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R de Moraes B, Paschoal VH, Keppeler N, El Seoud OA, Ando RA. The Coiling Effect in Ether Ionic Liquids: Exploiting Acetate as a Probe for Transport Properties and Microenvironment Analysis. J Phys Chem B 2024. [PMID: 38608137 DOI: 10.1021/acs.jpcb.3c08162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2024]
Abstract
The inherently high viscosity of ionic liquids (ILs) can limit their potential applications. One approach to address this drawback is to modify the cation side chain with ether groups. Herein, we assessed the structure-property relationship by focusing on acetate (OAc), a strongly coordinating anion, with 1,3-dialkylimidazolium cations with different side chains, including alkyl, ether, and hydroxyl functionalized, as well as their combinations. We evaluated their viscosity, thermal stabilities, and microstructure using Raman and infrared (IR) spectroscopies, allied to density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. The viscosity data showed that the ether insertion significantly enhances the fluidity of the ILs, consistent with the coiling effect of the cation chain. Through a combined experimental and theoretical approach, we analyzed how the OAc anion interacts with ether ILs, revealing a characteristic bidentate coordination, particularly in hydroxyl functionalized ILs due to specific hydrogen bonding with the OH group. IR spectroscopy showed subtle shifts in the acidic hydrogens of imidazolium ring C(2)-H and C(4,5)-H, suggesting weaker interactions between OAc and the imidazolium ring in ether-functionalized ILs. Additionally, spatial distribution functions (SDF) and dihedral angle distribution obtained via AIMD confirmed the intramolecular hydrogen bonding due to the coiling effect of the ether side chain.
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Affiliation(s)
- Beatriz R de Moraes
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo 05508-900, Brazil
| | - Vitor H Paschoal
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo 05508-900, Brazil
| | - Nicolas Keppeler
- Grupo de polímero e surfactantes, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo 05508-900, Brazil
| | - Omar A El Seoud
- Grupo de polímero e surfactantes, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo 05508-900, Brazil
| | - Rômulo A Ando
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo 05508-900, Brazil
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2
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Lass M, Kenter T, Plessl C, Brehm M. Characterizing Microheterogeneity in Liquid Mixtures via Local Density Fluctuations. ENTROPY (BASEL, SWITZERLAND) 2024; 26:322. [PMID: 38667876 PMCID: PMC11049288 DOI: 10.3390/e26040322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/04/2024] [Accepted: 04/05/2024] [Indexed: 04/28/2024]
Abstract
We present a novel approach to characterize and quantify microheterogeneity and microphase separation in computer simulations of complex liquid mixtures. Our post-processing method is based on local density fluctuations of the different constituents in sampling spheres of varying size. It can be easily applied to both molecular dynamics (MD) and Monte Carlo (MC) simulations, including periodic boundary conditions. Multidimensional correlation of the density distributions yields a clear picture of the domain formation due to the subtle balance of different interactions. We apply our approach to the example of force field molecular dynamics simulations of imidazolium-based ionic liquids with different side chain lengths at different temperatures, namely 1-ethyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, and 1-decyl-3-methylimidazolium chloride, which are known to form distinct liquid domains. We put the results into the context of existing microheterogeneity analyses and demonstrate the advantages and sensitivity of our novel method. Furthermore, we show how to estimate the configuration entropy from our analysis, and we investigate voids in the system. The analysis has been implemented into our program package TRAVIS and is thus available as free software.
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Affiliation(s)
- Michael Lass
- Faculty of Computer Science, Electrical Engineering and Mathematics, Department of Computer Science, Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany; (M.L.); (T.K.); (C.P.)
| | - Tobias Kenter
- Faculty of Computer Science, Electrical Engineering and Mathematics, Department of Computer Science, Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany; (M.L.); (T.K.); (C.P.)
| | - Christian Plessl
- Faculty of Computer Science, Electrical Engineering and Mathematics, Department of Computer Science, Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany; (M.L.); (T.K.); (C.P.)
| | - Martin Brehm
- Faculty of Science, Department of Chemistry, Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
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3
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Wylie L, Barham JP, Kirchner B. Solvent Dependency of Catalyst-Substrate Aggregation Through π-π Stacking in Photoredox Catalysis. Chemphyschem 2023; 24:e202300470. [PMID: 37477880 DOI: 10.1002/cphc.202300470] [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: 07/03/2023] [Revised: 07/21/2023] [Accepted: 07/21/2023] [Indexed: 07/22/2023]
Abstract
Assemblies of photoredox catalysts and their target substrates prior to photoexcitation is a phenomenon naïvely overlooked by the majority of synthetic chemists, but can have profound influences on reactivity and selectivity in photocatalytic reactions. In this study, we determine the aggregation states of triarylamine radical cationic photocatalysts with various target arene substrates in different solvents by specifically parameterized polarizable molecular dynamics simulations. A π-stacking interaction previously implicated by more expensive, less-representative quantum calculations is confirmed. Critically, this study presents new insights on: i) the ability of solvents (MeCN vs DMF) to make or break a photocatalytic reaction by promoting (MeCN) or demoting (DMF) its catalyst-substrate assemblies, which is a determining factor for reactivity, ii) the average "lifetimes" of assemblies in solution from a dynamic simulation. We find that both in the ground state and the photoexcited state, the cationic radical assemblies remain intact for periods often higher than 60 ps, rendering them ideally suitable to undergo intra-assembly electron transfer reactions upon photoexcitation. Such aspects have not addressed by previous studies on synthetic photocatalytic reactions involving non-covalent assemblies.
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Affiliation(s)
- Luke Wylie
- University of Bonn, Clausius Institute of Physical and Theoretical Chemistry, Mulliken Center for Theoretical Chemistry, Beringstr. 4, D-53115, Bonn, Germany
| | - Joshua P Barham
- Institute of Organic Chemistry, University of Regensburg, Universitätsstraße 31, D93053, Regensburg, Germany
| | - Barbara Kirchner
- University of Bonn, Clausius Institute of Physical and Theoretical Chemistry, Mulliken Center for Theoretical Chemistry, Beringstr. 4, D-53115, Bonn, Germany
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4
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Paschoal VH, Ribeiro MCC. DFT and ab initio molecular dynamics simulation study of the infrared spectrum of the protic ionic liquid 2-hydroxyethylammonium formate. Phys Chem Chem Phys 2023; 25:26475-26485. [PMID: 37753589 DOI: 10.1039/d3cp02914j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
Protic ionic liquids (PILs) typically show a complex band shape in their infrared (IR) spectra in the high-frequency range due to the hydrogen stretching vibrations of functional groups forming rather strong hydrogen bonds (H-bonds). In the low-frequency range, the intermolecular stretching mode of the H-bond leaves a mark in the far-IR spectrum of PILs. In this study, the IR spectrum of the PIL 2-hydroxyethylammonium formate, [HOCH2CH2NH3][HCOO], is investigated in order to identify the different modes that contribute to the high-frequency band shape, i.e. the cation ν(NH), ν(OH), and ν(CH) modes, and the anion ν(CH) mode, as well as the intermolecular mode of the strongest H-bond in the far-IR spectrum. The assignment is validated by quantum chemistry calculations of clusters at the density functional theory (DFT) level for four ionic pairs and by ab initio molecular dynamics (AIMD) simulations of ten ionic pairs. There is good agreement between the vibrational frequencies obtained from DFT and AIMD simulations for both the high- and low-frequency ranges. Based on the calculations, the strong H-bond interaction between the cation -NH3 group and [HCOO]- gives a broad band envelope associated with the ν(NH) mode in the high-frequency range of the IR spectrum on which there are narrower peaks corresponding to the ν(OH) and ν(CH) modes. In the far-IR (FIR) spectrum, the anions' rattling motion gives a broad feature with a maximum at 160 cm-1, while the H-bond's intermolecular NH⋯O stretching mode appears as a peak at 255 cm-1.
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Affiliation(s)
- Vitor Hugo Paschoal
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, 05513-970, São Paulo, SP, Brazil.
| | - Mauro C C Ribeiro
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, 05513-970, São Paulo, SP, Brazil.
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5
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Roos E, Sebastiani D, Brehm M. A force field for bio-polymers in ionic liquids (BILFF) - part 2: cellulose in [EMIm][OAc]/water mixtures. Phys Chem Chem Phys 2023; 25:8755-8766. [PMID: 36897117 DOI: 10.1039/d2cp05636d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
We present the extension of our force field BILFF (Bio-Polymers in Ionic Liquids Force Field) to the bio-polymer cellulose. We already published BILFF parameters for mixtures of ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIm][OAc]) with water. Our all-atom force field focuses on a quantitative reproduction of the hydrogen bonds in the complex mixture of cellulose, [EMIm]+, [OAc]- and water when compared to reference ab initio molecular dynamics (AIMD) simulations. To enhance the sampling, 50 individual AIMD simulations starting from different initial configurations were performed for cellulose in solvent instead of one long simulation, and the resulting averages were used for force field optimization. All cellulose force field parameters were iteratively adjusted starting from the literature force field of W. Damm et al. We were able to obtain a very good agreement with respect to both the microstructure of the reference AIMD simulations and experimental results such as the system density (even at higher temperatures) and the crystal structure. Our new force field allows performing very long simulations of large systems containing cellulose solvated in (aqueous) [EMIm][OAc] with almost ab initio accuracy.
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Affiliation(s)
- Eliane Roos
- Institut für Chemie - Theoretische Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany.
| | - Daniel Sebastiani
- Institut für Chemie - Theoretische Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany.
| | - Martin Brehm
- Institut für Chemie - Theoretische Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany.
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6
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Gousseva E, Midgley SD, Seymour JM, Seidel R, Grau-Crespo R, Lovelock KRJ. Understanding X-ray Photoelectron Spectra of Ionic Liquids: Experiments and Simulations of 1-Butyl-3-methylimidazolium Thiocyanate. J Phys Chem B 2022; 126:10500-10509. [PMID: 36455069 PMCID: PMC9761679 DOI: 10.1021/acs.jpcb.2c06372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
We demonstrate a combined experimental and computational approach to probe the electronic structure and atomic environment of an ionic liquid, based on core level binding energies. The 1-butyl-3-methylimidazolium thiocyanate [C4C1Im][SCN] ionic liquid was studied using ab initio molecular dynamics, and results were compared against previously published and new experimental X-ray photoelectron spectroscopy (XPS) data. The long-held assumption that initial-state effects in XPS dominate the measured binding energies is proven correct, which validates the established premise that the ground state electronic structure of the ionic liquid can be inferred directly from XPS measurements. A regression model based upon site electrostatic potentials and intramolecular bond lengths is shown to account accurately for variations in core-level binding energies within the ionic liquid, demonstrating the important effect of long-range interactions on the core levels and throwing into question the validity of traditional single ion pair ionic liquid calculations for interpreting XPS data.
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Affiliation(s)
| | - Scott D. Midgley
- Department
of Chemistry, University of Reading, ReadingRG6 6DX, U.K.
| | - Jake M. Seymour
- Department
of Chemistry, University of Reading, ReadingRG6 6DX, U.K.
| | - Robert Seidel
- Helmholtz-Zentrum
Berlin für Materialien und Energie (HZB), Berlin14109, Germany
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7
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Niemöller H, Blasius J, Hollóczki O, Kirchner B. How do alternative amino acids behave in water? A comparative ab initio molecular dynamics study of solvated α-amino acids and α-amino amidines. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120282] [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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8
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Frömbgen T, Blasius J, Alizadeh V, Chaumont A, Brehm M, Kirchner B. Cluster Analysis in Liquids: A Novel Tool in TRAVIS. J Chem Inf Model 2022; 62:5634-5644. [PMID: 36315975 DOI: 10.1021/acs.jcim.2c01244] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a novel cluster analysis implemented in our open-source software TRAVIS and its application to realistic and complex chemical systems. The underlying algorithm is exclusively based on atom distances. Using a two-dimensional model system, we first introduce different cluster analysis functions and their application to single snapshots and trajectories including periodicity and temporal propagation. Using molecular dynamics simulations of pure water with varying system size, we show that our cluster analysis is size-independent. Furthermore, we observe a similar clustering behavior of pure water in classical and ab initio molecular dynamics simulations, showing that our cluster analysis is universal. In order to emphasize the application to more complex systems and mixtures, we additionally apply the cluster analysis to ab initio molecular dynamics simulations of the [C2C1Im][OAc] ionic liquid and its mixture with water. Using that, we show that our cluster analysis is able to analyze the clustering of the individual components in a mixture as well as the clustering of the ionic liquid with water.
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Affiliation(s)
- Tom Frömbgen
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstraße 4+6, D-53115 Bonn, Germany
| | - Jan Blasius
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstraße 4+6, D-53115 Bonn, Germany
| | - Vahideh Alizadeh
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstraße 4+6, D-53115 Bonn, Germany
| | - Alain Chaumont
- Laboratoire MSM, UMR 7140 CNRS, Institut de Chimie, 4 Rue Blaise Pascal, F-67000 Strasbourg, France
| | - Martin Brehm
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - Barbara Kirchner
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstraße 4+6, D-53115 Bonn, Germany
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9
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Brehm M, Thomas M. Optimized Atomic Partial Charges and Radii Defined by Radical Voronoi Tessellation of Bulk Phase Simulations. Molecules 2021; 26:1875. [PMID: 33810337 PMCID: PMC8036805 DOI: 10.3390/molecules26071875] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 12/05/2022] Open
Abstract
We present a novel method for the computation of well-defined optimized atomic partial charges and radii from the total electron density. Our method is based on a two-step radical Voronoi tessellation of the (possibly periodic) system and subsequent integration of the total electron density within each Voronoi cell. First, the total electron density is partitioned into the contributions of each molecule, and subsequently the electron density within each molecule is assigned to the individual atoms using a second set of atomic radii for the radical Voronoi tessellation. The radii are optimized on-the-fly to minimize the fluctuation (variance) of molecular and atomic charges. Therefore, our method is completely free of empirical parameters. As a by-product, two sets of optimized atomic radii are produced in each run, which take into account many specific properties of the system investigated. The application of an on-the-fly interpolation scheme reduces discretization noise in the Voronoi integration. The approach is particularly well suited for the calculation of partial charges in periodic bulk phase systems. We apply the method to five exemplary liquid phase simulations and show how the optimized charges can help to understand the interactions in the systems. Well-known effects such as reduced ion charges below unity in ionic liquid systems are correctly predicted without any tuning, empiricism, or rescaling. We show that the basis set dependence of our method is very small. Only the total electron density is evaluated, and thus, the approach can be combined with any electronic structure method that provides volumetric total electron densities-it is not limited to Hartree-Fock or density functional theory (DFT). We have implemented the method into our open-source software tool TRAVIS.
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Affiliation(s)
- Martin Brehm
- Institut für Chemie, Martin-Luther-Universität Halle–Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany;
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10
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Philippi F, Welton T. Targeted modifications in ionic liquids - from understanding to design. Phys Chem Chem Phys 2021; 23:6993-7021. [PMID: 33876073 DOI: 10.1039/d1cp00216c] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ionic liquids are extremely versatile and continue to find new applications in academia as well as industry. This versatility is rooted in the manifold of possible ion types, ion combinations, and ion variations. However, to fully exploit this versatility, it is imperative to understand how the properties of ionic liquids arise from their constituents. In this work, we discuss targeted modifications as a powerful tool to provide understanding and to enable design. A 'targeted modification' is a deliberate change in the structure of an ionic liquid. This includes chemical changes in an experiment as well as changes to the parameterisation in a computer simulation. In any case, such a change must be purposeful to isolate what is of interest, studying, as far as is possible, only one concept at a time. The concepts can then be used as design elements. However, it is often found that several design elements interact with each other - sometimes synergistically, and other times antagonistically. Targeted modifications are a systematic way of navigating these overlaps. We hope this paper shows that understanding ionic liquids requires experimentalists and theoreticians to join forces and provides a tool to tackle the difficult transition from understanding to design.
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Affiliation(s)
- Frederik Philippi
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, London W12 0BZ, UK.
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11
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Roos E, Brehm M. A force field for bio-polymers in ionic liquids (BILFF) - part 1: [EMIm][OAc]/water mixtures. Phys Chem Chem Phys 2021; 23:1242-1253. [PMID: 33355320 DOI: 10.1039/d0cp04537c] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present BILFF, a novel force field for bio-polymers in ionic liquids. In the first part of our study, we introduce optimized force field parameters for mixtures of the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([EMIm][OAc]) with water. This imidazolium-based IL is of particular practical importance as it can dissolve significant amounts of cellulose even at room temperature. An understanding of this dissolution process via molecular dynamics simulations requires a quantitative description of the microscopic structure and the strong hydrogen bonds with a method able of simulating at least several dozen nanoseconds, which is the main aim of our novel force field. To reach this goal, we optimize the force field parameters to reproduce radial, spatial, and combined distribution functions, hydrogen bond lifetimes, diffusion coefficients, and several other quantities from reference ab initio molecular dynamics (AIMD) simulations. Non-trivial effects such as dispersion interactions between the side chains and π-π stacking of the cations are reproduced very well. We further validate the force field by comparison to experimental data such as thermal expansion coefficients, bulk modulus, and density at different temperatures, which yields good agreement and correct trends. No other force field with optimized parameters for mixtures of [EMIm][OAc] and water has been presented in the literature yet. Optimized force field parameters for cellulose and other ILs will be published in upcoming articles.
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Affiliation(s)
- Eliane Roos
- Institut für Chemie - Theoretische Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany.
| | - Martin Brehm
- Institut für Chemie - Theoretische Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany.
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12
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Torkzadeh M, Moosavi M. Probing the Effect of Side Alkyl Chain Length on the Structural and Dynamical Micro-heterogeneities in Dicationic Ionic Liquids. J Phys Chem B 2020; 124:11446-11462. [PMID: 33283503 DOI: 10.1021/acs.jpcb.0c07034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The molecular dynamics simulations and Voronoi tessellation analysis of two dicationic ionic liquids (DILs) including [C5(mim)2][NTf2]2 and [C5(mim)2C4][NTf2]2 have been carried out to investigate the effects of side alkyl chain length on the structural and dynamical micro-heterogeneity of these DILs. Radial distribution functions (RDFs), spatial distribution functions (SDFs), and also neighborhood analysis of ions have been calculated to determine the arrangement of the nearest neighboring ions. To better understand the hydrogen-bonding network, microstructures, inter- and intramolecular orientations of ions in the studied DILs, different kinds of combined distribution functions (CDFs) were computed and analyzed. Also, qualitative and quantitative analyses of the structural heterogeneity were explored through total/partial structure factors, heterogeneity order parameters (HOPs), and domain analysis from Voronoi tessellation. The results showed that the side alkyl chains in DILs have significant effects on their micro-organizations in such a way that [C5(mim)2C4][NTf2]2 with longer side chains has more microstructural heterogeneity than [C5(mim)2][NTf2]2 where the linkage alkyl chain is the same in both of them. Furthermore, to shed light on the dynamical heterogeneity, ion pair, ion cage, and hydrogen-bond stabilities and also the reorientation dynamics of ions have been investigated. Results demonstrated that local dynamics differences originate from local structural heterogeneity.
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Affiliation(s)
| | - Majid Moosavi
- Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran
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13
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Weiß M, Brehm M. Exploring Free Energy Profiles of Enantioselective Organocatalytic Aldol Reactions under Full Solvent Influence. Molecules 2020; 25:E5861. [PMID: 33322424 PMCID: PMC7764805 DOI: 10.3390/molecules25245861] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/05/2020] [Accepted: 12/08/2020] [Indexed: 12/29/2022] Open
Abstract
We present a computational study on the enantioselectivity of organocatalytic proline-catalyzed aldol reactions between aldehydes in dimethylformamide (DMF). To explore the free energy surface of the reaction, we apply two-dimensional metadynamics on top of ab initio molecular dynamics (AIMD) simulations with explicit solvent description on the DFT level of theory. We avoid unwanted side reactions by utilizing our newly developed hybrid AIMD (HyAIMD) simulation scheme, which adds a simple force field to the AIMD simulation to prevent unwanted bond breaking and formation. Our condensed phase simulation results are able to nicely reproduce the experimental findings, including the main stereoisomer that is formed, and give a correct qualitative prediction of the change in syn:anti product ratio with different substituents. Furthermore, we give a microscopic explanation for the selectivity. We show that both the explicit description of the solvent and the inclusion of entropic effects are vital to a good outcome-metadynamics simulations in vacuum and static nudged elastic band (NEB) calculations yield significantly worse predictions when compared to the experiment. The approach described here can be applied to a plethora of other enantioselective or organocatalytic reactions, enabling us to tune the catalyst or determine the solvent with the highest stereoselectivity.
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Affiliation(s)
| | - Martin Brehm
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany;
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14
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Brehm M, Radicke J, Pulst M, Shaabani F, Sebastiani D, Kressler J. Dissolving Cellulose in 1,2,3-Triazolium- and Imidazolium-Based Ionic Liquids with Aromatic Anions. Molecules 2020; 25:E3539. [PMID: 32748878 PMCID: PMC7435399 DOI: 10.3390/molecules25153539] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 11/16/2022] Open
Abstract
We present 1,2,3-triazolium- and imidazolium-based ionic liquids (ILs) with aromatic anions as a new class of cellulose solvents. The two anions in our study, benzoate and salicylate, possess a lower basicity when compared to acetate and therefore should lead to a lower amount of N-heterocyclic carbenes (NHCs) in the ILs. We characterize their physicochemical properties and find that all of them are liquids at room temperature. By applying force field molecular dynamics (MD) simulations, we investigate the structure and dynamics of the liquids and find strong and long-lived hydrogen bonds, as well as significant π-π stacking between the aromatic anion and cation. Our ILs dissolve up to 8.5 wt.-% cellulose. Via NMR spectroscopy of the solution, we rule out chain degradation or derivatization, even after several weeks at elevated temperature. Based on our MD simulations, we estimate the enthalpy of solvation and derive a simple model for semi-quantitative prediction of cellulose solubility in ILs. With the help of Sankey diagrams, we illustrate the hydrogen bond network topology of the solutions, which is characterized by competing hydrogen bond donors and acceptors. The hydrogen bonds between cellulose and the anions possess average lifetimes in the nanosecond range, which is longer than found in common pure ILs.
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Affiliation(s)
- Martin Brehm
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle, Germany
| | - Julian Radicke
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle, Germany
| | - Martin Pulst
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle, Germany
| | - Farzaneh Shaabani
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle, Germany
| | - Daniel Sebastiani
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle, Germany
| | - Jörg Kressler
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle, Germany
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15
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Are There Magic Compositions in Deep Eutectic Solvents? Effects of Composition and Water Content in Choline Chloride/Ethylene Glycol from Ab Initio Molecular Dynamics. J Phys Chem B 2020; 124:7433-7443. [DOI: 10.1021/acs.jpcb.0c04844] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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16
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Blasius J, Elfgen R, Hollóczki O, Kirchner B. Glucose in dry and moist ionic liquid: vibrational circular dichroism, IR, and possible mechanisms. Phys Chem Chem Phys 2020; 22:10726-10737. [PMID: 32150178 DOI: 10.1039/c9cp06798a] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ionic liquids and their mixtures with water show remarkable features in cellulose processing. For this reason, understanding the behavior of carbohydrates in ionic liquids is important. In the present study, we investigated three d-glucose isomers (α, β and open-chain) in 1-ethyl-3-methylimidazolium acetate in the presence and absence of water, through ab initio molecular dynamics simulations. In the complex hydrogen bonding network of these mixtures, the most interesting observation is that upon water addition every hydrogen bond elongates, except the glucose-glucose hydrogen bond for the open-chain and the α-form which shortens, clearly showing the beginning of the crystallization process. The ring glucose rearranges from on-top to in-plane and the open form changes from a coiled to a more linear arrangement when adding water which explains the contradiction that the center of mass distances of the glucose molecules with other glucose molecules grow while the hydrogen bonds shorten. The appearance of coiled open forms indicates that the previously suggested isomerization between these forms is possible and might play a role in the solubility of the related carbohydrates. The calculated IR and VCD spectra reveal insight into the intermolecular interactions, with good to excellent agreements with experimental spectra. Investigating the role of the cation, distances between the acidic carbon atom of the cation and the glucose carbon atom where ring closure and opening occurs are found, which are way shorter than dispersion-like interactions between aliphatic hydrocarbons.
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Affiliation(s)
- Jan Blasius
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstraße 4 + 6, D-53115 Bonn, Germany.
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17
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Brehm M, Thomas M, Gehrke S, Kirchner B. TRAVIS—A free analyzer for trajectories from molecular simulation. J Chem Phys 2020; 152:164105. [DOI: 10.1063/5.0005078] [Citation(s) in RCA: 164] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- M. Brehm
- Institut für Chemie, Martin-Luther-Universität Halle–Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - M. Thomas
- Institut für Chemie, Martin-Luther-Universität Halle–Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - S. Gehrke
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4+6, D-53115 Bonn, Germany
| | - B. Kirchner
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4+6, D-53115 Bonn, Germany
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18
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Koverga VA, Smortsova Y, Miannay FA, Kalugin ON, Takamuku T, Jedlovszky P, Marekha B, Cordeiro MNDS, Idrissi A. Distance Angle Descriptors of the Interionic and Ion-Solvent Interactions in Imidazolium-Based Ionic Liquid Mixtures with Aprotic Solvents: A Molecular Dynamics Simulation Study. J Phys Chem B 2019; 123:6065-6075. [PMID: 31179700 DOI: 10.1021/acs.jpcb.9b03838] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aim of this paper is to quantify the changes of the interionic and ion-solvent interactions in mixtures of imidazolium-based ionic liquids, having tetrafluoroborate (BmimBF4), hexafluorophosphate (BmimPF6), trifluoromethylsulfonate (BmimTFO), or bis(trifluoromethanesulfonyl)imide (BmimTFSI), anions, and polar aprotic molecular solvents, such as acetonitrile (AN), γ-butyrolactone (GBL), and propylene carbonate (PC). For this purpose, we calculate, using the nearest-neighbor approach, the average distance between the imidazolium ring H atom in positions 2, 4, and 5 (H2,4,5) and the nearest high-electronegativity atom of the solvent or anion (X) as distance descriptors, and the mean angle formed by the C2,4,5-H2,4,5 bond and the H2,4,5···X axis around the H2,4,5 atom as angular descriptors of the cation-anion and cation-solvent interactions around the ring C-H groups. The behavior of these descriptors as a function of the ionic liquid mole fraction is analyzed in detail. The obtained results show that the extent of the change of these descriptors with respect to their values in the neat ionic liquid depends both on the nature of the anion and on the mixture composition. Thus, in the case of the mixtures of the molecular solvents with BmimBF4 and BmimTFO, a small change of the distance and a drastic increase of the angular descriptor corresponding to the cation-anion interactions are observed with decreasing mole fraction of the ionic liquid, indicating that the anion moves from the above/below position (with respect to the imidazolium ring plane) to a position that is nearly linearly aligned with the C2-H2 bond and hinders the possible interaction between the C2-H2 group and the solvent molecules. On the other hand, in the case of mixtures of BmimTFSI and BmimPF6 with the molecular solvents, both the observed increase of the distance descriptor and the slight change of the angular descriptor with decreasing ionic liquid mole fraction are compatible with the direct interactions of the solvent with the C2-H2 group. The behavior of these descriptors is correlated with the experimentally observed 1H chemical shift of the C2-H2 group and the red shift of the C2-H2 vibrational mode, particularly at low ionic liquid mole fractions. The present results are thus of great help in interpreting these experimental observations.
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Affiliation(s)
- Volodymyr A Koverga
- Univ. Lille, CNRS, UMR 8516-LASIR-Laboratoire de Spectrochimie Infrarouge et Raman , F-59000 Lille , France.,Department of Inorganic Chemistry , V.N. Karazin Kharkiv National University , Svoboda sq. 4 , Kharkiv 61022 , Ukraine.,LAQV@REQUIMTE, Faculty of Sciences, Department of Chemistry and Biochemistry , University of Porto , Rua do Campo Alegre , 4169-007 Porto , Portugal
| | - Yevheniia Smortsova
- Univ. Lille, CNRS, UMR 8516-LASIR-Laboratoire de Spectrochimie Infrarouge et Raman , F-59000 Lille , France
| | - François Alexandre Miannay
- Univ. Lille, CNRS, UMR 8516-LASIR-Laboratoire de Spectrochimie Infrarouge et Raman , F-59000 Lille , France
| | - Oleg N Kalugin
- Department of Inorganic Chemistry , V.N. Karazin Kharkiv National University , Svoboda sq. 4 , Kharkiv 61022 , Ukraine
| | - Toshiyuki Takamuku
- Department of Chemistry and Applied Chemistry, Faculty of Science and Engineering , Saga University , Honjo-machi, Saga 840-8502 , Japan
| | - Pal Jedlovszky
- Department of Chemistry , Eszterházy Károly University , Leányka utca 6 , H-3300 Eger , Hungary
| | - Bogdan Marekha
- Molecular Spectroscopy Department , Max Planck Institute for Polymer Research , 10 Ackermannweg , 55128 Mainz , Germany
| | - M Natalia D S Cordeiro
- LAQV@REQUIMTE, Faculty of Sciences, Department of Chemistry and Biochemistry , University of Porto , Rua do Campo Alegre , 4169-007 Porto , Portugal
| | - Abdenacer Idrissi
- Univ. Lille, CNRS, UMR 8516-LASIR-Laboratoire de Spectrochimie Infrarouge et Raman , F-59000 Lille , France
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19
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Brehm M, Pulst M, Kressler J, Sebastiani D. Triazolium-Based Ionic Liquids: A Novel Class of Cellulose Solvents. J Phys Chem B 2019; 123:3994-4003. [DOI: 10.1021/acs.jpcb.8b12082] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Martin Brehm
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - Martin Pulst
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - Jörg Kressler
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - Daniel Sebastiani
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
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20
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Brehm M, Sebastiani D. Simulating structure and dynamics in small droplets of 1-ethyl-3-methylimidazolium acetate. J Chem Phys 2018; 148:193802. [PMID: 30307180 DOI: 10.1063/1.5010342] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
To investigate the structure and dynamics of small ionic liquid droplets in gas phase, we performed a DFT-based ab initio molecular dynamics study of several 1-ethyl-3-methylimidazolium acetate clusters in vacuum as well as a bulk phase simulation. We introduce an unbiased criterion for average droplet diameter and density. By extrapolation of the droplet densities, we predict the experimental bulk phase density with a deviation of only a few percent. The hydrogen bond geometry between cations and anions is very similar in droplets and bulk, but the hydrogen bond dynamics is significantly slower in the droplets, becoming slower with increasing system size, with hydrogen bond lifetimes up to 2000 ps. From a normal mode analysis of the trajectories, we identify the modes of the ring proton C-H stretching, which are strongly affected by hydrogen bonding. From analyzing these, we find that the hydrogen bond becomes weaker with increasing system size. The cations possess an increased concentration inside the clusters, whereas the anions show an excess concentration on the outside. Almost all anions point towards the droplet center with their carboxylic groups. Ring stacking is found to be a very important structural motif in the droplets (as in the bulk), but side chain interactions are only of minor importance. By using Voronoi tessellation, we define the exposed droplet surface and find that it consists mainly of hydrogen atoms from the cation's and anion's methyl and ethyl groups. Polar atoms are rarely found on the surface, such that the droplets appear completely hydrophobic on the outside.
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Affiliation(s)
- Martin Brehm
- Institut für Chemie-Theoretische Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Daniel Sebastiani
- Institut für Chemie-Theoretische Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
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21
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Perlt E, Ray P, Hansen A, Malberg F, Grimme S, Kirchner B. Finding the best density functional approximation to describe interaction energies and structures of ionic liquids in molecular dynamics studies. J Chem Phys 2018; 148:193835. [PMID: 30307237 DOI: 10.1063/1.5013122] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ionic liquids raise interesting but complicated questions for theoretical investigations due to the fact that a number of different inter-molecular interactions, e.g., hydrogen bonding, long-range Coulomb interactions, and dispersion interactions, need to be described properly. Here, we present a detailed study on the ionic liquids ethylammonium nitrate and 1-ethyl-3-methylimidazolium acetate, in which we compare different dispersion corrected density functional approximations to accurate local coupled cluster data in static calculations on ionic liquid clusters. The efficient new composite method B97-3c is tested and has been implemented in CP2K for future studies. Furthermore, tight-binding based approaches which may be used in large scale simulations are assessed. Subsequently, ab initio as well as classical molecular dynamics simulations are conducted and structural analyses are presented in order to shed light on the different short- and long-range structural patterns depending on the method and the system size considered in the simulation. Our results indicate the presence of strong hydrogen bonds in ionic liquids as well as the aggregation of alkyl side chains due to dispersion interactions.
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Affiliation(s)
- Eva Perlt
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstr. 4, D-53115 Bonn, Germany
| | - Promit Ray
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstr. 4, D-53115 Bonn, Germany
| | - Andreas Hansen
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstr. 4, D-53115 Bonn, Germany
| | - Friedrich Malberg
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstr. 4, D-53115 Bonn, Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstr. 4, D-53115 Bonn, Germany
| | - Barbara Kirchner
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstr. 4, D-53115 Bonn, Germany
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22
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Brehm M, Thomas M. An Efficient Lossless Compression Algorithm for Trajectories of Atom Positions and Volumetric Data. J Chem Inf Model 2018; 58:2092-2107. [PMID: 30223650 DOI: 10.1021/acs.jcim.8b00501] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present our newly developed and highly efficient lossless compression algorithm for trajectories of atom positions and volumetric data. The algorithm is designed as a two-step approach. In the first step, efficient polynomial extrapolation schemes reduce the information entropy of the data by exploiting both spatial and temporal continuity. The second step processes the data by a series of transformations (Burrows-Wheeler, move-to-front, run length encoding) and finally compresses the stream with multitable canonical Huffman coding. Our approach reaches a compression ratio of around 15:1 for typical position trajectories in the XYZ format. For volumetric data trajectories in Gaussian Cube format (such as electron density), even a compression ratio of around 35:1 is yielded, which is by far the smallest size of all formats compared here. At the same time, compression and decompression are still reasonably fast for everyday use. The precision of the data can be selected by the user. For storage of the compressed data, we introduce the BQB file format, which is very robust, flexible, and efficient. In contrast to most archiving formats, it allows fast random access to individual trajectory frames. Our method is implemented in C++ and provided as free software under the GNU LGPL license. It has been included in the TRAVIS program package but is also available as stand-alone tool and as a library ("libbqb") for use in other projects.
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Affiliation(s)
- Martin Brehm
- Institut für Chemie - Theoretische Chemie , Martin-Luther-Universität Halle-Wittenberg , Von-Danckelmann-Platz 4 , 06120 Halle (Saale) , Germany
| | - Martin Thomas
- Institut für Chemie - Theoretische Chemie , Martin-Luther-Universität Halle-Wittenberg , Von-Danckelmann-Platz 4 , 06120 Halle (Saale) , Germany
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23
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Lo Celso F, Yoshida Y, Lombardo R, Jafta C, Gontrani L, Triolo A, Russina O. Mesoscopic structural organization in fluorinated room temperature ionic liquids. CR CHIM 2018. [DOI: 10.1016/j.crci.2018.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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24
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Sheridan QR, Schneider WF, Maginn EJ. Role of Molecular Modeling in the Development of CO2–Reactive Ionic Liquids. Chem Rev 2018; 118:5242-5260. [DOI: 10.1021/acs.chemrev.8b00017] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Quintin R. Sheridan
- Department of Chemical and Biomolecular Engineering, The University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - William F. Schneider
- Department of Chemical and Biomolecular Engineering, The University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Edward J. Maginn
- Department of Chemical and Biomolecular Engineering, The University of Notre Dame, Notre Dame, Indiana 46556, United States
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25
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Koverga V, Kalugin ON, Miannay FA, Smortsova Y, Goloviznina K, Marekha B, Jedlovszky P, Idrissi A. The local structure in the BmimPF6/acetonitrile mixture: the charge distribution effect. Phys Chem Chem Phys 2018; 20:21890-21902. [DOI: 10.1039/c8cp03546f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of the charge distribution on the local structure in the binary mixture of 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6) ionic liquid and acetonitrile is investigated over the entire composition range.
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Affiliation(s)
- Volodymyr Koverga
- University of Lille
- Faculty of Sciences and Technologies
- LASIR (UMR CNRS A8516)
- Villeneuve d’Ascq Cedex
- France
| | - Oleg N. Kalugin
- Department of Inorganic Chemistry
- V.N. Karazin Kharkiv National University
- Kharkiv
- Ukraine
| | - François-Alexandre Miannay
- University of Lille
- Faculty of Sciences and Technologies
- LASIR (UMR CNRS A8516)
- Villeneuve d’Ascq Cedex
- France
| | - Yevheniia Smortsova
- Department of Inorganic Chemistry
- V.N. Karazin Kharkiv National University
- Kharkiv
- Ukraine
| | - Kateryna Goloviznina
- University of Lille
- Faculty of Sciences and Technologies
- LASIR (UMR CNRS A8516)
- Villeneuve d’Ascq Cedex
- France
| | - Bogdan Marekha
- Max Planck Institute for Polymer Research
- Molecular Spectroscopy Department
- 10 Ackermannweg
- 55128 Mainz
- Germany
| | - Pal Jedlovszky
- Department of Chemistry
- Eszterházy Károly University
- H-3300 Eger
- Hungary
| | - Abdenacer Idrissi
- University of Lille
- Faculty of Sciences and Technologies
- LASIR (UMR CNRS A8516)
- Villeneuve d’Ascq Cedex
- France
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26
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Izgorodina EI, Seeger ZL, Scarborough DLA, Tan SYS. Quantum Chemical Methods for the Prediction of Energetic, Physical, and Spectroscopic Properties of Ionic Liquids. Chem Rev 2017; 117:6696-6754. [PMID: 28139908 DOI: 10.1021/acs.chemrev.6b00528] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The accurate prediction of physicochemical properties of condensed systems is a longstanding goal of theoretical (quantum) chemistry. Ionic liquids comprising entirely of ions provide a unique challenge in this respect due to the diverse chemical nature of available ions and the complex interplay of intermolecular interactions among them, thus resulting in the wide variability of physicochemical properties, such as thermodynamic, transport, and spectroscopic properties. It is well understood that intermolecular forces are directly linked to physicochemical properties of condensed systems, and therefore, an understanding of this relationship would greatly aid in the design and synthesis of functionalized materials with tailored properties for an application at hand. This review aims to give an overview of how electronic structure properties obtained from quantum chemical methods such as interaction/binding energy and its fundamental components, dipole moment, polarizability, and orbital energies, can help shed light on the energetic, physical, and spectroscopic properties of semi-Coulomb systems such as ionic liquids. Particular emphasis is given to the prediction of their thermodynamic, transport, spectroscopic, and solubilizing properties.
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Affiliation(s)
- Ekaterina I Izgorodina
- Monash Computational Chemistry Group, School of Chemistry, Monash University , 17 Rainforest Walk, Clayton, Victoria 3800, Australia
| | - Zoe L Seeger
- Monash Computational Chemistry Group, School of Chemistry, Monash University , 17 Rainforest Walk, Clayton, Victoria 3800, Australia
| | - David L A Scarborough
- Monash Computational Chemistry Group, School of Chemistry, Monash University , 17 Rainforest Walk, Clayton, Victoria 3800, Australia
| | - Samuel Y S Tan
- Monash Computational Chemistry Group, School of Chemistry, Monash University , 17 Rainforest Walk, Clayton, Victoria 3800, Australia
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27
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Sheridan QR, Schneider WF, Maginn EJ. Anion Dependent Dynamics and Water Solubility Explained by Hydrogen Bonding Interactions in Mixtures of Water and Aprotic Heterocyclic Anion Ionic Liquids. J Phys Chem B 2016; 120:12679-12686. [PMID: 27973835 DOI: 10.1021/acs.jpcb.6b10631] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular dynamics simulations were used to compare water solubilities and the effects of water on the structure and dynamics of ionic liquids (ILs) composed of phosphonium cations paired with azolide and phenolate anions. The addition of water decreases ordering of the ions compared to the dry ILs with the exception of anion-anion ordering in the phenolate IL. The result is that the dynamics of the azolide ionic liquids increase significantly upon addition of water, whereas the phenolate IL dynamics show little change. The relative water solubilities were compared through calculation of Henry's law constants. Water is much more soluble in the phenolate IL due to strong hydrogen bonding interactions between water and the phenolate oxygen atom. Anions can therefore be selected to control IL-water hydrogen bonding for optimal performance in applications such as CO2 separation.
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Affiliation(s)
- Quintin R Sheridan
- Department of Chemical and Biomolecular Engineering, The University of Notre Dame , Notre Dame, Indiana 46556 United States
| | - William F Schneider
- Department of Chemical and Biomolecular Engineering, The University of Notre Dame , Notre Dame, Indiana 46556 United States
| | - Edward J Maginn
- Department of Chemical and Biomolecular Engineering, The University of Notre Dame , Notre Dame, Indiana 46556 United States
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28
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Firaha DS, Thomas M, Hollóczki O, Korth M, Kirchner B. Can dispersion corrections annihilate the dispersion-driven nano-aggregation of non-polar groups? An ab initio molecular dynamics study of ionic liquid systems. J Chem Phys 2016; 145:204502. [DOI: 10.1063/1.4967861] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Dzmitry S. Firaha
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4+6, D-53115 Bonn, Germany
| | - Martin Thomas
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4+6, D-53115 Bonn, Germany
| | - Oldamur Hollóczki
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4+6, D-53115 Bonn, Germany
| | - Martin Korth
- Institut für Theoretische Chemie, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany
| | - Barbara Kirchner
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4+6, D-53115 Bonn, Germany
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29
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Marekha BA, Koverga VA, Chesneau E, Kalugin ON, Takamuku T, Jedlovszky P, Idrissi A. Local Structure in Terms of Nearest-Neighbor Approach in 1-Butyl-3-methylimidazolium-Based Ionic Liquids: MD Simulations. J Phys Chem B 2016; 120:5029-41. [PMID: 27192134 DOI: 10.1021/acs.jpcb.6b04066] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Description of the local microscopic structure in ionic liquids (ILs) is a prerequisite to obtain a comprehensive understanding of the influence of the nature of ions on the properties of ILs. The local structure is mainly determined by the spatial arrangement of the nearest neighboring ions. Therefore, the main interaction patterns in ILs, such as cation-anion H-bond-like motifs, cation-cation alkyl tail aggregation, and ring stacking, were considered within the framework of the nearest-neighbor approach with respect to each particular interaction site. We employed classical molecular dynamics (MD) simulations to study in detail the spatial, radial, and orientational relative distribution of ions in a set of imidazolium-based ILs, in which the 1-butyl-3-methylimidazolium (C4mim(+)) cation is coupled with the acetate (OAc(-)), chloride (Cl(-)), tetrafluoroborate (BF4(-)), hexafluorophosphate (PF6(-)), trifluoromethanesulfonate (TfO(-)), or bis(trifluoromethanesulfonyl)amide (TFSA(-)) anion. It was established that several structural properties are strongly anion-specific, while some can be treated as universally applicable to ILs, regardless of the nature of the anion. Namely, strongly basic anions, such as OAc(-) and Cl(-), prefer to be located in the imidazolium ring plane next to the C-H(2/4-5) sites. By contrast, the other four bulky and weakly coordinating anions tend to occupy positions above/below the plane. Similarly, the H-bond-like interactions involving the H(2) site are found to be particularly enhanced in comparison with the ones at H(4-5) in the case of asymmetric and/or more basic anions (C4mimOAc, C4mimCl, C4mimTfO, and C4mimTFSA), in accordance with recent spectroscopic and theoretical findings. Other IL-specific details related to the multiple H-bond-like binding and cation stacking issues are also discussed in this paper. The secondary H-bonding of anions with the alkyl hydrogen atoms of cations as well as the cation-cation alkyl chain aggregation turned out to be poorly sensitive to the nature of the anion.
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Affiliation(s)
- Bogdan A Marekha
- LASIR, University of Lille-Science and Technology (UMR CNRS A8516) , Bâtiment C5, Cité Scientifique, 59655, Villeneuve d'Ascq Cedex, France.,Centre d'Etudes et de Recherche sur le Médicament de Normandie (CERMN), UNICAEN, FR CNRS INC3M , Boulevard Becquerel, Caen, 14032 Cedex, France
| | - Volodymyr A Koverga
- LASIR, University of Lille-Science and Technology (UMR CNRS A8516) , Bâtiment C5, Cité Scientifique, 59655, Villeneuve d'Ascq Cedex, France.,Department of Inorganic Chemistry, V. N. Karazin Kharkiv National University , Svobody Square, 4, Kharkiv, 61022, Ukraine
| | - Erwan Chesneau
- LASIR, University of Lille-Science and Technology (UMR CNRS A8516) , Bâtiment C5, Cité Scientifique, 59655, Villeneuve d'Ascq Cedex, France
| | - Oleg N Kalugin
- Department of Inorganic Chemistry, V. N. Karazin Kharkiv National University , Svobody Square, 4, Kharkiv, 61022, Ukraine
| | - Toshiyuki Takamuku
- Department of Chemistry and Applied Chemistry, Graduate School of Science and Engineering, Saga University , Honjo-machi, Saga 840-8502, Japan
| | - Pál Jedlovszky
- Department of Chemistry, Eszterházy Károly University , Leányka Utca 6, H-3300 Eger, Hungary.,MTA-BME Research Group of Technical Analytical Chemistry, Szent Gellért tér 4, H-1111 Budapest, Hungary
| | - Abdenacer Idrissi
- LASIR, University of Lille-Science and Technology (UMR CNRS A8516) , Bâtiment C5, Cité Scientifique, 59655, Villeneuve d'Ascq Cedex, France
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30
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Russina O, De Santis S, Gontrani L. Micro- and mesoscopic structural features of a bio-based choline-amino acid ionic liquid. RSC Adv 2016. [DOI: 10.1039/c6ra02142e] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The structure of bio-based choline–norleucine ionic liquid has been explored by means of combined x-ray diffraction and MD simulations.
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Affiliation(s)
- Olga Russina
- Department of Chemistry
- University of Rome “La Sapienza”
- Rome
- Italy
| | - Serena De Santis
- Department of Chemistry
- University of Rome “La Sapienza”
- Rome
- Italy
| | - Lorenzo Gontrani
- Department of Chemistry
- University of Rome “La Sapienza”
- Rome
- Italy
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Thomas M, Brehm M, Hollóczki O, Kelemen Z, Nyulászi L, Pasinszki T, Kirchner B. Simulating the vibrational spectra of ionic liquid systems: 1-ethyl-3-methylimidazolium acetate and its mixtures. J Chem Phys 2015; 141:024510. [PMID: 25028030 DOI: 10.1063/1.4887082] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The vibrational spectra of the ionic liquid 1-ethyl-3-methylimidazolium acetate and its mixtures with water and carbon dioxide are calculated using ab initio molecular dynamics simulations, and the results are compared to experimental data. The new implementation of a normal coordinate analysis in the trajectory analyzer TRAVIS is used to assign the experimentally observed bands to specific molecular vibrations. The applied computational approaches prove to be particularly suitable for the modeling of bulk phase effects on vibrational spectra, which are highly important for the discussion of the microscopic structure in systems with a strong dynamic network of intermolecular interactions, such as ionic liquids.
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Affiliation(s)
- Martin Thomas
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstraße 4, 53115 Bonn, Germany
| | - Martin Brehm
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Linnéstraße 2, 04103 Leipzig, Germany
| | - Oldamur Hollóczki
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstraße 4, 53115 Bonn, Germany
| | - Zsolt Kelemen
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért tér 4, 1111 Budapest, Hungary
| | - László Nyulászi
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért tér 4, 1111 Budapest, Hungary
| | - Tibor Pasinszki
- Department of Inorganic Chemistry, Institute of Chemistry, Eötvös Loránd University, Pázmány P. sétány 1/A, 1117 Budapest, Hungary
| | - Barbara Kirchner
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstraße 4, 53115 Bonn, Germany
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Thomas M, Brehm M, Kirchner B. Voronoi dipole moments for the simulation of bulk phase vibrational spectra. Phys Chem Chem Phys 2015; 17:3207-13. [DOI: 10.1039/c4cp05272b] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Voronoi tessellation of the electron density in ab initio molecular dynamics simulations is used to calculate vibrational spectra.
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Affiliation(s)
- Martin Thomas
- Mulliken Center for Theoretical Chemistry
- Rheinische Friedrich-Wilhelms-Universität Bonn
- 53115 Bonn
- Germany
| | - Martin Brehm
- Helmholtz-Zentrum für Umweltforschung Leipzig
- 04318 Leipzig
- Germany
| | - Barbara Kirchner
- Mulliken Center for Theoretical Chemistry
- Rheinische Friedrich-Wilhelms-Universität Bonn
- 53115 Bonn
- Germany
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Reid JESJ, Walker AJ, Shimizu S. Residual water in ionic liquids: clustered or dissociated? Phys Chem Chem Phys 2015; 17:14710-8. [DOI: 10.1039/c5cp01854d] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A rigorous statistical thermodynamic theory clarifies how residual water molecules interact in three dialkylimidazolium ionic liquids.
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Affiliation(s)
- Joshua E. S. J. Reid
- York Structural Biology Laboratory
- Department of Chemistry
- University of York
- York YO10 5DD
- UK
| | | | - Seishi Shimizu
- York Structural Biology Laboratory
- Department of Chemistry
- University of York
- York YO10 5DD
- UK
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Kirchner B, Hollóczki O, Canongia Lopes JN, Pádua AAH. Multiresolution calculation of ionic liquids. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2014. [DOI: 10.1002/wcms.1212] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Barbara Kirchner
- Mulliken Center for Theoretical Chemistry; Rheinische Friedrich-Wilhelms-Universität Bonn; Bonn Germany
| | - Oldamur Hollóczki
- Mulliken Center for Theoretical Chemistry; Rheinische Friedrich-Wilhelms-Universität Bonn; Bonn Germany
| | - José Nuno Canongia Lopes
- Centro de Química Estrutural, Instituto Superior Técnico; Universidade de Lisboa; Lisboa Portugal
- Instituto de Tecnologia Química e Biológica; Universidade Nova de Lisboa; Lisboa Portugal
| | - Agílio A. H. Pádua
- Institut de Chimie de Clermont-Ferrand; Université Blaise Pascal and CNRS; Clermont-Ferrand France
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Acevedo O. Simulating chemical reactions in ionic liquids using QM/MM methodology. J Phys Chem A 2014; 118:11653-66. [PMID: 25329366 DOI: 10.1021/jp507967z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The use of ionic liquids as a reaction medium for chemical reactions has dramatically increased in recent years due in large part to the numerous reported advances in catalysis and organic synthesis. In some extreme cases, ionic liquids have been shown to induce mechanistic changes relative to conventional solvents. Despite the large interest in the solvents, a clear understanding of the molecular factors behind their chemical impact is largely unknown. This feature article reviews our efforts developing and applying mixed quantum and molecular mechanical (QM/MM) methodology to elucidate the microscopic details of how these solvents operate to enhance rates and alter mechanisms for industrially and academically important reactions, e.g., Diels-Alder, Kemp eliminations, nucleophilic aromatic substitutions, and β-eliminations. Explicit solvent representation provided the medium dependence of the activation barriers and atomic-level characterization of the solute-solvent interactions responsible for the experimentally observed "ionic liquid effects". Technical advances are also discussed, including a linear-scaling pairwise electrostatic interaction alternative to Ewald sums, an efficient polynomial fitting method for modeling proton transfers, and the development of a custom ionic liquid OPLS-AA force field.
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Affiliation(s)
- Orlando Acevedo
- Department of Chemistry and Biochemistry, Auburn University , Auburn, Alabama 36849, United States
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Stark A. Shaping micro- and macroscopic properties of ionic liquid–solute systems: Multi-functional task-specific agents. J Mol Liq 2014. [DOI: 10.1016/j.molliq.2013.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Fong-Padrón C, Cabaleiro-Lago EM, Rodríguez-Otero J. Water interaction with ion pairs from ionic liquids. Computational study and performance assessment of several common functionals. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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39
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Thomas M, Brehm M, Hollóczki O, Kirchner B. How Can a Carbene be Active in an Ionic Liquid? Chemistry 2013; 20:1622-9. [DOI: 10.1002/chem.201303329] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Revised: 11/14/2013] [Indexed: 11/10/2022]
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40
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Clough MT, Geyer K, Hunt PA, Mertes J, Welton T. Thermal decomposition of carboxylate ionic liquids: trends and mechanisms. Phys Chem Chem Phys 2013; 15:20480-95. [DOI: 10.1039/c3cp53648c] [Citation(s) in RCA: 188] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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41
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Stark A, Brehm M, Brüssel M, Lehmann SBC, Pensado AS, Schöppke M, Kirchner B. A theoretical and experimental chemist's joint view on hydrogen bonding in ionic liquids and their binary mixtures. Top Curr Chem (Cham) 2013; 351:149-87. [PMID: 24682761 DOI: 10.1007/128_2013_485] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A combined experimental and theoretical approach including quantum chemistry tools and computational simulation techniques can provide a holistic description of the nature of the interactions present in ionic liquid media. The nature of hydrogen bonding in ionic liquids is an especially intriguing aspect, and it is affected by all types of interactions occurring in this media. Overall, these interactions represent a delicate balance of forces that influence the structure and dynamics, and hence the properties of ionic liquids. An understanding of the fundamental principles can be achieved only by a combination of computations and experimental work. In this contribution we show recent results shedding light on the nature of hydrogen bonding, for certain cases the formation of a three-dimensional network of hydrogen bonding, and its dynamics by comparing 1-ethyl-3-methylimidazolium based acetate, chloride and thiocyanate ionic liquids.A particularly interesting case to study hydrogen bonding and other interactions is the investigation of binary mixtures of ionic liquids of the type [cation1][anion1]/[cation1][anion2]. In these mixtures, competing interactions are to be expected. We present both a thorough property meta-analysis of the literature and new data covering a wide range of anions, i.e., mixtures of 1-ethyl-3-methylimidazolium acetate with either trifluoroacetate, tetrafluoroborate, methanesulfonate, or bis(trifluoromethanesulfonyl)imide. In most cases, ideal mixing behavior is found, a surprising result considering the multitude of interactions present. However, ideal mixing behavior allows for the prediction of properties such as density, refractive index, surface tension, and, in most cases, viscosity as function of molar composition. Furthermore, we show that the prediction of properties such as the density of binary ionic liquid mixtures is possible by making use of group contribution methods which were originally developed for less complex non-ionic molecules. Notwithstanding this ideal mixing behavior, several exciting applications are discussed where preferential solvation via hydrogen bonding gives rise to non-additive effects leading to performance improvements. The assessment of the excess properties and (1)H NMR spectroscopic studies provide information on these structural changes and preferential interactions occurring in binary mixtures of ionic liquid, that clearly support the conclusions drawn from the computational studies.
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Affiliation(s)
- Annegret Stark
- Institute for Chemical Technology, Universität Leipzig, Linnéstr. 3-4, 04103, Leipzig, Germany,
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