1
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Chio CC, Tse YLS. Reparameterization of Polarizable Force Fields for Studying Ion Transfer across Liquid-Liquid Interfaces. J Phys Chem B 2024; 128:1987-1999. [PMID: 38356148 DOI: 10.1021/acs.jpcb.3c07055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
We have developed a general scheme for refining classical polarizable molecular dynamics (MD) force fields that can accurately describe the molecular interactions in systems with liquid-liquid interfaces. While ab initio MD (AIMD) simulations can naturally describe molecular interactions, they are often so computationally expensive that simulating large system sizes and/or long time scales is usually infeasible. To resolve this, we parameterized efficient and accurate classical polarizable force fields that use AIMD reference data by minimizing both the relative entropy and the root mean squared deviation in atomic forces. We utilized our new multiscale models to study chloride ion transfer across the water-dichloromethane (DCM) interface with and without the tetraethylammonium cation as the phase-transfer catalyst. Our calculated free-energy barrier for the water-DCM interface is consistent with the other reported simulation results. We further analyzed the ion-transfer process by studying the hydration shell structures around the chloride ion and the ion-pair formation to better understand the mechanism. We observed that electronic polarizability is an important factor for the studied phase-transfer catalyst to lower the free-energy barrier of the ion transfer. Using the water-benzene interface system as an additional example, we show that our parameterization scheme provides a general route for modeling different liquid-liquid interface systems even when the experimental data or force field parameters are not readily available.
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Affiliation(s)
- Chung Chi Chio
- Department of Chemistry, The Chinese University of Hong Kong, Sha Tin, New Territories, Hong Kong, China
| | - Ying-Lung Steve Tse
- Department of Chemistry, The Chinese University of Hong Kong, Sha Tin, New Territories, Hong Kong, China
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2
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Nakao K, Noda K, Hashimoto H, Nakagawa M, Nishimi T, Ohira A, Sato Y, Kato D, Kamata T, Niwa O, Kunitake M. Electrochemistry in bicontinuous microemulsions derived from two immiscible electrolyte solutions for a membrane-free redox flow battery. J Colloid Interface Sci 2023; 641:348-358. [PMID: 36940591 DOI: 10.1016/j.jcis.2023.03.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 03/04/2023] [Accepted: 03/09/2023] [Indexed: 03/16/2023]
Abstract
HYPOTHESES Bicontinuous microemulsions (BMEs) have attracted attention as unique heterogeneous mixture for electrochemistry. An interface between two immiscible electrolyte solutions (ITIES) is an electrochemical system that straddles the interface between a saline and an organic solvent with a lipophilic electrolyte. Although most BMEs have been reported with nonpolar oils, such as toluene and fatty acids, it should be possible to construct a sponge-like three-dimensionally expanded ITIES comprising a BME phase. EXPERIMENTS Dichloromethane (DCM)-water microemulsions stabilized by a surfactant were investigated in terms of the concentrations of co-surfactants and hydrophilic/lipophilic salts. A Winsor III microemulsion three-layer system, consisting of an upper saline phase, a middle BME phase, and a lower DCM phase, was prepared, and electrochemistry was conducted in each phase. FINDINGS We found the conditions for ITIES-BME phases. Regardless of where the three electrodes were placed in the macroscopically heterogeneous three-layer system, electrochemistry was possible, as in a homogeneous electrolyte solution. This indicates that the anodic and cathodic reactions can be divided into two immiscible solution phases. A redox flow battery comprising a three-layer system with a BME as the middle phase was demonstrated, paving the way for applications such as electrolysis synthesis and secondary batteries.
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Affiliation(s)
- Kodai Nakao
- Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan; Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Koji Noda
- Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan
| | - Hinako Hashimoto
- Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan
| | - Mayuki Nakagawa
- Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan
| | - Taisei Nishimi
- Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem), Room 422, Bldg. 12, Faculty of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Akihiro Ohira
- Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Yukari Sato
- Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Dai Kato
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Tomoyuki Kamata
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Osamu Niwa
- Advanced Science Research Laboratory, Saitama Institute of Technology, 1690 Fusaiji, Fukaya, Saitama 369-0293, Japan
| | - Masashi Kunitake
- Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan; Institute of Industrial Nanomaterials, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
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3
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Benjamin I. Structure, Thermodynamics, and Dynamics of Thiocyanate Ion Adsorption and Transfer across the Water/Toluene Interface. J Phys Chem B 2022; 126:5706-5714. [PMID: 35861680 DOI: 10.1021/acs.jpcb.2c03956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular dynamics simulations are used to examine in detail the structure, thermodynamics, and dynamics involve in the adsorption and transfer of the thiocyanate ion (SCN-) across the water/toluene interface. Free energy, hydration structure, and several dynamical properties as a function of the ion location along the interface normal are calculated and contrasted with recent experiments. The free energy profile exhibits a local minimum near the interface corresponding to adsorption free energy relative to bulk water of -6 kJ/mol, in reasonable agreement with experiments. The simulations provide insight into the water surface fluctuations that are coupled to the ion transfer, demonstrating formation of water finger-like structures assisting the transfer process.
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Affiliation(s)
- Ilan Benjamin
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
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4
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Ahmed MMN, Bodowara FS, Zhou W, Penteado JF, Smeltz JL, Pathirathna P. Electrochemical detection of Cd(ii) ions in complex matrices with nanopipets. RSC Adv 2021; 12:1077-1083. [PMID: 35425143 PMCID: PMC8978973 DOI: 10.1039/d1ra07655h] [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: 10/16/2021] [Accepted: 12/20/2021] [Indexed: 01/24/2023] Open
Abstract
Heavy metal contamination and its detrimental health effects are a growing concern globally. Several metal mitigation systems and regulatory approaches have been implemented to minimize the negative impacts on human health. However, none of these function at maximum efficiency, mainly due to the lack of accurate information about metal speciation. Therefore, there is a critical need to develop novel, cheap, efficient, and robust metal detecting sensors. In this study, we describe the application of a nanopipet based electrochemical sensor to detect aqueous Cd(ii) ions. The inner radius of our nanopipets is ∼300 nm, and the fundamental mechanism behind our sensor's response is ion transfer between two immiscible electrolyte solutions (ITIES). The absence of redox behavior makes ITIES an excellent, attractive electrochemical tool to study various ions in aqueous solutions. In this study, we used 1,10-phenanthroline as our ionophore in the organic phase (dichloroethane) to facilitate the transfer of Cd(ii) ions from the polar aqueous phase to the less polar organic phase. Unlike previous studies, we characterized our nanopipet in complicated matrices, including, but not limited to, tris buffer and artificial seawater. We performed quantitative assessments to determine our sensor's limit of detection, stability, sensitivity, and selectivity. We further show that our nanosensor can detect free Cd(ii) ions in the presence of strong complexing agents such as ethylenediaminetetraacetic acid, 2,3-dimercaptosuccinic acid, etc. We quantified the concentration of free Cd(ii) ions in a water sample collected from a local lagoon. Thus, we showcased the power of our nanopipets to act as a robust, accurate, and efficient speciation sensor to detect Cd(ii) ions in environmental samples.
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Affiliation(s)
- Muzammil M N Ahmed
- Department of Biomedical & Chemical Engineering & Sciences, Florida Institute of Technology 150 W. University Blvd Melbourne FL 32901 USA
| | - Faieza S Bodowara
- Department of Biomedical & Chemical Engineering & Sciences, Florida Institute of Technology 150 W. University Blvd Melbourne FL 32901 USA
| | - Wendy Zhou
- Department of Biomedical & Chemical Engineering & Sciences, Florida Institute of Technology 150 W. University Blvd Melbourne FL 32901 USA
| | - Juliana F Penteado
- Department of Biomedical & Chemical Engineering & Sciences, Florida Institute of Technology 150 W. University Blvd Melbourne FL 32901 USA
| | - Jessica L Smeltz
- Department of Biomedical & Chemical Engineering & Sciences, Florida Institute of Technology 150 W. University Blvd Melbourne FL 32901 USA
| | - Pavithra Pathirathna
- Department of Biomedical & Chemical Engineering & Sciences, Florida Institute of Technology 150 W. University Blvd Melbourne FL 32901 USA
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5
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Morita A, Koizumi A, Hirano T. Recent progress in simulating microscopic ion transport mechanisms at liquid-liquid interfaces. J Chem Phys 2021; 154:080901. [PMID: 33639756 DOI: 10.1063/5.0039172] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Transport of ions through liquid-liquid interfaces is of fundamental importance to a wide variety of applications. However, since it is quite challenging for experimentalists to directly and selectively observe molecules at the interfaces, microscopic mechanisms of ion transport have been largely presumed from kinetic information. This Perspective illustrates recent examples that molecular dynamics simulations with proper free energy surfaces clarified mechanistic pictures of ion transport. The key is a proper choice of coordinates and defining/calculating free energy surfaces in multidimensional space. Once the free energy surfaces for realistic systems are available, they naturally provide new insight into the ion transport in unprecedented details, including water finger, transient ion pairing, and electron transfer.
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Affiliation(s)
- Akihiro Morita
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Ai Koizumi
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Tomonori Hirano
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
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6
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Suárez-Herrera MF, Scanlon MD. Quantitative Analysis of Redox-Inactive Ions by AC Voltammetry at a Polarized Interface between Two Immiscible Electrolyte Solutions. Anal Chem 2020; 92:10521-10530. [PMID: 32608226 DOI: 10.1021/acs.analchem.0c01340] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The interface between two immiscible electrolyte solutions (ITIES) is ideally suited to detect redox-inactive ions by their ion transfer. Such electroanalysis, based on the Nernst-Donnan equation, has been predominantly performed using amperometry, cyclic voltammetry, or differential pulse voltammetry. Here, we introduce a new electroanalytical method based on alternating-current (AC) voltammetry with inherent advantages over traditional approaches such as avoidance of positive feedback iR compensation, a major issue for liquid|liquid electrochemical cells containing resistive organic media and interfacial areas in the cm2 and mm2 range. A theoretical background outlining the generation of the analytical signal is provided and based on extracting the component that depends on the Warburg impedance from the total impedance. The quantitative detection of a series of model redox-inactive tetraalkylammonium cations is demonstrated, with evidence provided of the transient adsorption of these cations at the interface during the course of ion transfer. Since ion transfer is diffusion-limited, by changing the voltage excitation frequency during AC voltammetry, the intensity of the Faradaic response can be enhanced at low frequencies (1 Hz) or made to disappear completely at higher frequencies (99 Hz). The latter produces an AC voltammogram equivalent to a "blank" measurement in the absence of analyte and is ideal for background subtraction. Therefore, major opportunities exist for the sensitive detection of ionic analyte when a "blank" measurement in the absence of analyte is impossible. This approach is particularly useful to deconvolute signals related to reversible electrochemical reactions from those due to irreversible processes, which do not give AC signals.
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Affiliation(s)
- Marco F Suárez-Herrera
- Departamento De Química, Facultad De Ciencias, Universidad Nacional De Colombia, Cra 30 # 45-03, Edificio 451, Bogotá, Colombia
| | - Micheál D Scanlon
- The Bernal Institute and Department of Chemical Sciences, School of Natural Sciences, University of Limerick (UL), Limerick V94 T9PX, Ireland
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7
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Kasuno M, Wakabayashi K, Matsuyama Y, Yamamura R. Ion transfer voltammetry at the interface of water and low dielectric constant organic solutions. Electrochim Acta 2020. [DOI: 10.1016/j.electacta.2020.136069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Wen B, Sun C, Zheng W, Bai B, Lichtfouse E. Evidence for water ridges at oil-water interfaces: implications for ion transport. SOFT MATTER 2020; 16:826-832. [PMID: 31840723 DOI: 10.1039/c9sm01791g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Understanding ion transport across interfaces is of fundamental importance in many processes such as liquid-liquid extraction, phase transfer catalysis, enhanced oil recovery and emulsion stabilisation. However, the factors that control ion transport across interfaces are poorly known due to a lack of knowledge of structural changes at interfaces. We studied here the effects of ionic concentration and external force on the transport of ions across the decane-water interface using classical molecular dynamics simulations. The results show that the evolution of interfacial structures during ion transfer across the interface is controlled by hydrogen bonding and ionic interactions at the interface. We also identified a new mode of ion transfer across the interface at low ionic concentrations, involving a 'water ridge', rather that the classical 'water finger'. In the water ridge mode, hydrogen bonds are not broken due to low ion levels, and the water ridge induces gradual interface deformation. Whereas, at high ionic concentrations, hydrogen bonds are broken by the strong ion electrostatic repulsion, thus inducing the formation of a water finger. We also found that the variation of the Gibbs free energy during ion transfer is directly relevant to the ionic concentration. The water ridge at low ionic concentrations, which displaces more water molecules towards the decane phase, induces less free energy variation than the water finger at high ionic concentrations.
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Affiliation(s)
- Boyao Wen
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
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9
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Molina Á, Laborda E, Olmos JM, Millán-Barrios E. Double Transfer Voltammetry in Two-Polarizable Interface Systems: Effects of the Lipophilicity and Charge of the Target and Compensating Ions. Anal Chem 2018; 90:3402-3408. [PMID: 29397699 DOI: 10.1021/acs.analchem.7b05051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Analytical expressions are obtained for the study of the net current and individual fluxes across macro- and micro-liquid/liquid interfaces in series as those found in ion sensing with solvent polymeric membranes and in ion-transfer batteries. The mathematical solutions deduced are applicable to any voltammetric technique, independently of the lipophilicity and charge number of the target and compensating ions. When supporting electrolytes of semihydrophilic ions are employed, the so-called double transfer voltammograms have a tendency to merge into a single signal, which complicates notably the modeling and analysis of the electrochemical response. The present theoretical results point out that the appearance of one or two voltammetric waves is highly dependent on the size of the interfaces and on the viscosity of the organic solution. Hence, the two latter can be adjusted experimentally in order to "split" the voltammograms and extract information about the ions involved. This has been illustrated in this work with the experimental study in water | 1,2-dichloroethane | water cells of the transfer of the monovalent tetraethylammonium cation compensated by anions of different lipophilicity, and also of the divalent hexachloroplatinate anion.
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Affiliation(s)
- Ángela Molina
- Departamento de Química Física, Facultad de Química, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , 30100 Murcia , Spain
| | - Eduardo Laborda
- Departamento de Química Física, Facultad de Química, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , 30100 Murcia , Spain
| | - José Manuel Olmos
- Departamento de Química Física, Facultad de Química, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , 30100 Murcia , Spain
| | - Enrique Millán-Barrios
- Laboratorio de Electroquímica, Departamento de Química, Facultad de Ciencias , Universidad de los Andes , 5101 Mérida , Venezuela
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10
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11
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Matsubara Y, Grills DC, Koide Y. Experimental Insight into the Thermodynamics of the Dissolution of Electrolytes in Room-Temperature Ionic Liquids: From the Mass Action Law to the Absolute Standard Chemical Potential of a Proton. ACS OMEGA 2016; 1:1393-1411. [PMID: 31457204 PMCID: PMC6640753 DOI: 10.1021/acsomega.6b00129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 12/12/2016] [Indexed: 06/10/2023]
Abstract
Room-temperature ionic liquids (ILs) are a class of nonaqueous solvents that have expanded the realm of modern chemistry, drawing increasing interest over the last few decades, not only in terms of their own unique physical chemistry but also in many applications including organic synthesis, electrochemistry, and biological systems, wherein charged solutes (i.e., electrolytes) often play vital roles. However, our fundamental understanding of the dissolution of an electrolyte in an IL is still rather limited. For example, the activity of a charged species has frequently been assumed to be unity without a clear experimental basis. In this study, we have discussed a standard component-based scheme for the dissolution of an electrolyte in an IL, supported by our observation of ideal Nernstian responses for the reduction of silver and ferrocenium salts in a representative IL, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([emim+][NTf2 -] or [emim+][TFSI-]). Using this scheme, which was also supported by temperature-dependent measurements with ILs having longer alkyl chains in the imidazolium ring, and the solubility of the IL in water, we established the concept of Gibbs transfer energies of "pseudo-single ions" from the IL to conventional neutral molecular solvents (water, acetonitrile, and methanol). This concept, which bridges component- and constituent-based energetics, utilizes an extrathermodynamic assumption, which itself was justified by experimental observations. These energies enable us to eliminate inner potential differences between the IL and molecular solvents (solvent-solvent interactions), that is, on a practical level, conditional liquid junction potential differences, so that we can discuss ion-solvent interactions independently. Specifically, we have examined the standard electrode potential of the ferrocenium/ferrocene redox couple, Fc+/Fc, and the absolute intrinsic standard chemical potential of a proton in [emim+][NTf2 -], finding that the proton is more acidic in the IL than in water by 6.5 ± 0.6 units on the unified pH scale. These results strengthen the progress on the physical chemistry of ions in IL solvent systems on the basis of their activities, providing a rigorous thermodynamic framework.
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Affiliation(s)
- Yasuo Matsubara
- Department
of Material and Life Chemistry, Kanagawa
University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan
| | - David C. Grills
- Chemistry
Division, Brookhaven National Laboratory, P.O. Box 5000, Upton, New
York 11973-5000, United
States
| | - Yoshihiro Koide
- Department
of Material and Life Chemistry, Kanagawa
University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan
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12
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Karnes JJ, Benjamin I. Geometric and energetic considerations of surface fluctuations during ion transfer across the water-immiscible organic liquid interface. J Chem Phys 2016; 145:014701. [DOI: 10.1063/1.4954331] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- John J. Karnes
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA
| | - Ilan Benjamin
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA
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13
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Molina Á, Olmos JM, Laborda E, Gómez-Gil JM, González J. Voltammetry of the aqueous complexation-dissociation coupled to transfer (ACDT) mechanism with charged ligands. Phys Chem Chem Phys 2016; 18:17091-104. [PMID: 27296066 DOI: 10.1039/c6cp03032g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The study of the so-called aqueous complexation-dissociation coupled to transfer (ACDT) mechanism is extended to systems where the ligand species is not neutral and so the charge of the two transferable ions is different (z1 ≠ z2). This has a profound effect on the voltammetric response of the system, which shows a complex behaviour depending on the chemical kinetics, the difference between the lipophilicity of the two ions and the applied potential. Such response is modelled making use of the diffusive-kinetic steady state (dkss) approach, obtaining analytical expressions for the current-potential-time curves in normal pulse, derivative and differential multipulse voltammetries. In addition, manageable expressions for the concentration profiles, interfacial fluxes and interfacial concentrations of all the species either side of the liquid|liquid interface are derived. From them, the effect on the voltammograms of the characteristics of the chemical reaction and the lipophilicity of the ions is thoroughly studied, comparing the cases where the ions carry the same and a different charge. The last case shows some striking behaviours that can be understood from the analysis of the concentration profiles.
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Affiliation(s)
- Ángela Molina
- Departamento de Química Física, Universidad de Murcia, Facultad de Química, Campus de Espinardo, Murcia, Spain.
| | - José Manuel Olmos
- Departamento de Química Física, Universidad de Murcia, Facultad de Química, Campus de Espinardo, Murcia, Spain.
| | - Eduardo Laborda
- Departamento de Química Física, Universidad de Murcia, Facultad de Química, Campus de Espinardo, Murcia, Spain.
| | - José María Gómez-Gil
- Departamento de Química Física, Universidad de Murcia, Facultad de Química, Campus de Espinardo, Murcia, Spain.
| | - Joaquín González
- Departamento de Química Física, Universidad de Murcia, Facultad de Química, Campus de Espinardo, Murcia, Spain.
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14
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Extraction of Sodium Picrate by 3 m-Crown- mEthers and Their Monobenzo Derivatives ( m= 5, 6) into Benzene: Estimation of Their Equilibrium-Potential Differences at the Less-Polar Diluent/Water Interface by an Extraction Method. J CHEM-NY 2016. [DOI: 10.1155/2016/5175746] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Individual distribution constants (KD,A) of picrate ion (Pic−) and extraction constants (Kex±) of NaPic by some crown ethers (L) into benzene (Bz) at 25°C were calculated from data reported previously. These constants were defined asKD,Pic=Pic-o/[Pic-]andKex±=NaL+oPic-o/(Na+Lo[Pic-]), respectively. Here, the subscript “o” denotes an organic (o) phase and practically o = Bz. 15-Crown-5 ether (15C5), 18-crown-6 one (18C6), and their monobenzo (B) derivatives (B15C5 and B18C6) were selected as L. Interfacial equilibrium-potential differences (Δϕeq) at extraction were estimated at 298 K. A plot oflogKex±versus-Δϕeqfor the four L extraction systems gave a straight line with slope = 84 V−1. This slope was compared with those, reported before, of the dichloromethane (DCM), 1,2-dichloroethane (DCE), and nitrobenzene (NB) extraction systems. The slopes of the regression lines were in the order NB < DCM ≤ DCE < Bz. Also, the individual distribution constants of the complex ionNaL+and an ion-pair complex (NaL+Pic-) into Bz phase were calculated from the above extraction data. At least, a comparison between these values suggests that Bz molecules mainly interact withNaL+moiety ofNaL+Pic-.
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15
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Arrigan DWM, Alvarez de Eulate E, Liu Y. Electroanalytical Opportunities Derived from Ion Transfer at Interfaces between Immiscible Electrolyte Solutions. Aust J Chem 2016. [DOI: 10.1071/ch15796] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This review presents an introduction to electrochemistry at interfaces between immiscible electrolyte solutions and surveys recent studies of this form of electrochemistry in electroanalytical strategies. Simple ion and facilitated ion transfers across interfaces varying from millimetre scale to nanometre scales are considered. Target detection strategies for a range of ions, inorganic, organic, and biological, including macromolecules, are discussed.
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16
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Qiao B, Anderson JR, Pink M, Flood AH. Size-matched recognition of large anions by cyanostar macrocycles is saved when solvent-bias is avoided. Chem Commun (Camb) 2016; 52:8683-6. [DOI: 10.1039/c6cc03463b] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A bulky cyanostar that only forms 1 : 1 complexes was created to study the poorly understood size dependent recognition of large anions by shape-persistent macrocycles.
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Affiliation(s)
- Bo Qiao
- Department of Chemistry
- Indiana University
- Bloomington
- USA
| | | | - Maren Pink
- Department of Chemistry
- Indiana University
- Bloomington
- USA
| | - Amar H. Flood
- Department of Chemistry
- Indiana University
- Bloomington
- USA
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17
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Abstract
The liquid interface is a narrow, highly anisotropic region, characterized by rapidly varying density, polarity, and molecular structure. I review several aspects of interfacial solvation and show how these affect reactivity at liquid/liquid interfaces. I specifically consider ion transfer, electron transfer, and SN2 reactions, showing that solvent effects on these reactions can be understood by examining the unique structure and dynamics of the liquid interface region.
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Affiliation(s)
- Ilan Benjamin
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064;
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