iradwikanari Waluyo
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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27
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Cauët E, Bogatko S, Weare JH, Fulton JL, Schenter GK, Bylaska EJ. Structure and dynamics of the hydration shells of the Zn(2+) ion from ab initio molecular dynamics and combined ab initio and classical molecular dynamics simulations. J Chem Phys 2010; 132:194502. [PMID: 20499974 DOI: 10.1063/1.3421542] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Results of ab initio molecular dynamics (AIMD) simulations (density functional theory+PBE96) of the dynamics of waters in the hydration shells surrounding the Zn(2+) ion (T approximately 300 K, rho approximately 1 gm/cm(3)) are compared to simulations using a combined quantum and classical molecular dynamics [AIMD/molecular mechanical (MM)] approach. Both classes of simulations were performed with 64 solvating water molecules ( approximately 15 ps) and used the same methods in the electronic structure calculation (plane-wave basis set, time steps, effective mass, etc.). In the AIMD/MM calculation, only six waters of hydration were included in the quantum mechanical (QM) region. The remaining 58 waters were treated with a published flexible water-water interaction potential. No reparametrization of the water-water potential was attempted. Additional AIMD/MM simulations were performed with 256 water molecules. The hydration structures predicted from the AIMD and AIMD/MM simulations are found to agree in detail with each other and with the structural results from x-ray data despite the very limited QM region in the AIMD/MM simulation. To further evaluate the agreement of these parameter-free simulations, predicted extended x-ray absorption fine structure (EXAFS) spectra were compared directly to the recently obtained EXAFS data and they agree in remarkable detail with the experimental observations. The first hydration shell contains six water molecules in a highly symmetric octahedral structure is (maximally located at 2.13-2.15 A versus 2.072 A EXAFS experiment). The widths of the peak of the simulated EXAFS spectra agree well with the data (8.4 A(2) versus 8.9 A(2) in experiment). Analysis of the H-bond structure of the hydration region shows that the second hydration shell is trigonally bound to the first shell water with a high degree of agreement between the AIMD and AIMD/MM calculations. Beyond the second shell, the bonding pattern returns to the tetrahedral structure of bulk water. The AIMD/MM results emphasize the importance of a quantum description of the first hydration shell to correctly describe the hydration region. In these calculations the full d(10) electronic structure of the valence shell of the Zn(2+) ion is retained. The simulations show substantial and complex charge relocation on both the Zn(2+) ion and the first hydration shell. The dipole moment of the waters in the first hydration shell is 3.4 D (3.3 D AIMD/MM) versus 2.73 D bulk. Little polarization is found for the waters in the second hydration shell (2.8 D). No exchanges were seen between the first and the second hydrations shells; however, many water transfers between the second hydration shell and the bulk were observed. For 64 waters, the AIMD and AIMD/MM simulations give nearly identical results for exchange dynamics. However, in the larger particle simulations (256 waters) there is a significant reduction in the second shell to bulk exchanges.
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Affiliation(s)
- Emilie Cauët
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
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28
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Terrier C, Vitorge P, Gaigeot MP, Spezia R, Vuilleumier R. Density functional theory based molecular dynamics study of hydration and electronic properties of aqueous La3+. J Chem Phys 2010; 133:044509. [DOI: 10.1063/1.3460813] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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29
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Bogatko SA, Bylaska EJ, Weare JH. First principles simulation of the bonding, vibrational, and electronic properties of the hydration shells of the high-spin Fe(3+) ion in aqueous solutions. J Phys Chem A 2010; 114:2189-200. [PMID: 20078102 DOI: 10.1021/jp904967n] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Results of parameter-free first principles simulations of a spin up 3d(5) Fe(3+) ion hydrated in an aqueous solution (64 waters, 30 ps, 300 K) are reported. The first hydration shell associated with the first maximum of the radial distribution function, g(FeO)(r), at d(Fe-O(I)) = 2.11-2.15 A, contains 6 waters with average d(OH) = 0.99 A, in good agreement with observations. A second shell with average coordination number 13.3 can be identified with average shell radius of d(Fe-O(II)) = 4.21-4.32 A. The waters in this hydration shell are coordinated to the first shell via a trigonal H-bond network with d(O(I)-O(II)) = 2.7-2.9 A, also in agreement with experimental measurements. The first shell tilt angle average is 33.4 degrees as compared to the reported value of 41 degrees . Wannier-Boys orbitals (WBO) show an interaction between the unoccupied 3d orbitals of the Fe(3+) valence (spin up, 3d(5)) and the occupied spin down lone pair orbitals of first shell waters. The effect of the spin ordering of the Fe(3+) ion on the WBO is not observed beyond the first shell. From this local bond analysis and consistent with other observations, the electronic structure of waters in the second shell is similar to that of a bulk water even in this strongly interacting system. H-bond decomposition shows significant bulk-like structure within the second shell for Fe(3+). The vibrational density of states shows a first shell red shift of 230 cm(-1) for the v(1),2v(2),v(3) overtone, in reasonable agreement with experimental estimates for trivalent cations (300 cm(-1)). No exchanges between first and second shell were observed. Waters in the second shell exchanged with bulk waters via dissociative and associative mechanisms. Results are compared with an AIMD study of Al(3+) and 64 waters. For Fe(3+) the average first shell tilt angle is larger and the tilt angle distribution wider. H-bond decomposition shows that second shell to second shell H-bonding is enhanced in Fe(3+) suggesting an earlier onset of bulk-like water structure.
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Affiliation(s)
- Stuart A Bogatko
- Chemistry and Biochemistry Department, University of California San Diego, San Diego, USA
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30
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Faro TMC, Thim GP, Skaf MS. A Lennard-Jones plus Coulomb potential for Al3+ ions in aqueous solutions. J Chem Phys 2010; 132:114509. [DOI: 10.1063/1.3364110] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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31
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Yang W, Qian Z, Miao Q, Wang Y, Bi S. Density functional theory study of the aluminium(iii) hydrolysis in aqueous solution. Phys Chem Chem Phys 2009; 11:2396-401. [DOI: 10.1039/b819484j] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Hay MB, Myneni SCB. Geometric and Electronic Structure of the Aqueous Al(H2O)63+ Complex. J Phys Chem A 2008; 112:10595-603. [DOI: 10.1021/jp802675v] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michael B. Hay
- Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey 08544, Department of Geosciences, 151 Guyot Hall, Princeton University, Princeton, New Jersey 08544, and Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Satish C. B. Myneni
- Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey 08544, Department of Geosciences, 151 Guyot Hall, Princeton University, Princeton, New Jersey 08544, and Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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33
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Hofer TS, Randolf BR, Rode BM. Al(III) hydration revisited. An ab initio quantum mechanical charge field molecular dynamics study. J Phys Chem B 2008; 112:11726-33. [PMID: 18729393 DOI: 10.1021/jp802663h] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To assess the novel quantum mechanical charge field (QMCF) molecular dynamics (MD) approach, two simulations of hydrated Al(III) have been carried out, as this system proved to be a well-suited test case for hybrid ab initio/molecular mechanics simulations. Two different population analysis schemes according to Mulliken and Lowdin have been applied to evaluate the atomic charges in the QM region. It is shown that the QMCF MD approach yields a substantially improved description of the system and that, due to the fact that solute-solvent potentials can be renounced, the QMCF MD framework is a more convenient approach to investigate solvated systems compared to conventional ab initio QM/MM MD approaches.
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Affiliation(s)
- Thomas S Hofer
- Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 52a, Innsbruck, Austria
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34
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Nichols P, Bylaska EJ, Schenter GK, de Jong W. Equatorial and apical solvent shells of the UO22+ ion. J Chem Phys 2008; 128:124507. [DOI: 10.1063/1.2884861] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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35
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Evans RJ, Rustad JR, Casey WH. Calculating Geochemical Reaction Pathways - Exploration of the Inner-Sphere Water Exchange Mechanism in Al(H2O)63+(aq) + nH2O with ab Initio Calculations and Molecular Dynamics. J Phys Chem A 2008; 112:4125-40. [DOI: 10.1021/jp7116888] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R. James Evans
- Department of Geology and Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616
| | - James R. Rustad
- Department of Geology and Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616
| | - William H. Casey
- Department of Geology and Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616
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