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Kwan V, Consta S, Malek SMA. Variation of Surface Propensity of Halides with Droplet Size and Temperature: The Planar Interface Limit. J Phys Chem B 2024; 128:193-207. [PMID: 38127582 DOI: 10.1021/acs.jpcb.3c05701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The radial number density profiles of halide and alkali ions in aqueous clusters with equimolar radius ≲1.4 nm, which correspond to ≲255 H2O molecules, have been extensively studied by computations. However, the surface abundance of Cl-, Br-, and I- relative to the bulk interior in these smaller clusters may not be representative of the larger systems. Indeed, here we show that the larger the cluster is, the lower the relative surface abundance of chaotropic halides is. In droplets with an equimolar radius of ≈2.45 nm, which corresponds to ≈2000 H2O molecules, the polarizable halides show a clear number density maximum in the droplet's bulk-like interior. A similar pattern is observed in simulations of the aqueous planar interface with halide salts at room temperature. At elevated temperature the surface propensity of Cl- decreases gradually, while that of I- is partially preserved. The change in the chaotropic halide location at higher temperatures than the room temperature may considerably affect photochemical reactivity in atmospheric aerosols, vapor-liquid nucleation and growth mechanisms, and salt crystallization via solvent evaporation. We argue that the commonly used approach of nullifying parameters in a force field in order to find the factors that determine the ion location does not provide transferable insight into other force fields.
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Affiliation(s)
- Victor Kwan
- Department of Chemistry, The University of Western Ontario, London, ON, Canada N6A 5B7
| | - Styliani Consta
- Department of Chemistry, The University of Western Ontario, London, ON, Canada N6A 5B7
| | - Shahrazad M A Malek
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, Canada A1B 3X7
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Acar M, Tatini D, Ninham BW, Rossi F, Marchettini N, Lo Nostro P. The Lyotropic Nature of Halates: An Experimental Study. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238519. [PMID: 36500616 PMCID: PMC9739596 DOI: 10.3390/molecules27238519] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/24/2022] [Accepted: 11/25/2022] [Indexed: 12/12/2022]
Abstract
Unlike halides, where the kosmotropicity decreases from fluoride to iodide, the kosmotropic nature of halates apparently increases from chlorate to iodate, in spite of the lowering in the static ionic polarizability. In this paper, we present an experimental study that confirms the results of previous simulations. The lyotropic nature of aqueous solutions of sodium halates, i.e., NaClO3, NaBrO3, and NaIO3, is investigated through density, conductivity, viscosity, and refractive index measurements as a function of temperature and salt concentration. From the experimental data, we evaluate the activity coefficients and the salt polarizability and assess the anions' nature in terms of kosmotropicity/chaotropicity. The results clearly indicate that iodate behaves as a kosmotrope, while chlorate is a chaotrope, and bromate shows an intermediate nature. This experimental study confirms that, in the case of halates XO3-, the kosmotropic-chaotropic ranking reverses with respect to halides. We also discuss and revisit the role of the anion's polarizability in the interpretation of Hofmeister phenomena.
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Affiliation(s)
- Mert Acar
- Department of Chemistry “Ugo Schiff” and CSGI, University of Florence, 50019 Firenze, Italy
| | - Duccio Tatini
- Department of Chemistry “Ugo Schiff” and CSGI, University of Florence, 50019 Firenze, Italy
| | - Barry W. Ninham
- Materials Physics (Formerly Department of Applied Mathematics), Research School of Physics, Australian National University, Canberra, ACT 2600, Australia
- School of Science, University of New South Wales, Northcott Drive, Campbell, Canberra, ACT 2612, Australia
| | - Federico Rossi
- Department of Earth, Environmental and Physical Sciences, University of Siena, 53100 Siena, Italy
| | - Nadia Marchettini
- Department of Earth, Environmental and Physical Sciences, University of Siena, 53100 Siena, Italy
| | - Pierandrea Lo Nostro
- Department of Chemistry “Ugo Schiff” and CSGI, University of Florence, 50019 Firenze, Italy
- Correspondence: ; Tel.: +39-055-4573010
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Roy S, Mondal JA. "Breaking" and "Making" of Water Structure at the Air/Water-Electrolyte (NaXO 3; X = Cl, Br, I) Interface. J Phys Chem Lett 2021; 12:1955-1960. [PMID: 33591757 DOI: 10.1021/acs.jpclett.0c03827] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The prevalence of ions at the aqueous interface has been widely recognized, but their effect on the structure of interfacial water (e.g., hydrogen (H)-bonding) remains enigmatic. Using heterodyne-detected vibrational sum frequency generation (HD-VSFG) and Raman difference spectroscopy with simultaneous curve fitting (DS-SCF) analysis, we show that the ion-induced perturbations of H-bonding at the air/water interface and in the bulk water are strongly correlated. Specifically, the structure-breaking anions such as ClO3- decrease the average H-bonding of water at the air/water interface, as it does to the water in its hydration shell in the bulk. The structure-making anion of the same series (IO3-) does exactly the reverse. None of the electrolytes (NaXO3; X = Cl, Br, I) form well-defined electric double layers that significantly increase or reverse the hydrogen-down (H-down) orientation of water at the air/water interface. These results provide a unified picture of specific anion effect at the air/water interface and in the bulk water.
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Affiliation(s)
- Subhadip Roy
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Homi Bhabha National Institute, Trombay, Mumbai 400085, India
| | - Jahur Alam Mondal
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Homi Bhabha National Institute, Trombay, Mumbai 400085, India
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Yadav S, Chandra A. Transport of hydrated nitrate and nitrite ions through graphene nanopores in aqueous medium. J Comput Chem 2020; 41:1850-1858. [PMID: 32500955 DOI: 10.1002/jcc.26356] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 05/13/2020] [Accepted: 05/17/2020] [Indexed: 11/11/2022]
Abstract
Nitrate ( NO 3 - ) and nitrite ( NO 2 - ) ions are naturally occurring inorganic ions that are part of the nitrogen cycle. High doses of these ions in drinking water impose a potential risk to public health. In this work, molecular dynamics simulations are carried out to study the passage of nitrate and nitrite ions from water through graphene nanosheets (GNS) with hydrogen-functionalized narrow pores in presence of an external electric field. The passage of ions through the pores is investigated through calculations of ion flux, and the results are analyzed through calculations of various structural and thermodynamic properties such as the density of ions and water, ion-water radial distribution functions, two-dimensional density distribution functions, and the potentials of mean force of the ions. Current simulations show that the nitrite ions can pass more in numbers than the nitrate ions in a given time through GNS hydrogen-functionalized pore of different geometry. It is found that the nitrite ions can permeate faster than the nitrate ions despite the former having higher hydration energy in the bulk. This can be explained in terms of the competition between the number density of the ions along the pore axis and the free energy barrier calculated from the potential of mean force. Also, an externally applied electric field is found to be important for faster permeation of the nitrite over the nitrate ions. The current study suggests that graphene nanosheets with carefully created pores can be effective in achieving selective passage of ions from aqueous solutions.
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Affiliation(s)
- Sushma Yadav
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh, India.,International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Ibaraki, Japan
| | - Amalendu Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh, India
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5
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Nuclear Magnetic Resonance with Fast Field-Cycling Setup: A Valid Tool for Soil Quality Investigation. AGRONOMY-BASEL 2020. [DOI: 10.3390/agronomy10071040] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Nuclear magnetic resonance (NMR) techniques are largely employed in several fields. As an example, NMR spectroscopy is used to provide structural and conformational information on pure systems, while affording quantitative evaluation on the number of nuclei in a given chemical environment. When dealing with relaxation, NMR allows understanding of molecular dynamics, i.e., the time evolution of molecular motions. The analysis of relaxation times conducted on complex liquid–liquid and solid–liquid mixtures is directly related to the nature of the interactions among the components of the mixture. In the present review paper, the peculiarities of low resolution fast field-cycling (FFC) NMR relaxometry in soil science are reported. In particular, the general aspects of the typical FFC NMR relaxometry experiment are firstly provided. Afterwards, a discussion on the main mathematical models to be used to “read” and interpret experimental data on soils is given. Following this, an overview on the main results in soil science is supplied. Finally, new FFC NMR-based hypotheses on nutrient dynamics in soils are described
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Solé-Daura A, Poblet JM, Carbó JJ. Structure-Activity Relationships for the Affinity of Chaotropic Polyoxometalate Anions towards Proteins. Chemistry 2020; 26:5799-5809. [PMID: 32104951 DOI: 10.1002/chem.201905533] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Indexed: 12/31/2022]
Abstract
The influence of the composition of chaotropic polyoxometalate (POM) anions on their affinity to biological systems was studied by means of atomistic molecular dynamics (MD) simulations. The variations in the affinity to hen egg-white lysozyme (HEWL) were analyzed along two series of POMs whereby the charge or the size and shape of the metal cluster are modified systematically. Our simulations revealed a quadratic relationship between the charge of the POM and its affinity to HEWL as a consequence of the parabolic growth of POM⋅⋅⋅water interaction with the charge. As the charge increases, POMs become less chaotropic (more kosmotropic) increasing the number and the strength of POM-water hydrogen bonds and structuring the solvation shell around the POM. This atomistic description explains the proportionally larger desolvation energies and less protein affinity for highly charged POMs, and consequently, the preference for moderate charge densities (q/M=0.33). Also, our simulations suggest that POM⋅⋅⋅protein interactions are size-specific. The cationic pockets of HEWL protein show a preference for Keggin-like structures, which display the optimal dimensions (≈1 nm). Finally, we developed a quantitative multidimensional model for protein affinity with predictive ability (r2 =0.97; q2 =0.88) using two molecular descriptors that account for the charge density (charge per metal atom ratio; q/M) and the size and shape (shape weighted-volume; VS ).
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Affiliation(s)
- Albert Solé-Daura
- Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel⋅lí Domingo 1, 43007, Tarragona, Spain
| | - Josep M Poblet
- Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel⋅lí Domingo 1, 43007, Tarragona, Spain
| | - Jorge J Carbó
- Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel⋅lí Domingo 1, 43007, Tarragona, Spain
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Hull KL, Schipper DE, Oliver AG. Synthesis and structural characterization of CO 2-soluble oxidizers [Bu 4N]BrO 3 and [Bu 4N]ClO 3 and their dissolution in cosolvent-modified CO 2 for reservoir applications. RSC Adv 2020; 10:44973-44980. [PMID: 35516229 PMCID: PMC9058644 DOI: 10.1039/d0ra09563j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/25/2021] [Accepted: 12/01/2020] [Indexed: 12/15/2022] Open
Abstract
CO2 utilization in upsteam oil and gas applications requires CO2-soluble additives such as polymers, surfactants, and other components. Here we report the facile synthesis of CO2-soluble oxidizers composed of judiciously selected organic cations paired with oxidizing anions. [Bu4N]BrO3 and [Bu4N]ClO3 are prepared using a double displacement synthetic strategy, whereby the crystalline product is readily obtained in high yield and structurally characterized using single-crystal X-ray diffraction. The facility of the approach is demonstrated through the preparation of several additional alkylammonium bromate compounds. Static solubility studies using a high-pressure cell with viewing windows showed that tetrabutylammonium compounds could be solubilized using cosolvent-modified CO2. Using 4 mol% ethanol as cosolvent, >3 mM [Bu4N]BrO3 could be dissolved in CO2, while ∼0.75 mM [Bu4N]ClO3 could be dissolved in the same solvent system. The solubility properties of [Bu4N]BrO3 along with its thermal stability up to ∼200 °C suggest that it is a promising oilfield oxidizer that can be utilized in subterranean CO2 applications. Bromate and chlorate salts were hydrophobically modified with tetrabutylammonium to yield oxidizers that are soluble in CO2-cosolvent mixtures.![]()
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Affiliation(s)
| | | | - Allen G. Oliver
- The Department of Chemistry and Biochemistry
- University of Notre Dame
- USA
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Nair AS, Banerjee P, Sarkar S, Bagchi B. Dynamics of linear molecules in water: Translation-rotation coupling in jump motion driven diffusion. J Chem Phys 2019; 151:034301. [PMID: 31325934 DOI: 10.1063/1.5100930] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We study by computer simulations, and by theory, the coupled rotational and translational dynamics of three important linear diatomic molecules, namely, carbon monoxide (CO), nitric oxide (NO), and cyanide ion (CN-) in water. Translational diffusion of these molecules is found to be strongly coupled to their own rotational dynamics which, in turn, are coupled to similar motions of the surrounding water. In particular, we find that coupled orientational jump motions play an important role in all three cases. While CO and NO show similar features, CN- exhibits certain differences. Our results agree well with the known experimental values of the diffusion coefficient. We examined the validity of hydrodynamic predictions and found them to be inadequate, particularly for rotational diffusion. A mode coupling theory approach is developed and applied to understand the complexity of translation-rotation coupling.
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Affiliation(s)
- Anjali S Nair
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Puja Banerjee
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Sarmistha Sarkar
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Biman Bagchi
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
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Affiliation(s)
- Puja Banerjee
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, India
| | - Biman Bagchi
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, India
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