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Khudozhitkov AE, Stepanov AG, Kolokolov DI, Ludwig R. Ion Mobility in Hydroxy-Functionalized Ionic Liquids Depends on Cationic Clustering: Tracking the Alkyl Chain Length Behavior with Deuteron NMR Relaxation. J Phys Chem B 2023; 127:9336-9345. [PMID: 37857325 DOI: 10.1021/acs.jpcb.3c05330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Observing and quantifying the like-charge attraction in liquids and solutions is still challenging. However, we showed that elusive cation-cation hydrogen bonding may govern the structure and interaction in hydroxyl-functionalized ionic liquids. Therefore, cationic cluster formation depends on the shape, charge distribution, and functionality of the ions. We demonstrated by means of solid-state 2H NMR spectroscopy that cationic clusters change the structure and dynamics of ionic liquids. With increasing alkyl chain length, we observed two deuteron quadrupole coupling constants for the OD groups, differing by about 30 kHz. The lower value was assigned to the cation-cation interaction, indicating that the average (c-c) hydrogen bonds are stronger than the (c-a) hydrogen bonds between the cation and the anion despite the repulsive and attractive Coulomb interaction in the first and latter cases. Ion mobility could be studied by 2H NMR spectroscopy, although the deuterons in the hydrogen-bonded clusters underwent fast exchange. Our results also showed that simple relaxation models are not applicable anymore and that anisotropic motion must be considered.
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Affiliation(s)
- Alexander E Khudozhitkov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
| | - Alexander G Stepanov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia
| | - Daniil I Kolokolov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
| | - Ralf Ludwig
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Albert-Einstein-Str. 27, 18059 Rostock, Germany
- Department LL&M, University of Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany
- Leibniz-Institut für Katalyse an der Universität Rostock e.V., Albert-Einstein-Str. 29a, 18059 Rostock, Germany
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2
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Khudozhitkov AE, Paschek D, Stepanov AG, Kolokolov DI, Ludwig R. How Like-Charge Attraction Influences the Mobility of Cations in Hydroxyl-Functionalized Ionic Liquids. J Phys Chem Lett 2023; 14:4019-4025. [PMID: 37093004 DOI: 10.1021/acs.jpclett.3c00463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Attractive interactions between ions of like charge remain an elusive concept. Observing and quantifying this type of interaction in liquids and solutions is still a major challenge. Recently, we have shown that cation-cation interactions are present in hydroxyl-functionalized ionic liquids and that they can be controlled by the shape, charge distribution and functionality of the ions. In the present study, we demonstrate that cationic cluster formation does not only change the local structures of the ionic liquids but also influences the dynamics of the cations in a characteristic way. We show that solid-state 2H NMR spectroscopy is well suited for the study of molecular motion, even if the hydrogen bonded species of interest are indistinguishable due to fast deuteron exchange. We also provide valuable information about the applicability of well-accepted relaxation models.
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Affiliation(s)
- Alexander E Khudozhitkov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
| | - Dietmar Paschek
- Institut für Chemie, Abteilung für Physikalische Chemie, Universität Rostock, Albert-Einstein-Strasse 27, 18059 Rostock, Germany
| | - Alexander G Stepanov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia
| | - Daniil I Kolokolov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
| | - Ralf Ludwig
- Institut für Chemie, Abteilung für Physikalische Chemie, Universität Rostock, Albert-Einstein-Strasse 27, 18059 Rostock, Germany
- Department LL&M, University of Rostock, Albert-Einstein-Strasse 25, 18059 Rostock, Germany
- Leibniz-Institut für Katalyse an der Universität Rostock e.V., Albert-Einstein-Strasse 29a, 18059 Rostock, Germany
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3
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Khudozhitkov AE, Stange P, Paschek D, Stepanov AG, Kolokolov DI, Ludwig R. The Influence of Deuterium Isotope Effects on Structural Rearrangements, Ensemble Equilibria, and Hydrogen Bonding in Protic Ionic Liquids. Chemphyschem 2022; 23:e202200557. [PMID: 35944124 PMCID: PMC10087857 DOI: 10.1002/cphc.202200557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Indexed: 01/05/2023]
Abstract
We report strong isotope effects for the protic ionic liquid triethylammonium methanesulfonate [TEA][OMs] by means of deuterium solid-state NMR spectroscopy covering broad temperature ranges from 65 K to 313 K. Both isotopically labelled PILs differ in non-deuterated and fully deuterated ethyl groups of the triethyl ammonium cations. The N-D bond of both cations is used as sensitive probe for hydrogen bonding and structural ordering. The 2 H NMR line shape analysis provides the deuteron quadrupole coupling constants and the characteristics of a broad heterogeneous phase with simultaneously present static and mobile states indicating plastic crystal behavior. The temperatures where both states are equally populated differ by about 80 K for the two PILs, showing that deuteration of the ethyl groups in the trialkylammonium cations tremendously shifts the equilibrium towards the static state. In addition, it leads to a significant less cooperative transition, associated with a significantly reduced standard molar transition entropy.
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Affiliation(s)
- Alexander E Khudozhitkov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk, 630090, Russia.,Novosibirsk State University, Pirogova Street 2, Novosibirsk, 630090, Russia
| | - Peter Stange
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Albert-Einstein-Straße 27, 18059, Rostock, Germany
| | - Dietmar Paschek
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Albert-Einstein-Straße 27, 18059, Rostock, Germany
| | - Alexander G Stepanov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk, 630090, Russia
| | - Daniil I Kolokolov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk, 630090, Russia.,Novosibirsk State University, Pirogova Street 2, Novosibirsk, 630090, Russia
| | - Ralf Ludwig
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Albert-Einstein-Straße 27, 18059, Rostock, Germany.,Leibniz-Institut für Katalyse an der Universität Rostock e.V., Albert-Einstein-Str. 29a, 18059, Rostock, Germany
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4
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Structural Anomaly in Glasses: Molecular Dynamics Study of Organic Radical in Dibutylphthalate at Different Temperatures. Int J Mol Sci 2022; 23:ijms232314859. [PMID: 36499187 PMCID: PMC9735606 DOI: 10.3390/ijms232314859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/18/2022] [Accepted: 11/23/2022] [Indexed: 12/03/2022] Open
Abstract
Understanding the heterogeneous nano/microscopic structures of various organic glasses is fundamental and necessary for many applications. Recently, unusual structural phenomena have been observed experimentally in various organic glasses near their glass transition temperatures (Tg), including dibutyl phthalate (DBP). In particular, the librational motion of radical probe in the glass is progressively suppressed upon temperature increase. In this work, we report in-depth molecular dynamics studies of structural anomalies in DBP glass, that revealed insights into the general mechanism of these phenomena. In particular, we have evidenced that the two types of solvation within alkyl chains coexist, allowing only small-angle wobbling of the solute molecule (TEMPO radical), and another favouring large-angle rotations. The former solvation assumes constrained location of the solute near carboxyl groups of DBP, while the latter is coupled to the concerted movement of butyl chains. Remarkably, excellent qualitative and quantitative agreement with previous experimental results were obtained. As such, we are certain that the above-mentioned dynamic phenomena explain the intriguing structural anomalies observed in DBP and some other glasses in the vicinity of Tg.
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Bakulina OD, Ivanov MY, Alimov DV, Prikhod’ko SA, Adonin NY, Fedin MV. Active Pharmaceutical Ingredient-Ionic Liquids (API-ILs): Nanostructure of the Glassy State Studied by Electron Paramagnetic Resonance Spectroscopy. Molecules 2022; 27:molecules27165117. [PMID: 36014356 PMCID: PMC9415235 DOI: 10.3390/molecules27165117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 07/22/2022] [Accepted: 08/02/2022] [Indexed: 12/02/2022] Open
Abstract
Active Pharmaceutical Ingredient-Ionic Liquids (API-ILs) draw increasing interest as a particular class of ILs that possess unusual physicochemical properties along with simultaneous potentials for pharmaceutical applications. Although nanostructuring phenomena were actively investigated in common ILs, their studies in API-ILs are scarce so far. In this work, using the complex methodology of Electron Paramagnetic Resonance (EPR) and dissolved spin probes, we investigate nanostructuring phenomena in a series of API-ILs: [Cnmim][Ibu], [Cnmim][Gly], and [Cnmim][Sal] with n = 2, 4, and 6, respectively. We reveal similar trends for API-ILs and common ILs, as well as peculiarities inherent to the studied API-ILs. Unusual behavior observed for [Cnmim][Ibu] has been assigned to the presence of a non-polar fragment in the [Ibu]− anion, which leads to the formation of more complex nanostructures around the radical compared to common ILs. Understanding general trends in the formation of such self-organized molecular structures is of fundamental interest and importance for applying API-ILs.
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Affiliation(s)
- Olga D. Bakulina
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia
- Physics Department, Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
| | - Mikhail Yu. Ivanov
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia
- Physics Department, Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
- Correspondence: (M.Y.I.); (M.V.F.)
| | - Dmitriy V. Alimov
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia
- Physics Department, Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
| | - Sergey A. Prikhod’ko
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia
| | - Nicolay Yu. Adonin
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia
| | - Matvey V. Fedin
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia
- Physics Department, Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
- Correspondence: (M.Y.I.); (M.V.F.)
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6
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Khudozhitkov AE, Donoshita M, Stepanov AG, Philippi F, Rauber D, Hempelmann R, Kitagawa H, Kolokolov DI, Ludwig R. High‐Temperature Quantum Tunneling and Hydrogen Bonding Rearrangements Characterize the Solid‐Solid Phase Transitions in a Phosphonium‐Based Protic Ionic Liquid. Chemistry 2022; 28:e202200257. [PMID: 35187737 PMCID: PMC9311734 DOI: 10.1002/chem.202200257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Alexander E. Khudozhitkov
- Boreskov Institute of Catalysis Siberian Branch of Russian Academy of Sciences Prospekt Akademika Lavrentieva 5 Novosibirsk 630090 Russia
- Novosibirsk State University Pirogova Street 2 Novosibirsk 630090 Russia
| | - Masaki Donoshita
- Division of Chemistry Graduate School of Science Kyoto University Kitashirakawa-Oiwakecho, Sakyo-ku Kyoto 606-8502 Japan
| | - Alexander G. Stepanov
- Boreskov Institute of Catalysis Siberian Branch of Russian Academy of Sciences Prospekt Akademika Lavrentieva 5 Novosibirsk 630090 Russia
- Novosibirsk State University Pirogova Street 2 Novosibirsk 630090 Russia
| | - Frederik Philippi
- Physikalische Chemie Universität des Saarlandes Campus B2.2 66123 Saarbrücken Germany
| | - Daniel Rauber
- Physikalische Chemie Universität des Saarlandes Campus B2.2 66123 Saarbrücken Germany
| | - Rolf Hempelmann
- Physikalische Chemie Universität des Saarlandes Campus B2.2 66123 Saarbrücken Germany
| | - Hiroshi Kitagawa
- Division of Chemistry Graduate School of Science Kyoto University Kitashirakawa-Oiwakecho, Sakyo-ku Kyoto 606-8502 Japan
| | - Daniil I. Kolokolov
- Boreskov Institute of Catalysis Siberian Branch of Russian Academy of Sciences Prospekt Akademika Lavrentieva 5 Novosibirsk 630090 Russia
- Novosibirsk State University Pirogova Street 2 Novosibirsk 630090 Russia
| | - Ralf Ludwig
- Department LL&M University of Rostock Albert-Einstein-Str. 25 18059 Rostock Germany
- Institut für Chemie Abteilung für Physikalische Chemie Universität Rostock Dr.-Lorenz-Weg 2 18059 Rostock Germany
- Leibniz-Institut für Katalyse Universität Rostock e.V. Albert-Einstein-Str. 29a 18059 Rostock Germany
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7
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Damodaran K. Recent advances in NMR spectroscopy of ionic liquids. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 129:1-27. [PMID: 35292132 DOI: 10.1016/j.pnmrs.2021.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 12/17/2021] [Accepted: 12/28/2021] [Indexed: 06/14/2023]
Abstract
This review presents recent developments in the application of NMR spectroscopic techniques in the study of ionic liquids. NMR has been the primary tool not only for the structural characterization of ionic liquids, but also for the study of dynamics. The presence of a host of NMR active nuclei in ionic liquids permits widespread use of multinuclear NMR experiments. Chemical shifts and multinuclear coupling constants are used routinely for the structure elucidation of ionic liquids and of products formed by their covalent interactions with other materials. Also, the availability of a multitude of NMR techniques has facilitated the study of dynamical processes in them. These include the use of NOESY to study inter-ionic interactions, pulsed-field gradient techniques for probing transport properties, and relaxation measurements to elucidate rotational dynamics. This review will focus on the application of each of these techniques to investigate ionic liquids.
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Affiliation(s)
- Krishnan Damodaran
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States.
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8
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Khudozhitkov AE, Stange P, Stepanov AG, Kolokolov DI, Ludwig R. Structure, hydrogen bond dynamics and phase transition in a model ionic liquid electrolyte. Phys Chem Chem Phys 2022; 24:6064-6071. [PMID: 35212342 DOI: 10.1039/d2cp00452f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We show that solid-state NMR spectroscopy is a suitable method for characterizing the structure, hydrogen bond dynamics and phase transition behavior in protic ionic liquids (PILs). Deuteron line shape and spin relaxation time analysis provide a description of the structural and dynamical heterogeneity in the solid state of the model PIL triethyl ammonium bis(trifluoromethanesulfonyl)amide [TEA][NTf2]. Therein, we observed two deuteron quadrupole coupling constant for the ND bond of the TEA cation, indicating differently strong hydrogen bonds to the nitrogen and oxygen atoms of the NTf2 anion, as we could confirm by DFT calculations. The transition processes in the dynamically heterogeneous phase are characterized by two standard molar enthalpies and thus different stages of melting. We provide geometry, rates and energetics of the cation in the solid and liquid states of the PIL. Comparison with PILs having stronger interacting anions shows higher enthalpy change between the solid and liquid states, lower activation barriers of tumbling motion and higher amplitude of librational motion for the TEA cation in the presence of the weakly interacting anion NTf2. We provide reasonable relations between microscopic and macroscopic properties, as is relevant for any kind of application.
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Affiliation(s)
- Alexander E Khudozhitkov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia. .,Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
| | - Peter Stange
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr-Lorenz-Weg 2, 18059 Rostock, Germany
| | - Alexander G Stepanov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia.
| | - Daniil I Kolokolov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia. .,Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
| | - Ralf Ludwig
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr-Lorenz-Weg 2, 18059 Rostock, Germany.,Leibniz-Institut für Katalyse an der Universität Rostock e.V, Albert-Einstein-Str. 29a, 18059 Rostock, Germany.
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9
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EPR study of nanostructuring in protic ionic liquids [PriNH3]NO3 and [BuNH3]NO3. Russ Chem Bull 2022. [DOI: 10.1007/s11172-021-3353-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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10
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Zhu H, O'Dell LA. Nuclear magnetic resonance characterisation of ionic liquids and organic ionic plastic crystals: common approaches and recent advances. Chem Commun (Camb) 2021; 57:5609-5625. [PMID: 34048516 DOI: 10.1039/d1cc02151f] [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
Ionic liquids, and their solid-state equivalents organic ionic plastic crystals, show many useful and tailorable properties that make them interesting for a wide range of applications including as electrolytes for energy storage devices. Nuclear magnetic resonance spectroscopy and related techniques offer a powerful and versatile toolkit for the characterisation of structure, interactions and dynamics in these materials. This article summarises both commonly used methods and some recent advances in this area, including solution- and solid-state methods, dynamic nuclear polarisation, imaging, diffusion and relaxation measurements, and example applications of some less commonly studied nuclei.
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Affiliation(s)
- Haijin Zhu
- Institute for Frontier Materials, Deakin University, Geelong Waurn Ponds Campus, Victoria 3220, Australia.
| | - Luke A O'Dell
- Institute for Frontier Materials, Deakin University, Geelong Waurn Ponds Campus, Victoria 3220, Australia.
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11
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Overbeck V, Appelhagen A, Rößler R, Niemann T, Ludwig R. Rotational correlation times, diffusion coefficients and quadrupolar peaks of the protic ionic liquid ethylammonium nitrate by means of 1H fast field cycling NMR relaxometry. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114983] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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12
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Overbeck V, Schröder H, Bonsa AM, Neymeyr K, Ludwig R. Insights into the translational and rotational dynamics of cations and anions in protic ionic liquids by means of NMR fast-field-cycling relaxometry. Phys Chem Chem Phys 2021; 23:2663-2675. [PMID: 33480888 DOI: 10.1039/d0cp05440b] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Understanding the translational and rotational dynamics of cations and anions in hydrogen bonded protic ionic liquids (PIls) is still a challenge. In this study, we determine self-diffusion coefficients and rotational correlation times of both ions in triethylammonium based PILs by means of NMR Fast-Field-Cycling (FFC) relaxometry. Global fits of 1H and 19F nuclear magnetic relaxation dispersion (NMRD) curves allowed proper separation into intra and inter molecular relaxation rates for both NMR sensitive nuclei and thus a reliable description of translational and rotational motion for both ions individually. The diffusion coefficients of the cations are in the order of 6 × 10-11 m2 s-1 at room temperature and about 50 per cent larger than those of the anions. The diffusion coefficients of cations and anions in both PILs were compared with those we derived from applying an universal dispersion power law and those known from pulsed field gradient (PFG) NMR studies. Considering the Nernst-Einstein equation, molar conductivities were calculated from cationic and anionic diffusion coefficients and related to directly measured molar conductivities, allowing the determination of the degree of dissociation. The rotational correlation times τR ranging from 50 ps up to 2 ns as a function of temperature were compared with those obtained from high-field NMR quadrupolar relaxation time measurements addressing explicitly the rotation of the NH vector and giving insights into the acidic proton mobility. The Stokes-Einstein and Stokes-Einstein-Debye relations were applied to relate the diffusion coefficients and rotational correlation times to the macroscopic bulk viscosity. The results were also discussed with respect to the archetypical PIL ethylammonium nitrate.
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Affiliation(s)
- Viviane Overbeck
- Department LL&M, University of Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany. and Physical and Theoretical Chemistry, Department of Chemistry, University of Rostock, Dr-Lorenz-Weg 2, 18059 Rostock, Germany
| | - Henning Schröder
- Department of Mathematics, University of Rostock, Ulmenstr. 69, 18057 Rostock, Germany
| | - Anne-Marie Bonsa
- Department LL&M, University of Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany. and Physical and Theoretical Chemistry, Department of Chemistry, University of Rostock, Dr-Lorenz-Weg 2, 18059 Rostock, Germany
| | - Klaus Neymeyr
- Department of Mathematics, University of Rostock, Ulmenstr. 69, 18057 Rostock, Germany
| | - Ralf Ludwig
- Department LL&M, University of Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany. and Physical and Theoretical Chemistry, Department of Chemistry, University of Rostock, Dr-Lorenz-Weg 2, 18059 Rostock, Germany and Leibniz Institute for Catalysis e.V., Albert-Einstein-Str. 29a, 18059 Rostock, Germany
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13
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Ivanov MY, Poryvaev AS, Polyukhov DM, Prikhod'ko SA, Adonin NY, Fedin MV. Nanoconfinement effects on structural anomalies in imidazolium ionic liquids. NANOSCALE 2020; 12:23480-23487. [PMID: 33174581 DOI: 10.1039/d0nr06961b] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Imidazolium Ionic Liquids (ILs) have been found to exhibit unusual nanostructuring behavior below their glass transition temperatures (Tg), which is ascribed to rearrangements in nonpolar domains formed by segregated alkyl chains. However, the dimensions required for such highly cooperative bulk phenomena are still unknown. In this work, we for the first time, investigate the effect of nanoconfinement on structural anomalies in imidazolium ILs. For this purpose, a series of ILs were embedded into the cavities of metal-organic framework (MOF) ZIF-8 and investigated using spin probes and Electron Paramagnetic Resonance (EPR) spectroscopy. The unusual nanostructuring near Tg, previously known for bulk ILs, was also observed for such nanoconfined ILs, and the amplitude of the anomaly was found to be dependent on the structure of the IL, thus showing the effects of molecular packing inside the MOF cavity. The first observation of structural anomalies in nanoconfined ILs opens perspectives for designing smart materials exhibiting these phenomena, and engaging MOFs as platforms creates the basis for potential applications of such functionalities.
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Affiliation(s)
- Mikhail Yu Ivanov
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia.
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14
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Bakulina OD, Ivanov MY, Prikhod'ko SA, Pylaeva S, Zaytseva IV, Surovtsev NV, Adonin NY, Fedin MV. Nanocage formation and structural anomalies in imidazolium ionic liquid glasses governed by alkyl chains of cations. NANOSCALE 2020; 12:19982-19991. [PMID: 32996529 DOI: 10.1039/d0nr06065h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Intriguing nanostructuring anomalies have been recently observed in imidazolium ionic liquids (ILs) near their glass transition points, where local density around a nanocaged solute progressively grows up with temperature. Herewith, we for the first time demonstrate experimentally and theoretically, that these anomalies are governed by alkyl chains of cations and crucially depend on their length. Electron Paramagnetic Resonance (EPR) spectroscopy on a series of ILs [Cnmim]BF4 (n = 0-12) shows that only the chains with n = 3-10 favor anomaly. Moreover, remarkable even vs. odd n peculiarities were systematically observed. Finally, similar anomaly was for the first time observed for a non-IL glass of dibutyl phthalate, which structurally mimics cations of imidazolium ILs. Therefore, such anomalous density behavior in a glassy state nanocage goes far beyond ILs and proves to be a more general phenomenon, which can be structurally tuned and rationally adjusted for various potential applications in nanoscale materials.
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Affiliation(s)
- Olga D Bakulina
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia.
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15
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Steinrücken E, Becher M, Vogel M. On the molecular mechanisms of α and β relaxations in ionic liquids. J Chem Phys 2020; 153:104507. [DOI: 10.1063/5.0019271] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Elisa Steinrücken
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Manuel Becher
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Michael Vogel
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany
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Khudozhitkov AE, Overbeck V, Stange P, Strate A, Zaitsau D, Appelhagen A, Michalik D, Stepanov AG, Kolokolov DI, Paschek D, Ludwig R. Simultaneous determination of deuteron quadrupole coupling constants and rotational correlation times: the model case of hydrogen bonded ionic liquids. Phys Chem Chem Phys 2019; 21:25597-25605. [DOI: 10.1039/c9cp04983e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We show that deuteron quadrupole coupling constants, and reorientational correlation times of molecular bonds N–D that are involved in hydrogen bonding, can be determined from NMR T1 relaxation time experiments simultaneously by assuming anisotropic motion.
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Wiedemann C, Hempel G, Bordusa F. Reorientation dynamics and ion diffusivity of neat dimethylimidazolium dimethylphosphate probed by NMR spectroscopy. RSC Adv 2019; 9:35735-35750. [PMID: 35528082 PMCID: PMC9074696 DOI: 10.1039/c9ra07731f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 10/28/2019] [Indexed: 11/21/2022] Open
Abstract
NMR spectroscopy at two magnetic field strengths was employed to investigate the dynamics of dimethylimidazolium dimethylphosphate ([C1C1IM][(CH3)2PO4]). [C1C1IM][(CH3)2PO4] is a low-melting, halogen-free ionic liquid comprising of only methyl groups. 13C spin–lattice relaxation rates as well as self-diffusion coefficients were measured for [C1C1IM][(CH3)2PO4] as a function of temperature. The rotational correlation times, τc, for the cation and the anion were obtained from the 13C spin–lattice relaxation rates. Although from a theoretical point of view cations and anions are similar in size, they show different reorientation mobilities and diffusivities. The self-diffusion coefficients and the rotational correlation times were related to the radii of the diffusing spheres. The analysis reveals that the radii of the cation and the anion, respectively, are different from each other but constant at temperatures ranging from 293 to 353 K. The experimental results are rationalised by a discrete and individual cation and anion diffusion. The [(CH3)2PO4]− anion reorients faster compared to the cation but diffuses significantly slower indicating the formation of anionic aggregates. Relaxation data were acquired with standard liquid and magic-angle-spinning NMR probes to estimate residual dipolar interactions, chemical shift anisotropy or differences in magnetic susceptibility within the sample. Liquid and HR-MAS NMR spectroscopy at two magnetic field strengths was employed to investigate the dynamics of ([C1C1IM][(CH3)2PO4]).![]()
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Affiliation(s)
- Christoph Wiedemann
- Institute of Biochemistry and Biotechnology
- Charles Tanford Protein Center
- Martin Luther University Halle-Wittenberg
- D-06120 Halle (Saale)
- Germany
| | - Günter Hempel
- Institute of Physics
- Martin Luther University Halle-Wittenberg
- D-06120 Halle (Saale)
- Germany
| | - Frank Bordusa
- Institute of Biochemistry and Biotechnology
- Charles Tanford Protein Center
- Martin Luther University Halle-Wittenberg
- D-06120 Halle (Saale)
- Germany
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Linking Structure to Dynamics in Protic Ionic Liquids: A Neutron Scattering Study of Correlated and Single-Particle Motions. Sci Rep 2018; 8:16400. [PMID: 30401950 PMCID: PMC6219547 DOI: 10.1038/s41598-018-34481-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/18/2018] [Indexed: 11/22/2022] Open
Abstract
Coupling between dynamical heterogeneity of ionic liquids and their structural periodicity on different length-scales can be directly probed by quasielastic neutron scattering with polarization analysis. The technique provides the tools to investigate single-particle and cooperative ion motions separately and, thus, dynamics of ion associations affecting the net charge transport can be experimentally explored. The focus of this study is the structure-dynamic relationship in the protic ionic liquid, triethylammonium triflate, characterized by strong hydrogen bonds between cations and anions. The site-selective deuterium/hydrogen-isotope substitution was applied to modulate the relative contributions of different atom groups to the total coherent and incoherent scattering signal. This approach in combination with molecular dynamics simulations allowed us to obtain a sophisticated description of cation self-diffusion and confined ion pair dynamics from the incoherent spectral component by using the acidic proton as a tagged particle. The coherent contribution of the neutron spectra demonstrated substantial ion association leading to collective ion migration that preserves charge alteration on picosecond time scale, as well as correlation of the localized dynamics occurring between adjacent ions.
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Ivanov MY, Fedin MV. Nanoscale heterogeneities in ionic liquids: insights from EPR of spin probes. MENDELEEV COMMUNICATIONS 2018. [DOI: 10.1016/j.mencom.2018.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Zhou S, Zhu G, Kang X, Li Q, Sha M, Cui Z, Xu X. Molecular dynamics simulation of the ionic liquid N-octylpyridinium tetrafluoroborate and acetonitrile: Thermodynamic and structural properties. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2018.04.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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