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Engelbrecht LDV, Ji X, Carbonaro CM, Laaksonen A, Mocci F. MD simulations explain the excess molar enthalpies in pseudo-binary mixtures of a choline chloride-based deep eutectic solvent with water or methanol. Front Chem 2022; 10:983281. [DOI: 10.3389/fchem.2022.983281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/28/2022] [Indexed: 11/16/2022] Open
Abstract
The addition of molecular liquid cosolvents to choline chloride (ChCl)-based deep eutectic solvents (DESs) is increasingly investigated for reducing the inherently high bulk viscosities of the latter, which represent a major obstacle for potential industrial applications. The molar enthalpy of mixing, often referred to as excess molar enthalpy HE—a property reflecting changes in intermolecular interactions upon mixing—of the well-known ChCl/ethylene glycol (1:2 molar ratio) DES mixed with either water or methanol was recently found to be of opposite sign at 308.15 K: Mixing of the DES with water is strongly exothermic, while methanol mixtures are endothermic over the entire mixture composition range. Knowledge of molecular-level liquid structural changes in the DES following cosolvent addition is expected to be important when selecting such “pseudo-binary” mixtures for specific applications, e.g., solvents. With the aim of understanding the reason for the different behavior of selected DES/water or methanol mixtures, we performed classical MD computer simulations to study the changes in intermolecular interactions thought to be responsible for the observed HE sign difference. Excess molar enthalpies computed from our simulations reproduce, for the first time, the experimental sign difference and composition dependence of the property. We performed a structural analysis of simulation configurations, revealing an intriguing difference in the interaction modes of the two cosolvents with the DES chloride anion: water molecules insert between neighboring chloride anions, forming ionic hydrogen-bonded bridges that draw the anions closer, whereas dilution of the DES with methanol results in increased interionic separation. Moreover, the simulated DES/water mixtures were found to contain extended hydrogen-bonded structures containing water-bridged chloride pair arrangements, the presence of which may have important implications for solvent applications.
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Han J, Mariani A, Zarrabeitia M, Jusys Z, Behm RJ, Varzi A, Passerini S. Zinc-Ion Hybrid Supercapacitors Employing Acetate-Based Water-in-Salt Electrolytes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2201563. [PMID: 35810459 DOI: 10.1002/smll.202201563] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/23/2022] [Indexed: 06/15/2023]
Abstract
Halide-free, water-in-salt electrolytes (WiSEs) composed of potassium acetate (KAc) and zinc acetate (ZnAc2 ) are investigated as electrolytes in zinc-ion hybrid supercapacitors (ZHSs). Molecular dynamics simulations demonstrate that water molecules are mostly non-interacting with each other in the highly concentrated WiSEs, while "bulk-like water" regions are present in the dilute electrolyte. Among the various concentrated electrolytes investigated, the 30 m KAc and 1 m ZnAc2 electrolyte (30K1Zn) grants the best performance in terms of reversibility and stability of Zn plating/stripping while the less concentrated electrolyte cannot suppress corrosion of Zn and hydrogen evolution. The ZHSs utilizing 30K1Zn, in combination with a commercial activated carbon (AC) positive electrode and Zn as the negative electrode, deliver a capacity of 65 mAh g-1 (based on the AC weight) at a current density of 5 A g-1 . They also offer an excellent capacity retention over 10 000 cycles and an impressive coulombic efficiency (≈100%).
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Affiliation(s)
- Jin Han
- Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, D-89081, Ulm, Germany
- Karlsruhe Institute of Technology (KIT), P.O. Box 3640, D-76021, Karlsruhe, Germany
| | - Alessandro Mariani
- Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, D-89081, Ulm, Germany
- Karlsruhe Institute of Technology (KIT), P.O. Box 3640, D-76021, Karlsruhe, Germany
| | - Maider Zarrabeitia
- Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, D-89081, Ulm, Germany
- Karlsruhe Institute of Technology (KIT), P.O. Box 3640, D-76021, Karlsruhe, Germany
| | - Zenonas Jusys
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, D-89081, Ulm, Germany
- Institute of Theoretical Chemistry, Ulm University, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
| | - R Jürgen Behm
- Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, D-89081, Ulm, Germany
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, D-89081, Ulm, Germany
- Institute of Theoretical Chemistry, Ulm University, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
| | - Alberto Varzi
- Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, D-89081, Ulm, Germany
- Karlsruhe Institute of Technology (KIT), P.O. Box 3640, D-76021, Karlsruhe, Germany
| | - Stefano Passerini
- Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, D-89081, Ulm, Germany
- Karlsruhe Institute of Technology (KIT), P.O. Box 3640, D-76021, Karlsruhe, Germany
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3
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Su L, Gao X, Mariani A, Liu X, Passerini S, Gao Y, Zheng L. Molecular Insight into Microstructural and Dynamical Heterogeneities in Magnesium Ionic Liquid Electrolytes. J Phys Chem Lett 2022; 13:105-111. [PMID: 34962126 DOI: 10.1021/acs.jpclett.1c03605] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Ionic liquids (ILs) are promising designer solvents for multivalent electrolytes, enabling the modulation of molecular-level interactions of solvate species. The molecular mechanism of multivalent-ion clustering and its impact on electrolytes properties is far less studied than that of ion pairs. Herein, we explore the effect of ion clusters on the transport and electrochemical behavior of IL-based electrolytes for Mg batteries. Simulation and small-angle X-ray scattering results indicate that ILs with higher denticity effectively suppress ion agglomeration and parasitic reactions of the Mg electrolytes. Although ion clustering reduces the diffusivity of Mg2+, the Coulombic efficiency for the reversible Mg deposition/stripping process is improved, highlighting the importance of microstructural and dynamical heterogeneities in the rational design of enhanced multivalent electrolytes.
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Affiliation(s)
- Long Su
- Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan, 250100, P. R. China
| | - Xinpei Gao
- Key Laboratory of Ministry of Education for Advanced Materials in Tropical Island Resources, Hainan University, No 58, Renmin Avenue, Haikou 570228, P. R. China
| | - Alessandro Mariani
- Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, 89081 Ulm, Germany
- Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Xu Liu
- Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, 89081 Ulm, Germany
- Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Stefano Passerini
- Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, 89081 Ulm, Germany
- Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Yanan Gao
- Key Laboratory of Ministry of Education for Advanced Materials in Tropical Island Resources, Hainan University, No 58, Renmin Avenue, Haikou 570228, P. R. China
| | - Liqiang Zheng
- Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan, 250100, P. R. China
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Yanase K, Tran KVB, Yamaguchi T, Machida H, Norinaga K. Fluctuation in diethylene glycol diethyl ether/water mixtures near the lower critical solution temperature studied by small- and wide-angle x-ray scattering and thermodynamic calculation. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.117830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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5
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Ausín D, Parajó JJ, Trenzado JL, Varela LM, Cabeza O, Segade L. Influence of Small Quantities of Water on the Physical Properties of Alkylammonium Nitrate Ionic Liquids. Int J Mol Sci 2021; 22:7334. [PMID: 34298957 PMCID: PMC8306069 DOI: 10.3390/ijms22147334] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/28/2021] [Accepted: 07/02/2021] [Indexed: 11/16/2022] Open
Abstract
This paper presents a comprehensive study of two alkylammonium nitrate ionic liquids. As part of this family of materials, mainly ethylammonium nitrate (EAN) and also propylammonium nitrate (PAN) have attracted a great deal of attention during the last decades due to their potential applications in many fields. Although there have been numerous publications focused on the measurement of their physical properties, a great dispersion can be observed in the results obtained for the same magnitude. One of the critical points to be taken into account in their physical characterization is their water content. Thus, the main objective of this work was to determine the degree of influence of the presence of small quantities of water in EAN and PAN on the measurement of density, viscosity, electrical conductivity, refractive index and surface tension. For this purpose, the first three properties were determined in samples of EAN and PAN with water contents below 30,000 ppm in a wide range of temperatures, between 5 and 95 °C, while the last two were obtained at 25 °C. As a result of this study, it has been concluded that the presence of water is critical in those physical properties that involve mass or charge transport processes, resulting in the finding that the absolute value of the average percentage change in both viscosity and electrical conductivity is above 40%. Meanwhile, refractive index (≤0.3%), density (≤0.5%) and surface tension (≤2%) present much less significant changes.
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Affiliation(s)
- David Ausín
- Departamento de Física, Facultade de Ciencias, Campus da Zapateira, Universidade da Coruña, 15071 A Coruña, Spain; (D.A.); (O.C.)
| | - Juan J. Parajó
- Grupo de Nanomateriais, Fotónica e Materia Branda, Departamento de Física de Partículas y Departamento de Física Aplicada, Universidade de Santiago de Compostela, Campus Vida s/n, 15782 Santiago de Compostela, Spain; (J.J.P.); (L.M.V.)
- Departamento de Química e Bioquímica, CIQUP-Centro de Investigaçao em Química da Universidade do Porto, Universidade do Porto, P-4169-007 Porto, Portugal
| | - José L. Trenzado
- Departamento de Física, Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas Gran Canaria, Spain;
| | - Luis M. Varela
- Grupo de Nanomateriais, Fotónica e Materia Branda, Departamento de Física de Partículas y Departamento de Física Aplicada, Universidade de Santiago de Compostela, Campus Vida s/n, 15782 Santiago de Compostela, Spain; (J.J.P.); (L.M.V.)
| | - Oscar Cabeza
- Departamento de Física, Facultade de Ciencias, Campus da Zapateira, Universidade da Coruña, 15071 A Coruña, Spain; (D.A.); (O.C.)
| | - Luisa Segade
- Departamento de Física, Facultade de Ciencias, Campus da Zapateira, Universidade da Coruña, 15071 A Coruña, Spain; (D.A.); (O.C.)
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6
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Mariani A, Bonomo M, Gao X, Centrella B, Nucara A, Buscaino R, Barge A, Barbero N, Gontrani L, Passerini S. The unseen evidence of Reduced Ionicity: The elephant in (the) room temperature ionic liquids. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.115069] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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7
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Kashin A, Degtyareva ES, Ananikov VP. Visualization of the Mechanical Wave Effect on Liquid Microphases and Its Application for the Tuning of Dissipative Soft Microreactors. JACS AU 2021; 1:87-97. [PMID: 34467272 PMCID: PMC8395697 DOI: 10.1021/jacsau.0c00024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Indexed: 05/08/2023]
Abstract
The development of approaches for creation of adaptive and stimuli-responsive chemical systems is particularly important for chemistry, materials science, and biotechnology. The understanding of response mechanisms for various external forces is highly demanded for the rational design of task-specific systems. Here, we report direct liquid-phase scanning electron microscopy (SEM) observations of the high frequency sound-wave-driven restructuring of liquid media on the microlevel, leading to switching of its chemical behavior. We show that under the action of ultrasound, the microstructured ionic liquid/water mixture undergoes rearrangement resulting in formation of separated phases with specific compositions and reactivities. The observed effect was successfully utilized for creation of dissipative soft microreactors formed in ionic liquid/water media during the sonication-driven water transfer. The performance of the microreactors was demonstrated using the example of controlled synthesis of small and uniform gold and palladium nanoparticles. The microsonication stage, designed and used in the present study, opened unique opportunities for direct sonochemical studies with the use of electron microscopy.
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Engelbrecht LDV, Farris R, Vasiliu T, Demurtas M, Piras A, Cesare Marincola F, Laaksonen A, Porcedda S, Mocci F. Theoretical and Experimental Study of the Excess Thermodynamic Properties of Highly Nonideal Liquid Mixtures of Butanol Isomers + DBE. J Phys Chem B 2021; 125:587-600. [PMID: 33428423 DOI: 10.1021/acs.jpcb.0c10076] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Binary alcohol + ether liquid mixtures are of significant importance as potential biofuels or additives for internal combustion engines and attract considerable fundamental interest as model systems containing one strongly H-bonded self-associating component (alcohol) and one that is unable to do so (ether), but that can interact strongly as a H-bond acceptor. In this context, the excess thermodynamic properties of these mixtures, specifically the excess molar enthalpies and volumes (HE and VE), have been extensively measured. Butanol isomer + di-n-butyl ether (DBE) mixtures received significant attention because of interesting differences in their VE, changing from negative (1- and isobutanol) to positive (2- and tert-butanol) with increasing alkyl group branching. With the aim of shedding light on the differences in alcohol self-association and cross-species H-bonding, considered responsible for the observed differences, we studied representative 1- and 2-butanol + DBE mixtures by molecular dynamics simulations and experimental excess property measurements. The simulations reveal marked differences in the self-association of the two isomers and, while supporting the existing interpretations of the HE and VE in a general sense, our results suggest, for the first time, that subtle changes in H-bonded topologies may contribute significantly to the anomalous volumetric properties of these mixtures.
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Affiliation(s)
- Leon de Villiers Engelbrecht
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Riccardo Farris
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Tudor Vasiliu
- Centre of Advanced Research in Bio-nanoconjugates and Biopolymers, Romanian Academy-Petru Poni (PP) Institute of Macromolecular Chemistry, 00487 Iasi, Romania
| | - Monica Demurtas
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Alessandra Piras
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Flaminia Cesare Marincola
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Aatto Laaksonen
- Centre of Advanced Research in Bio-nanoconjugates and Biopolymers, Romanian Academy-Petru Poni (PP) Institute of Macromolecular Chemistry, 00487 Iasi, Romania.,Department of Materials and Environmental Chemistry, Division of Physical Chemistry, Arrhenius Laboratory, Stockholm University (SU), 106 91 Stockholm, Sweden.,State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University (NTU), 210009 Nanjing, China.,Department of Engineering Sciences and Mathematics, Division of Energy Science, Luleå University of Technology, SE-97187 Luleå, Sweden
| | - Silvia Porcedda
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Francesca Mocci
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
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9
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Wang YL, Li B, Sarman S, Mocci F, Lu ZY, Yuan J, Laaksonen A, Fayer MD. Microstructural and Dynamical Heterogeneities in Ionic Liquids. Chem Rev 2020; 120:5798-5877. [PMID: 32292036 PMCID: PMC7349628 DOI: 10.1021/acs.chemrev.9b00693] [Citation(s) in RCA: 197] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Indexed: 12/11/2022]
Abstract
Ionic liquids (ILs) are a special category of molten salts solely composed of ions with varied molecular symmetry and charge delocalization. The versatility in combining varied cation-anion moieties and in functionalizing ions with different atoms and molecular groups contributes to their peculiar interactions ranging from weak isotropic associations to strong, specific, and anisotropic forces. A delicate interplay among intra- and intermolecular interactions facilitates the formation of heterogeneous microstructures and liquid morphologies, which further contributes to their striking dynamical properties. Microstructural and dynamical heterogeneities of ILs lead to their multifaceted properties described by an inherent designer feature, which makes ILs important candidates for novel solvents, electrolytes, and functional materials in academia and industrial applications. Due to a massive number of combinations of ion pairs with ion species having distinct molecular structures and IL mixtures containing varied molecular solvents, a comprehensive understanding of their hierarchical structural and dynamical quantities is of great significance for a rational selection of ILs with appropriate properties and thereafter advancing their macroscopic functionalities in applications. In this review, we comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.
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Affiliation(s)
- Yong-Lei Wang
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Bin Li
- School
of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, P. R. China
| | - Sten Sarman
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Francesca Mocci
- Department
of Chemical and Geological Sciences, University
of Cagliari, I-09042 Monserrato, Italy
| | - Zhong-Yuan Lu
- State
Key Laboratory of Supramolecular Structure and Materials, Institute
of Theoretical Chemistry, Jilin University, Changchun 130021, P. R. China
| | - Jiayin Yuan
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Aatto Laaksonen
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
- State
Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China
- Centre of
Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry Aleea Grigore Ghica-Voda, 41A, 700487 Iasi, Romania
- Department
of Engineering Sciences and Mathematics, Division of Energy Science, Luleå University of Technology, SE-97187 Luleå, Sweden
| | - Michael D. Fayer
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
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10
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Warr GG, Atkin R. Solvophobicity and amphiphilic self-assembly in neoteric and nanostructured solvents. Curr Opin Colloid Interface Sci 2020. [DOI: 10.1016/j.cocis.2019.12.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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11
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Statistic-Driven Proton Transfer Affecting Nanoscopic Organization in an Ethylammonium Nitrate Ionic Liquid and 1,4-Diaminobutane Binary Mixture: A Steamy Pizza Model. Symmetry (Basel) 2019. [DOI: 10.3390/sym11111425] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Herein, we report on the theoretical and experimental investigation of the chemical equilibrium in a Ethylammonium Nitrate (EAN)/1,4-Diaminobutane (DAB) binary mixture displaying a significant excess of the latter component (namely, a 1:9 mole ratio). Both the neutral compounds, i.e., ethylamine (EtNH2) and DAB, present very similar chemical properties, especially concerning their basic strength, resulting in a continuous jump of the proton from the ethylammonium to the diamine (and vice-versa). Due to the significant excess of DAB, the proton is (statistically) expected to be bound to one of its nitrogen atoms, leading to the formation of a new (ternary) mixture containing DAB (ca. 80%), ethylamine (ca. 10%) and 4-amino-1-butylammonium nitrate (ABAN, ca. 10%). This is probed by means of SAXS measurements, showing LqE (low q excess) that increases over time. This feature tends to stabilize after approximately one day. When the measurement is repeated after one year, the LqE feature shows an increased intensity. Based on the results of our simulations, we suggest that this phenomenon is likely due to partial ethylamine evaporation, pushing the equilibrium toward the formation of ABAN.
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12
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Engelbrecht L, Mocci F, Laaksonen A, Koch KR. 195Pt NMR and Molecular Dynamics Simulation Study of the Solvation of [PtCl 6] 2- in Water-Methanol and Water-Dimethoxyethane Binary Mixtures. Inorg Chem 2018; 57:12025-12037. [PMID: 30215514 DOI: 10.1021/acs.inorgchem.8b01554] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The experimental 195Pt NMR chemical shift, δ(195Pt), of the [PtCl6]2- anion dissolved in binary mixtures of water and a fully miscible organic solvent is extremely sensitive to the composition of the mixture at room temperature. Significantly nonlinear δ(195Pt) trends as a function of solvent composition are observed in mixtures of water-methanol, or ethylene glycol, 2-methoxyethanol, and 1,2-dimethoxyethane (DME). The extent of the deviation from linearity of the δ(195Pt) trend depends strongly on the nature of the organic component in these solutions, which broadly suggests preferential solvation of the [PtCl6]2- anion by the organic molecule. This simplistic interpretation is based on an accepted view pertaining to monovalent cations in similar binary solvent mixtures. To elucidate these phenomena in detail, classical molecular dynamics computer simulations were performed for [PtCl6]2- in water-methanol and water-DME mixtures using the anionic charge scaling approach to account for the effect of electronic dielectric screening. Our simulations suggest that the simplistic model of preferential solvation of [PtCl6]2- by the organic component as inferred from nonlinear δ(195Pt) trends is not entirely accurate, particularly for water-DME mixtures. The δ(195Pt) trend in these mixtures levels off for high DME mole fractions, which results from apparent preferential location of [PtCl6]2- anions at the borders of water-rich regions or clusters within these inherently micro-heterogeneous mixtures. By contrast in water-methanol mixtures, apparently less pronounced mixed solvent micro-heterogeneity is found, suggesting the experimental δ(195Pt) trend is consistent with a more moderate preferential solvation of [PtCl6]2- anions. This finding underlines the important role of solvent-solvent interactions and micro-heterogeneity in determining the solvation environment of [PtCl6]2- anions in binary solvent mixtures, probed by highly sensitive 195Pt NMR. The notion that preferential solvation of [PtCl6]2- results primarily from competing ion-solvent interactions as generally assumed for monatomic ions, may not be appropriate in general.
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Affiliation(s)
- Leon Engelbrecht
- Department of Chemistry and Polymer Science , Stellenbosch University , Private Bag X1 , Matieland 7602 , South Africa.,Department of Chemical and Geological Sciences , University of Cagliari , I-09042 Monserrato , Italy.,Division of Physical Chemistry, Department of Materials and Environmental Chemistry, Arrhenius Laboratory , Stockholm University , 10691 Stockholm , Sweden
| | - Francesca Mocci
- Department of Chemical and Geological Sciences , University of Cagliari , I-09042 Monserrato , Italy
| | - Aatto Laaksonen
- Division of Physical Chemistry, Department of Materials and Environmental Chemistry, Arrhenius Laboratory , Stockholm University , 10691 Stockholm , Sweden.,Department of Chemistry-Ångström Laboratory , Uppsala University , Box 538, SE-75121 Uppsala , Sweden
| | - Klaus R Koch
- Department of Chemistry and Polymer Science , Stellenbosch University , Private Bag X1 , Matieland 7602 , South Africa
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Structures of binary mixtures of ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide with primary alcohols: The role of hydrogen-bonding. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.03.124] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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14
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Campetella M, Mariani A, Sadun C, Wu B, Castner EW, Gontrani L. Structure and dynamics of propylammonium nitrate-acetonitrile mixtures: An intricate multi-scale system probed with experimental and theoretical techniques. J Chem Phys 2018; 148:134507. [PMID: 29626911 DOI: 10.1063/1.5021868] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In this article, we report the study of structural and dynamical properties for a series of acetonitrile/propylammonium nitrate mixtures as a function of their composition. These systems display an unusual increase in intensity in their X-ray diffraction patterns in the low-q regime, and their 1H-NMR diffusion-ordered NMR spectroscopy (DOSY) spectra display unusual diffusivities. However, the magnitude of both phenomena for mixtures of propylammonium nitrate is smaller than those observed for ethylammonium nitrate mixtures with the same cosolvent, suggesting that the cation alkyl tail plays an important role in these observations. The experimental X-ray scattering data are compared with the results of molecular dynamics simulations, including both ab initio studies used to interpret short-range interactions and classical simulations to describe longer range interactions. The higher level calculations highlight the presence of a strong hydrogen bond network within the ionic liquid, only slightly perturbed even at high acetonitrile concentration. These strong interactions lead to the symmetry breaking of the NO3- vibrations, with a splitting of about 88 cm-1 in the ν3 antisymmetric stretch. The classical force field simulations use a greater number of ion pairs, but are not capable of fully describing the longest range interactions, although they do successfully account for the observed concentration trend, and the analysis of the models confirms the nano-inhomogeneity of these kinds of samples.
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Affiliation(s)
- Marco Campetella
- Institut de Recherche de Chimie Paris, CNRS, PSL Research University, Chimie ParisTech, F-75005 Paris, France
| | - Alessandro Mariani
- Beamline ID02, ESRF-European Synchrotron Radiation Facility, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - Claudia Sadun
- Università degli Studi di Roma "La Sapienza," P. le Aldo Moro 5, I-00185 Roma, Italy
| | - Boning Wu
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey 08854, USA
| | - Edward W Castner
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey 08854, USA
| | - Lorenzo Gontrani
- Università degli Studi di Roma "La Sapienza," P. le Aldo Moro 5, I-00185 Roma, Italy
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Mariani A, Bonomo M, Wu B, Centrella B, Dini D, Castner EW, Gontrani L. Intriguing transport dynamics of ethylammonium nitrate-acetonitrile binary mixtures arising from nano-inhomogeneity. Phys Chem Chem Phys 2018; 19:27212-27220. [PMID: 28975937 DOI: 10.1039/c7cp04592a] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Binary mixtures of ethylammonium nitrate and acetonitrile show interesting properties that originate from the structural and dynamical nano-heterogeneity present in ionic liquids. These effects are most pronounced when the ionic liquid is the minority compound. In this study the transport properties of such mixtures are studied, including viscosity, self-diffusion and conductivity. The results strongly support the presence of structural inhomogeneity and show an interesting composition-dependent behaviour in the mixtures.
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Affiliation(s)
- Alessandro Mariani
- Department of Chemistry, La Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy.
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