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Hunger L, Al Sheakh L, Fritsch S, Villinger A, Ludwig R, Harville P, Moss O, Lachowicz A, Johnson MA. Spectroscopic Evidence for Doubly Hydrogen-Bonded Cationic Dimers in the Solid, Liquid, and Gaseous Phases of Carboxyl-Functionalized Ionic Liquids. J Phys Chem B 2024; 128:5463-5471. [PMID: 38776534 DOI: 10.1021/acs.jpcb.4c02094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Intermolecular interactions determine whether matter sticks together, gases condense into liquids, or liquids freeze into solids. The most prominent example is hydrogen bonding in water, responsible for the anomalous properties in the liquid phase and polymorphism in ice. The physical properties are also exceptional for ionic liquids (ILs), wherein a delicate balance of Coulomb interactions, hydrogen bonds, and dispersion interactions results in a broad liquid range and the vaporization of ILs as ion pairs. In this study, we show that strong, local, and directional hydrogen bonds govern the structures and arrangements in the solid, liquid, and gaseous phases of carboxyl-functionalized ILs. For that purpose, we explored the H-bonded motifs by X-ray diffraction and attenuated total reflection (ATR) infrared (IR) spectroscopy in the solid state, by ATR and transmission IR spectroscopy in the liquid phase, and by cryogenic ion vibrational predissociation spectroscopy (CIVPS) in the gaseous phase at low temperature. The analysis of the CO stretching bands reveals doubly hydrogen-bonded cationic dimers (c═c), resembling the archetype H-bond motif known for carboxylic acids. The like-charge doubly hydrogen-bonded ion pairs are present in the crystal structure of the IL, survive phase transition into the liquid state, and are still present in the gaseous phase even in (2,1) complexes wherein one counterion is removed and repulsive Coulomb interaction increased. The interpretation of the vibrational spectra is supported by quantum chemical methods. These observations have implications for the fundamental nature of the hydrogen bond between ions of like charge.
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Affiliation(s)
- Lasse Hunger
- Department of Chemistry, University of Rostock, 18059 Rostock, Germany
- Department Life, Light & Matter, University of Rostock, 18051 Rostock, Germany
| | - Loai Al Sheakh
- Department of Chemistry, University of Rostock, 18059 Rostock, Germany
- Department Life, Light & Matter, University of Rostock, 18051 Rostock, Germany
| | - Sebastian Fritsch
- Department of Chemistry, University of Rostock, 18059 Rostock, Germany
- Department Life, Light & Matter, University of Rostock, 18051 Rostock, Germany
| | | | - Ralf Ludwig
- Department of Chemistry, University of Rostock, 18059 Rostock, Germany
- Department Life, Light & Matter, University of Rostock, 18051 Rostock, Germany
- Leibniz-Institut für Katalyse e.V., Albert-Einstein-Str. 29a, 18059 Rostock, Germany
| | - Payten Harville
- Sterling Chemistry Laboratory, Yale University, New Haven, Connecticut 06520, United States
| | - Olivia Moss
- Sterling Chemistry Laboratory, Yale University, New Haven, Connecticut 06520, United States
| | - Anton Lachowicz
- Sterling Chemistry Laboratory, Yale University, New Haven, Connecticut 06520, United States
| | - Mark A Johnson
- Sterling Chemistry Laboratory, Yale University, New Haven, Connecticut 06520, United States
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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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Stange P, Verevkin SP, Ludwig R. Combined Spectroscopic, Thermodynamic, and Theoretical Approach for Detecting and Quantifying Hydrogen Bonding and Dispersion Interaction in Ionic Liquids. Acc Chem Res 2023; 56:3441-3450. [PMID: 37956209 DOI: 10.1021/acs.accounts.3c00530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
ConspectusIonic liquids (ILs) are attracting increasing interest in science and engineering due to their unique properties that can be tailored for specific applications. Clearly, a better understanding of their behavior on the microscopic scale will help to elucidate macroscopic fluid phenomena and thereby promote potential applications. The advantageous properties of these innovative fluids arise from the delicate balance of Coulomb interactions, hydrogen bonding, and dispersion forces. The development of these properties requires a fundamental understanding of the strength, location, and direction of the different types of interactions and their contribution to the overall phase behavior. Contrary to expectations, hydrogen bonding and dispersion interactions have a significant influence on the structure, dynamics, and phase behavior of ILs.The synergy between experimental and theoretical methods has now advanced to a stage where hydrogen bonds and dispersion effects as well as the competition between the two can be studied in detail. In this account, we demonstrate that a suitable combination of spectroscopic, thermodynamic, and theoretical methods enables the detection, dissection, and quantification of noncovalent interactions, even in complex systems such as ionic liquids. This approach encompasses far-infrared vibrational spectroscopy (FIR), various thermodynamic methods for determining enthalpies of vaporization, and quantum chemical techniques that allow us to switch dispersion contributions on or off when calculating the energies and spectroscopic properties of clusters.We briefly discuss these experimental and theoretical methods, before providing various examples illustrating how the mélange of Coulomb interaction, hydrogen bonds, and dispersion forces can be analyzed, and their individual contributions quantified. First, we demonstrated that both hydrogen bonding and dispersion interactions are manifested in the FIR spectra and can be quantified by observed shifts of characteristic spectral signatures. Through the selection of suitable protic ionic liquids (PILs) featuring anions with varying interaction strengths and alkyl chain lengths, we were able to demonstrate that dispersion interactions can compete with hydrogen bonding. The resultant transition enthalpy serves as a measure of the dispersion interaction. Contrary to expectations, PILs possess lower enthalpies of vaporization compared with aprotic ILs (AILs). The reason for this is simple: In protic ILs, ion pairs carry both the hydrogen bond and attractive dispersion between the cation and anion into the gas phase. By utilizing a well-curated set of protic ILs and molecular analogues, we successfully disentangled Coulomb interaction, hydrogen bonding, and dispersion interaction through purely thermodynamic methods.
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Affiliation(s)
- Peter Stange
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Albert-Einstein-Str. 27, 18059 Rostock, Germany
| | - Sergey P Verevkin
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Albert-Einstein-Str. 27, 18059 Rostock, Germany
| | - 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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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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Ando M, Koyakkat M, Ueda T, Minato T, Shirota H. Wettability and Surface Tension of Imidazolium, Ammonium, and Phosphonium Bis(fluorosulfonyl)amide Ionic Liquids: Comparison between Pentyl, Ethoxyethyl, and Ethylthioethyl Groups. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:12090-12098. [PMID: 37578197 DOI: 10.1021/acs.langmuir.3c01375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
This study particularly compares the surface tensions and contact angles for molten bis(fluorosulfonyl)amide salts of imidazolium, ammonium, and phosphonium cations with the pentyl, ethoxyethyl, or ethylthioethyl group. The examined substrate plates for contact angle measurements include silicate glass, platinum, copper, graphene, and polytetrafluoroethylene (PTFE). In addition, quantum chemistry calculations were performed to obtain the optimized structures of the cations and anions of the ionic liquids (ILs) that were studied here along with some typical anions and their dipole moments, mean polarizabilities, and charge distributions. All ILs showed the same order of contact angles with respect to the substrates: PTFE > graphene ≈ copper ≈ platinum > silicate glass. By comparing the three functional groups, i.e., pentyl, ethoxyethyl, and ethylthioethyl, the ILs with the ethylthioethyl group featured a higher work of adhesion than the respective ILs with the pentyl or ethoxyethyl group. The values of the surface tensions of the ILs followed the same trend for the three functional groups. Based on the Fowkes theory, it was found that the larger surface tensions of the ILs with the ethylthioethyl group compared with pentyl and ethoxyethyl groups were because of the increase in both dispersive and nondispersive components. The quantum chemistry calculations of the ions showed a larger dipole moment and mean polarizability for the cations with the ethylthioethyl group as compared with the pentyl and ethoxyethyl groups. This is consistent with the analysis results of the surface tensions based on the Fowkes theory. By comparing other anions, the dispersive component of the surface tension of the ILs with bis(fluorosulfonyl)amide was large, which is attributed to the small dipole moment of the anion.
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Affiliation(s)
- Masatoshi Ando
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
| | - Maharoof Koyakkat
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
| | - Tadashi Ueda
- Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
| | - Taketoshi Minato
- Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
| | - Hideaki Shirota
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
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Kim HJ. Spectroscopic and Chemical Properties of Ionic Liquids: Computational Study. CHEM REC 2023; 23:e202300075. [PMID: 37166396 DOI: 10.1002/tcr.202300075] [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: 02/27/2023] [Revised: 04/18/2023] [Indexed: 05/12/2023]
Abstract
A brief account is given of highlights of our computational efforts - often in collaboration with experimental groups - to understand spectroscopic and chemical properties of ionic liquids (ILs). Molecular dynamics, including their inhomogeneous character, responsible for key spectral features observed in dielectric absorption, infra-red (IR) and fluorescence correlation spectroscopy (FCS) measurements are elucidated. Mechanisms of chemical processes involving imidazolium-based ILs are illustrated for CO2 capture and related reactions, transesterification of cellulose, and Au nanocluster-catalyzed Suzuki cross-coupling reaction with attention paid to differing roles of IL ions. A comparison with experiments is also made.
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Affiliation(s)
- Hyung J Kim
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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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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Ando M, Tashiro A, Kawano M, Peng Y, Takamuku T, Shirota H. Exploring the Microscopic Aspects of 1-Methyl-3-octylimidazolium Tetrafluoroborate Mixtures with Formamide, N-Methylformamide, and N, N-Dimethylformamide by Multiple Spectroscopic Techniques and Computations. J Phys Chem B 2023; 127:3870-3887. [PMID: 37093658 DOI: 10.1021/acs.jpcb.2c09102] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
The microscopic aspects of 1-methyl-3-octylimidazolium tetrafluoroborate ([MOIm][BF4]) mixtures with formamide (FA), N-methylformamide (NMF), and N,N-dimethylformamide (DMF) were investigated using spectroscopic techniques of femtosecond Raman-induced Kerr effect spectroscopy (fs-RIKES), FT-IR, and NMR. Molecular dynamics simulations and quantum chemistry calculations were also performed. According to fs-RIKES, the first moment of the low-frequency spectrum bands mainly originating from the intermolecular vibrations in the [MOIm][BF4]/FA and [MOIm][BF4]/DMF systems changed gradually with the molecular liquid mole fraction XML but that in the [MOIm][BF4]/NMF system was constant up to XNMF = 0.7 and then gradually increased in the range of XNMF ≥ 0.7. Excluding the contribution of the 2D hydrogen-bonding network due to the presence of FA in the low-frequency spectrum band, the XML dependence of the normalized first moment of the low-frequency band in the [MOIm][BF4]/FA and [MOIm][BF4]/NMF systems revealed that the normalized first moment did not remarkably change in the range of XML < 0.7 but drastically increased in XML ≥ 0.7. FT-IR results indicated that the amide C═O band shifted to the low-frequency side with increasing XML for the three mixtures due to the hydrogen bonds. The imidazolium ring C-H band also showed a similar tendency to the amide C═O band. 19F NMR probed the microenvironment of [BF4]- in the mixtures. The [MOIm][BF4]/NMF and [MOIm][BF4]/DMF systems showed an up-field shift of the F atoms of the anion with increasing XML, and the [MOIm][BF4]/FA system exhibited a down-field shift. Steep changes in the chemical shifts were confirmed in the region of XML > 0.8. On the basis of the quantum chemistry calculations, the observed chemical shifts with increasing XML were mainly attributed to the many-body interactions of ions and amides for the [MOIm][BF4]/FA and [MOIm][BF4]/DMF systems. Meanwhile, the long distance between the cation and the anion was due to the high dielectric medium for the [MOIm][BF4]/NMF system, which led to an up-field shift.
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Affiliation(s)
- Masatoshi Ando
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
| | - Atsuya Tashiro
- Department of Chemistry and Applied Chemistry, Graduate School of Science and Engineering, Saga University, Honjo-machi, Saga 840-8502, Japan
| | - Masahiro Kawano
- Department of Chemistry and Applied Chemistry, Graduate School of Science and Engineering, Saga University, Honjo-machi, Saga 840-8502, Japan
| | - Yue Peng
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
| | - Toshiyuki Takamuku
- Faculty of Science and Engineering, Saga University, Honjo-machi, Saga 840-8502, Japan
| | - Hideaki Shirota
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
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Busch J, Kotwica D, Al Sheakh L, Headen T, Youngs TGA, Paschek D, Ludwig R. Quantification and Distribution of Three Types of Hydrogen Bonds in Mixtures of an Ionic Liquid with the Hydrogen-Bond-Accepting Molecular Solvent DMSO Explored by Neutron Diffraction and Molecular Dynamics Simulations. J Phys Chem Lett 2023; 14:2684-2691. [PMID: 36892277 DOI: 10.1021/acs.jpclett.3c00018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The concept of hydrogen bonding is celebrating its 100th birthday. Hydrogen bonds (H-bonds) play a key role in the structure and function of biological molecules, the strength of materials, and molecular binding. Herein, we study H-bonding in mixtures of a hydroxyl-functionalized ionic liquid with the neutral, H-bond-accepting molecular liquid dimethylsulfoxide (DMSO) using neutron diffraction experiments and molecular dynamics simulations. We report the geometry, strength, and distribution of three different types of H-bond OH···O, formed between the hydroxyl group of the cation and either the oxygen atom of another cation, the counteranion, or the neutral molecule. Such a variety of different strengths and distributions of H-bonds in one single mixture could hold the promise of providing solvents with potential applications in H-bond-related chemistry, for example, to alter the natural selectivity patterns of catalytic reactions or the conformation of catalysts.
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Affiliation(s)
- Johanna Busch
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Str. 27, 18059 Rostock, Germany
| | - David Kotwica
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Str. 27, 18059 Rostock, Germany
| | - Loai Al Sheakh
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Str. 27, 18059 Rostock, Germany
| | - Thomas Headen
- ISIS Faculty, STFC, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Tristan G A Youngs
- ISIS Faculty, STFC, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Dietmar Paschek
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Str. 27, 18059 Rostock, Germany
| | - Ralf Ludwig
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Str. 27, 18059 Rostock, Germany
- Department LL&M, Universität 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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10
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F. T. de Souza Í, C. C. Ribeiro M. Understanding ion-ion and ion-urea interactions in mixtures of urea and choline oxyanions salts. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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11
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Ando M, Ohta K, Ishida T, Koido R, Shirota H. Physical Properties and Low-Frequency Polarizability Anisotropy and Dipole Responses of Phosphonium Bis(fluorosulfonyl)amide Ionic Liquids with Pentyl, Ethoxyethyl, or 2-(Ethylthio)ethyl Group. J Phys Chem B 2023; 127:542-556. [PMID: 36602430 DOI: 10.1021/acs.jpcb.2c07466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
This study compared the physical properties, e.g., glass transition temperature, melting point, viscosity, density, surface tension, and electrical conductivity, and the low-frequency spectra under 200 cm-1 of three synthesized ionic liquids (ILs), triethylpentylphosphonium bis(fluorosulfonyl)amide ([P2225][NF2]), ethoxyethyltriethylphosphonium bis(fluorosulfonyl)amide ([P222(2O2)][NF2]), and triethyl[2-(ethylthio)ethyl]phosphonium bis(fluorosulfonyl)amide ([P222(2S2)][NF2]), at various temperatures using femtosecond Raman-induced Kerr effect spectroscopy (fs-RIKES) and terahertz time-domain spectroscopy (THz-TDS). The [P222(2S2)][NF2] had the highest viscosity and glass transition temperature, whereas the [P222(2O2)][NF2] had the lowest. Among the three ILs, the [P222(2S2)][NF2] had the highest density and surface tension, and the [P222(2O2)][NF2] had the highest electrical conductivity. The RIKES and THz-TDS spectral line shapes for the three ILs varied significantly. For the [P2225][NF2], molecular dynamics simulations successfully reproduced the line shapes of the experimental spectra and indicated that the RIKES spectrum was mainly due to the cation and cross-term and their rotational motions, whereas the THz-TDS spectrum was mainly due to the anion and its translational motion. This shows that it is desirable to utilize both fs-RIKES and THz-TDS methods to reveal molecular motions at the low-frequency domain. The [P222(2S2)][NF2] had higher frequency peaks and broader bands in the low-frequency spectra via fs-RIKES and THz-TDS than those for the [P2225][NF2] and [P222(2O2)][NF2].
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Affiliation(s)
- Masatoshi Ando
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
| | - Kaoru Ohta
- Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Tateki Ishida
- Department of Theoretical and Computational Molecular Science, Institute for Molecular Science and Research Center for Computational Science, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
| | - Ryohei Koido
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
| | - Hideaki Shirota
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
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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] [MESH Headings] [Grants] [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 CatalysisSiberian Branch of Russian Academy of SciencesProspekt Akademika Lavrentieva 5Novosibirsk630090Russia
- Novosibirsk State UniversityPirogova Street 2Novosibirsk630090Russia
| | - Peter Stange
- Universität RostockInstitut für ChemieAbteilung für Physikalische ChemieAlbert-Einstein-Straße 2718059RostockGermany
| | - Dietmar Paschek
- Universität RostockInstitut für ChemieAbteilung für Physikalische ChemieAlbert-Einstein-Straße 2718059RostockGermany
| | - Alexander G. Stepanov
- Boreskov Institute of CatalysisSiberian Branch of Russian Academy of SciencesProspekt Akademika Lavrentieva 5Novosibirsk630090Russia
| | - Daniil I. Kolokolov
- Boreskov Institute of CatalysisSiberian Branch of Russian Academy of SciencesProspekt Akademika Lavrentieva 5Novosibirsk630090Russia
- Novosibirsk State UniversityPirogova Street 2Novosibirsk630090Russia
| | - Ralf Ludwig
- Universität RostockInstitut für ChemieAbteilung für Physikalische ChemieAlbert-Einstein-Straße 2718059RostockGermany
- Leibniz-Institut für Katalyse an der Universität Rostock e.V.Albert-Einstein-Str. 29a18059RostockGermany
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13
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Yan F, Mukherjee K, Maroncelli M, Kim HJ. Infrared Spectroscopy of Li + Solvation in EmimBF 4 and in Propylene Carbonate: Ab Initio Molecular Dynamics and Experiment. J Phys Chem B 2022; 126:9643-9662. [DOI: 10.1021/acs.jpcb.2c06326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Fangyong Yan
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Kallol Mukherjee
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mark Maroncelli
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Hyung J. Kim
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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14
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A stability analysis of choline chloride: urea deep eutectic solvent using density functional theory. COMPUT THEOR CHEM 2022. [DOI: 10.1016/j.comptc.2022.113921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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15
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Structure of ethylammonium hydrogen sulfate protic ionic liquid through DFT calculations and MD simulations: the role of hydrogen bonds. Struct Chem 2022. [DOI: 10.1007/s11224-022-02042-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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16
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Hunger L, Al‐Sheakh L, Zaitsau DH, Verevkin SP, Appelhagen A, Villinger A, Ludwig R. Dissecting Noncovalent Interactions in Carboxyl-Functionalized Ionic Liquids Exhibiting Double and Single Hydrogens Bonds Between Ions of Like Charge. Chemistry 2022; 28:e202200949. [PMID: 35785500 PMCID: PMC9543318 DOI: 10.1002/chem.202200949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Indexed: 11/11/2022]
Abstract
We show that the carboxyl-functionalized ionic liquid 1-(carboxymethyl)pyridinium bis(trifluoromethylsulfonyl)imide [HOOC-CH2 -py][NTf2 ] exhibits three types of hydrogen bonding: the expected single hydrogen bonds between cation and anion, and, surprisingly, single and double hydrogen bonds between the cations, despite the repulsive Coulomb forces between the ions of like charge. Combining X-ray crystallography, differential scanning calorimetry, IR spectroscopy, thermodynamic methods and DFT calculations allows the analysis and characterization of all types of hydrogen bonding present in the solid, liquid and gaseous states of the ionic liquid (IL). We find doubly hydrogen bonded cationic dimers (c+ =c+ ) in the crystalline phase. With increasing temperature, this binding motif opens in the liquid and is replaced by (c+ -c+ -a- species, with a remaining single cationic hydrogen bond and an additional hydrogen bond between cation and anion. We provide clear evidence that the IL evaporates as hydrogen-bonded ion pairs (c+ -a- ) into the gas phase. The measured transition enthalpies allow the noncovalent interactions to be dissected and the hydrogen bond strength between ions of like charge to be determined.
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Affiliation(s)
- Lasse Hunger
- Institut für ChemieAbteilung für Physikalische ChemieUniversität RostockAlbert-Einstein-Str. 2718059RostockGermany
| | - Loai Al‐Sheakh
- Institut für ChemieAbteilung für Physikalische ChemieUniversität RostockAlbert-Einstein-Str. 2718059RostockGermany
| | - Dzmitry H. Zaitsau
- Institut für ChemieAbteilung für Physikalische ChemieUniversität RostockAlbert-Einstein-Str. 2718059RostockGermany
- Department LL&MUniversity of RostockAlbert-Einstein-Str. 2518059RostockGermany
| | - Sergey P. Verevkin
- Institut für ChemieAbteilung für Physikalische ChemieUniversität RostockAlbert-Einstein-Str. 2718059RostockGermany
- Department LL&MUniversity of RostockAlbert-Einstein-Str. 2518059RostockGermany
| | - Andreas Appelhagen
- Institut für ChemieAbteilung für Physikalische ChemieUniversität RostockAlbert-Einstein-Str. 2718059RostockGermany
| | - Alexander Villinger
- Institut für ChemieAbteilung für Anorganische ChemieUniversität RostockAlbert-Einstein-Str. 3a18059RostockGermany
| | - Ralf Ludwig
- Institut für ChemieAbteilung für Physikalische ChemieUniversität RostockAlbert-Einstein-Str. 2718059RostockGermany
- Department LL&MUniversity of RostockAlbert-Einstein-Str. 2518059RostockGermany
- Leibniz-Institut für Katalyse an der Universität Rostock e.V.Albert-Einstein-Str. 29a18059RostockGermany
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17
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Reis GSA, de Souza RM, Ribeiro MCC. Molecular Dynamics Simulation Study of the Far-Infrared Spectrum of a Deep Eutectic Solvent. J Phys Chem B 2022; 126:5695-5705. [PMID: 35858287 DOI: 10.1021/acs.jpcb.2c03277] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Deep eutectic solvents (DESs) are similar to ionic liquids (IL) in terms of physicochemical properties and technical uses. In ILs, far-infrared (FIR) spectroscopy has been utilized to reveal ionic interactions and even to produce a signature of the strengthening of the cation-anion hydrogen bond. However, for the situation of the DES, where the mixing of a salt and a molecular species makes the interplay between multiple intermolecular interactions even more complex, a full investigation of FIR spectra is still absent. In this work, the FIR spectrum of the DES, often referred to as ethaline, which is a 1:2 mixture of choline chloride and ethylene glycol, is calculated using classical molecular dynamics (MD) simulations and compared to experimental data. To explore the induced dipole effect on the computed FIR spectrum, MD simulations were run with both nonpolarizable and polarizable models. The calculation satisfactorily reproduces the position of the peak at ∼110 cm-1 and the bandwidth seen in the experimental FIR spectrum of ethaline. The MD simulations show that the charge current is the most important contributor to the FIR spectrum, but the cross-correlation between the charge current and dipole reorientation also plays a role in the polarizable model. The dynamics of the chloride-ethylene glycol correlation span a wide frequency range, with a maximum at ∼150 cm-1, but it participates as a direct mechanism only in the charge current-dipole reorientation cross-term. Anion correlations, whose dynamics are regulated via correlation with both ethylene glycol and choline, make the most significant contribution to the charge current mechanism. The MD simulations were also utilized to investigate the effect on the FIR spectrum of adding water to the DES and switching to a 1:1 composition.
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Affiliation(s)
- Gabriela S A Reis
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, 05513-970 São Paulo, São Paulo, Brazil
| | - Rafael M de Souza
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, 05513-970 São Paulo, São Paulo, Brazil
| | - Mauro C C Ribeiro
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, 05513-970 São Paulo, São Paulo, Brazil
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18
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Mukherjee K, Palchowdhury S, Maroncelli M. OH Stretching and Libration Bands of Solitary Water in Ionic Liquids and Dipolar Solvents Share a Single Dependence on Solvent Polarity. J Phys Chem B 2022; 126:4584-4598. [PMID: 35687693 DOI: 10.1021/acs.jpcb.2c02445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Ionic liquids are an emerging class of materials which are finding application in a variety of technologically important areas. Because of their hydrophilic character, at least a small concentration of water is often present when ionic liquids are used in practical applications. This study employs infrared spectroscopy in the OH stretching and libration regions together with DFT calculations to better characterize the state of dilute water in ionic liquids. Water mole fractions (xw ∼ 0.1) are chosen such that nearly all water occurs in monomeric form and spectra probe the solvation structure and dynamics of solitary water molecules. New data are reported for a series of 1-ethyl-3-methylimidazolium liquids [Im21][X] with X- = (C2F5)3F3P-, (CF3SO2)2N-, BF4-, B(CN)4-, CF3SO3-, C2H5SO4-, NO3-, SCN-, and CH3CO2-, as well as for the two 1-hexyl-3-methylimidazolium liquids [Im61][Cl] and [Im61][I]. For comparison, spectra are also recorded in a variety of dipolar solvents, and much of the available literature data are summarized, providing a comprehensive perspective on monomeric water in homogeneous solution. Most prior studies of dilute water in ionic liquids interpreted OH stretching spectra only in terms of water being specifically bonded to two anions in A-···H-O-H···A- type solvates. The more detailed analysis presented here indicates the additional presence of asymmetrically solvated water, which in some cases includes both singly solvated (A-···H-O-H) and more subtle forms of asymmetric solvation. The same pattern of solvation also pertains to dipolar solvents capable of accepting hydrogen bonds from water. No clear distinction is found between OH spectra in high-polarity conventional solvents and ionic liquids. In all solvents, OH frequencies are strongly correlated to measures of solvent basicity or hydrogen bond accepting ability. Far-infrared spectra of the water libration band also show common trends in ionic and dipolar solvents. Despite the different character of the libration and OH modes, the frequencies of these vibrations show virtually the same solvent dependence (apart from sign) except in weakly polar or nonpolar solvents.
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Affiliation(s)
- Kallol Mukherjee
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Sourav Palchowdhury
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mark Maroncelli
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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19
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Xue J, Wang Y, Liu F, Yang H, Lin B, Li Z, Jing Y, Li D, Hua H. Alkaloid dimers isolated from
Thalictrum baicalense
have antitumor activities. CHINESE J CHEM 2022. [DOI: 10.1002/cjoc.202200159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jingjing Xue
- Key Laboratory of Structure‐Based Drug Design & Discovery, Ministry of Education Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
- School of Traditional Chinese Materia Medica Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
| | - Yuetong Wang
- Key Laboratory of Structure‐Based Drug Design & Discovery, Ministry of Education Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
- Wuya College of Innovation Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
| | - Fangshen Liu
- Key Laboratory of Structure‐Based Drug Design & Discovery, Ministry of Education Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
- School of Traditional Chinese Materia Medica Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
| | - Hangao Yang
- Key Laboratory of Structure‐Based Drug Design & Discovery, Ministry of Education Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
- School of Traditional Chinese Materia Medica Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
| | - Bin Lin
- Key Laboratory of Structure‐Based Drug Design & Discovery, Ministry of Education Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
- School of Pharmaceutical Engineering Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
| | - Zhanlin Li
- Key Laboratory of Structure‐Based Drug Design & Discovery, Ministry of Education Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
- School of Traditional Chinese Materia Medica Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
| | - Yongkui Jing
- Key Laboratory of Structure‐Based Drug Design & Discovery, Ministry of Education Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
- Wuya College of Innovation Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
| | - Dahong Li
- Key Laboratory of Structure‐Based Drug Design & Discovery, Ministry of Education Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
- School of Traditional Chinese Materia Medica Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
| | - Huiming Hua
- Key Laboratory of Structure‐Based Drug Design & Discovery, Ministry of Education Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
- School of Traditional Chinese Materia Medica Shenyang Pharmaceutical University Shenyang 110016 People's Republic of China
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20
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Anggraini Y, Yusuf A, Wonorahardjo S, Kurnia D, Viridi S, Magdalena Sutjahja I. Role of C2 Methylation and Anion Type on the Physicochemical and Thermal Properties of Imidazolium-Based Ionic Liquids. ARAB J CHEM 2022. [DOI: 10.1016/j.arabjc.2022.103963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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21
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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] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Indexed: 11/11/2022]
Abstract
We report the complex phase behavior of the glass forming protic ionic liquid (PIL) d3-octylphosphonium bis(trifluoromethylsulfonyl)imide [C8 H17 PD3 ][NTf2 ] by means of solid-state NMR spectroscopy. Combined line shape and spin relaxation studies of the deuterons in the PD3 group of the octylphosphonium cation allow to map and correlate the phase behavior for a broad temperature range from 71 K to 343 K. In the solid PIL at 71 K, we observed a static state, characterized by the first deuteron quadrupole coupling constant reported for PD3 deuterons. A transition enthalpy of about 12 kJ mol-1 from the static to the mobile state with increasing temperature suggests the breaking of a weak, charge-enhanced hydrogen bond between cation and anion. The highly mobile phase above 100 K exhibits an almost disappearing activation barrier, strongly indicating quantum tunneling. Thus, we provide first evidence of tunneling driven mobility of the hydrogen bonded P-D moieties in the glassy state of PILs, already at surprisingly high temperatures up to 200 K. Above 250 K, the mobile phase turns from anisotropic to isotropic motion, and indicates strong internal rotation of the PD3 group. The analyzed line shapes and spin relaxation times allow us to link the structural and dynamical behavior at molecular level with the phase behavior beyond the DSC traces.
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Affiliation(s)
- Alexander E. Khudozhitkov
- Boreskov Institute of CatalysisSiberian Branch of Russian Academy of SciencesProspekt Akademika Lavrentieva 5Novosibirsk630090Russia
- Novosibirsk State UniversityPirogova Street 2Novosibirsk630090Russia
| | - Masaki Donoshita
- Division of ChemistryGraduate School of ScienceKyoto University Kitashirakawa-Oiwakecho, Sakyo-kuKyoto606-8502Japan
| | - Alexander G. Stepanov
- Boreskov Institute of CatalysisSiberian Branch of Russian Academy of SciencesProspekt Akademika Lavrentieva 5Novosibirsk630090Russia
- Novosibirsk State UniversityPirogova Street 2Novosibirsk630090Russia
| | - Frederik Philippi
- Physikalische ChemieUniversität des SaarlandesCampus B2.266123SaarbrückenGermany
| | - Daniel Rauber
- Physikalische ChemieUniversität des SaarlandesCampus B2.266123SaarbrückenGermany
| | - Rolf Hempelmann
- Physikalische ChemieUniversität des SaarlandesCampus B2.266123SaarbrückenGermany
| | - Hiroshi Kitagawa
- Division of ChemistryGraduate School of ScienceKyoto University Kitashirakawa-Oiwakecho, Sakyo-kuKyoto606-8502Japan
| | - Daniil I. Kolokolov
- Boreskov Institute of CatalysisSiberian Branch of Russian Academy of SciencesProspekt Akademika Lavrentieva 5Novosibirsk630090Russia
- Novosibirsk State UniversityPirogova Street 2Novosibirsk630090Russia
| | - Ralf Ludwig
- Department LL&MUniversity of RostockAlbert-Einstein-Str. 2518059RostockGermany
- Institut für ChemieAbteilung für Physikalische ChemieUniversität RostockDr.-Lorenz-Weg 218059RostockGermany
- Leibniz-Institut für KatalyseUniversität Rostock e.V.Albert-Einstein-Str. 29a18059RostockGermany
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22
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Aprotic Ionic Liquids: A Framework for Predicting Vaporization Thermodynamics. Molecules 2022; 27:molecules27072321. [PMID: 35408720 PMCID: PMC9000287 DOI: 10.3390/molecules27072321] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/29/2022] [Accepted: 04/01/2022] [Indexed: 11/16/2022] Open
Abstract
Ionic liquids (ILs) are recognized as an environmentally friendly alternative to replacing volatile molecular solvents. Knowledge of vaporization thermodynamics is crucial for practical applications. The vaporization thermodynamics of five ionic liquids containing a pyridinium cation and the [NTf2] anion were studied using a quartz crystal microbalance. Vapor pressure-temperature dependences were used to derive the enthalpies of vaporization of these ionic liquids. Vaporization enthalpies of the pyridinium-based ionic liquids available in the literature were collected and uniformly adjusted to the reference temperature T = 298.15 K. The consistent sets of evaluated vaporization enthalpies were used to develop the “centerpiece”-based group-additivity method for predicting enthalpies of vaporization of ionic compounds. The general transferability of the contributions to the enthalpy of vaporization from the molecular liquids to the ionic liquids was established. A small, but not negligible correction term was supposed to reconcile the estimated results with the experiment. The corrected “centerpiece” approach was recommended to predict the vaporization enthalpies of ILs.
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23
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Kumar P, Pandey DK, Parwani AK, Singh DK. A comprehensive multidisciplinary investigation on CO 2 capture from diesel engine. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:26409-26424. [PMID: 34859350 DOI: 10.1007/s11356-021-17812-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 11/23/2021] [Indexed: 05/27/2023]
Abstract
Climate change and global warming are the visible consequences of the increased amount of carbon dioxide (CO2) in the atmosphere. Among the various sources of anthropogenic CO2 emission, the diesel engine has a significant contribution. The development of a reliable system to efficiently minimize CO2 emissions from diesel engines to the safest level is lacking in the open literature. Therefore, a comprehensive multidisciplinary approach has been applied in this paper to investigate the efficacy of the post-combustion carbon capture (PCC) process for the diesel engine. The experiments have been performed on the exhaust of a direct injection diesel engine at five different brake powers with blends of aqueous ammonia (AQ_NH3), monoethanolamine (MEA), N,N-dimethylethanolamine (DMEA), and 1-ethyl-3-methylimidazolium tetrafluoroborate (C2mim BF4) ionic liquid (IL) as an absorbent for CO2 capture. The reaction mechanism of these absorbent with CO2 are also studied by the geometrical, energetical, MESP, frontier molecular orbitals, and NBO analysis using the first-principles density functional theory (DFT) calculations. The maximum CO2 absorption efficiency of almost 97% was achieved for the blend consisting of 67% of AQ_NH3 and 33% of MEA. Moreover, AQ_MEA and blend of AQ_NH3, DMEA, and C2mim BF4 ionic liquid showed 96% and 94% CO2 absorption efficiency, respectively.
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Affiliation(s)
- Pulkit Kumar
- Department of Mechanical and Aero-Space Engineering, Institute of Infrastructure Technology Research And Management, Ahmedabad, 380026, India
| | - Deepak K Pandey
- Department of Basic Sciences, Institute of Infrastructure Technology Research And Management, Ahmedabad, 380026, India
| | - Ajit Kumar Parwani
- Department of Mechanical and Aero-Space Engineering, Institute of Infrastructure Technology Research And Management, Ahmedabad, 380026, India.
| | - Dheeraj K Singh
- Department of Basic Sciences, Institute of Infrastructure Technology Research And Management, Ahmedabad, 380026, India
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24
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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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25
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Shmukler LE, Fedorova IV, Fadeeva Y, Gruzdev MS, Safonova LP. Alkylimidazolium Protic Ionic Liquids: Structural Features and Physicochemical Properties. Chemphyschem 2021; 23:e202100772. [PMID: 34904777 DOI: 10.1002/cphc.202100772] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/04/2021] [Indexed: 11/08/2022]
Abstract
We focus on a series of protic ionic liquids (PILs) with imidazolium and alkylimidazolium (1R3HIm, R = methyl, ethyl, propyl, and butyl) cations. Using the literature data and our experimental results on the thermal and transport properties, we analyze the effects of the anion nature and the alkyl radical length in the cation structure on the above properties. DFT calculations in gas and solvent phase have resulted in microscopic insights into the structure and cation-anion binding in these PILs. We show that the higher thermodynamic stability of an ion pair raises the PIL decomposition temperature. The melting points of the salts with the same cation decrease as the hydrocarbon radical in the cation becomes longer, which correlates with the weaker ion-ion interaction in the ion pairs. A comparative analysis of the protic ILs and corresponding ILs (1R3MeIm) with the same radical (R) in the cation structure and the same anion has been performed. The lower melting points of the ILs with 1R3MeIm cations are assumed to result from the weakening both of the ion-ion interaction and hydrogen bond.
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Affiliation(s)
- Liudmila E Shmukler
- G A Krestov Institute of Solution Chemistry Russian Academy of Sciences: Institut himii rastvorov imeni G A Krestova Rossijskoj akademii nauk, laboratory 1-8, RUSSIAN FEDERATION
| | - Irina V Fedorova
- G A Krestov Institute of Solution Chemistry Russian Academy of Sciences: Institut himii rastvorov imeni G A Krestova Rossijskoj akademii nauk, laboratory 1-8, RUSSIAN FEDERATION
| | - Yuliya Fadeeva
- G A Krestov Institute of Solution Chemistry Russian Academy of Sciences: Institut himii rastvorov imeni G A Krestova Rossijskoj akademii nauk, laboratory 1-8, Akademicheskaya, 1, 153045, Ivanovo, RUSSIAN FEDERATION
| | - Matvey S Gruzdev
- G A Krestov Institute of Solution Chemistry Russian Academy of Sciences: Institut himii rastvorov imeni G A Krestova Rossijskoj akademii nauk, laboratory 1-8, RUSSIAN FEDERATION
| | - Liubov P Safonova
- G A Krestov Institute of Solution Chemistry Russian Academy of Sciences: Institut himii rastvorov imeni G A Krestova Rossijskoj akademii nauk, laboratory 1-8, RUSSIAN FEDERATION
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26
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Verevkin SP, Kondratev SO, Zaitsau DH, Zherikova KV, Ludwig R. Quantification and understanding of non-covalent interactions in molecular and ionic systems: Dispersion interactions and hydrogen bonding analysed by thermodynamic methods. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117547] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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27
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Vázquez-Fernández I, Drużbicki K, Fernandez-Alonso F, Mukhopadhyay S, Nockemann P, Parker SF, Rudić S, Stana SM, Tomkinson J, Yeadon DJ, Seddon KR, Plechkova NV. Spectroscopic Signatures of Hydrogen-Bonding Motifs in Protonic Ionic Liquid Systems: Insights from Diethylammonium Nitrate in the Solid State. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:24463-24476. [PMID: 34795809 PMCID: PMC8592064 DOI: 10.1021/acs.jpcc.1c05137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 10/08/2021] [Indexed: 06/13/2023]
Abstract
Diethylammonium nitrate, [N0 0 2 2][NO3], and its perdeuterated analogue, [N D D 2 2] [NO3], were structurally characterized and studied by infrared, Raman, and inelastic neutron scattering (INS) spectroscopy. Using these experimental data along with state-of-the-art computational materials modeling, we report unambiguous spectroscopic signatures of hydrogen-bonding interactions between the two counterions. An exhaustive assignment of the spectral features observed with each technique has been provided, and a number of distinct modes related to NH···O dynamics have been identified. We put a particular emphasis on a detailed interpretation of the high-resolution, broadband INS experiments. In particular, the INS data highlight the importance of conformational degrees of freedom within the alkyl chains, a ubiquitous feature of ionic liquid (IL) systems. These findings also enable an in-depth physicochemical understanding of protonic IL systems, a first and necessary step to the tailoring of hydrogen-bonding networks in this important class of materials.
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Affiliation(s)
- Isabel Vázquez-Fernández
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, Belfast BT9 5AG, Northern Ireland, U.K.
| | - Kacper Drużbicki
- Materials
Physics Center, CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, Donostia-San
Sebastian 20018, Spain
- Centre
of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, Lodz 90-363, Poland
| | - Felix Fernandez-Alonso
- Materials
Physics Center, CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, Donostia-San
Sebastian 20018, Spain
- Donostia
International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San
Sebastian 20018, Spain
- Department
of Physics and Astronomy, University College
London, Gower Street, London WC1E 6BT, U.K.
- Ikerbasque,
Basque Foundation for Science, Plaza Euskadi 5, Bilbao 48009, Spain
| | - Sanghamitra Mukhopadhyay
- ISIS
Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, U.K.
- Department
of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
| | - Peter Nockemann
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, Belfast BT9 5AG, Northern Ireland, U.K.
| | - Stewart F. Parker
- ISIS
Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, U.K.
| | - Svemir Rudić
- ISIS
Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, U.K.
| | - Simona-Maria Stana
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, Belfast BT9 5AG, Northern Ireland, U.K.
| | - John Tomkinson
- ISIS
Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, U.K.
| | - Darius J. Yeadon
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, Belfast BT9 5AG, Northern Ireland, U.K.
| | - Kenneth R. Seddon
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, Belfast BT9 5AG, Northern Ireland, U.K.
| | - Natalia V. Plechkova
- The
QUILL Research Centre, School of Chemistry and Chemical Engineering, The Queen’s University of Belfast, Belfast BT9 5AG, Northern Ireland, U.K.
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28
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Tran L, Rush K, Marzette J, Edmonds-Andrews G, Bennett T, Abdulahad A, Riley KE, Dutta S. Striking temperature-dependent molecular reorganization at the C-2 position of [EMIM][BF4]. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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29
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Wu X, Zhu Q, Chen Z, Wu W, Lu Y, Qi J. Ionic liquids as a useful tool for tailoring active pharmaceutical ingredients. J Control Release 2021; 338:268-283. [PMID: 34425167 DOI: 10.1016/j.jconrel.2021.08.032] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 02/06/2023]
Abstract
Ionic liquids (ILs) have been widely used in biomedical and pharmaceutical fields as solvents or permeation enhancers. Recently, more and more researchers focused on optimizing the physicochemical properties of active pharmaceutical ingredient (API) by ILs technology. Converting APIs into ILs (API-ILs) has shown great potential for drug delivery by eliminating polymorphism, tailoring solubility, improving thermal stability, increasing dissolution, controlling drug release, modulating the surfactant properties, enhancing permeability of APIs and modulating cytotoxicity on tumor cells. In addition, API-ILs are also used in various formulations as active ingredients, such as solutions, emulsions, even tablets or nanoparticles. This paper aims to review current status of API-ILs, including the rational and design, preparation and characterization, the improvement on the physicochemical characteristics of APIs, the compatibility of API-ILs with various formulations, and the future prospects of API-ILs in biomedical and pharmaceutical fields.
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Affiliation(s)
- Xiying Wu
- Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai 200443, China; Key Laboratory of Smart Drug Delivery of MOE, School of Pharmacy, Fudan University, Shanghai 201203, China
| | - Quangang Zhu
- Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai 200443, China
| | - Zhongjian Chen
- Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai 200443, China
| | - Wei Wu
- Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai 200443, China; Key Laboratory of Smart Drug Delivery of MOE, School of Pharmacy, Fudan University, Shanghai 201203, China
| | - Yi Lu
- Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai 200443, China; Key Laboratory of Smart Drug Delivery of MOE, School of Pharmacy, Fudan University, Shanghai 201203, China
| | - Jianping Qi
- Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai 200443, China; Key Laboratory of Smart Drug Delivery of MOE, School of Pharmacy, Fudan University, Shanghai 201203, China.
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30
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Filippov A, Alexandrov AS, Gimatdinov R, Ullah Shah F. Unusual ion transport behaviour of ethylammonium nitrate mixed with lithium nitrate. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116841] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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31
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Al Sheakh L, Niemann T, Villinger A, Stange P, Zaitsau DH, Strate A, Ludwig R. Three in One: The Versatility of Hydrogen Bonding Interaction in Halide Salts with Hydroxy-Functionalized Pyridinium Cations. Chemphyschem 2021; 22:1850-1856. [PMID: 34241946 PMCID: PMC8518508 DOI: 10.1002/cphc.202100424] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/08/2021] [Indexed: 11/28/2022]
Abstract
The paradigm of supramolecular chemistry relies on the delicate balance of noncovalent forces. Here we present a systematic approach for controlling the structural versatility of halide salts by the nature of hydrogen bonding interactions. We synthesized halide salts with hydroxy-functionalized pyridinium cations [HOCn Py]+ (n=2, 3, 4) and chloride, bromide and iodide anions, which are typically used as precursor material for synthesizing ionic liquids by anion metathesis reaction. The X-ray structures of these omnium halides show two types of hydrogen bonding: 'intra-ionic' H-bonds, wherein the anion interacts with the hydroxy group and the positively charged ring at the same cation, and 'inter-ionic' H-bonds, wherein the anion also interacts with the hydroxy group and the ring system but of different cations. We show that hydrogen bonding is controllable by the length of the hydroxyalkyl chain and the interaction strength of the anion. Some molten halide salts exhibit a third type of hydrogen bonding. IR spectra reveal elusive H-bonds between the OH groups of cations, showing interaction between ions of like charge. They are formed despite the repulsive interaction between the like-charged ions and compete with the favored cation-anion H-bonds. All types of H-bonding are analyzed by quantum chemical methods and the natural bond orbital approach, emphasizing the importance of charge transfer in these interactions. For simple omnium salts, we evidenced three distinct types of hydrogen bonds: Three in one!
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Affiliation(s)
- Loai Al Sheakh
- Universität RostockInstitut für Chemie, Abteilung für Physikalische ChemieDr.-Lorenz-Weg 218059RostockGermany
| | - Thomas Niemann
- Universität RostockInstitut für Chemie, Abteilung für Physikalische ChemieDr.-Lorenz-Weg 218059RostockGermany
| | - Alexander Villinger
- Institut für Chemie, Abteilung für Anorganische ChemieUniversität RostockAlbert-Einstein-Strasse 3a18059RostockGermany
| | - Peter Stange
- Universität RostockInstitut für Chemie, Abteilung für Physikalische ChemieDr.-Lorenz-Weg 218059RostockGermany
| | - Dzmitry H. Zaitsau
- Universität RostockInstitut für Chemie, Abteilung für Physikalische ChemieDr.-Lorenz-Weg 218059RostockGermany
- Department LL&MUniversity of RostockAlbert-Einstein-Str. 2518059RostockGermany
| | - Anne Strate
- Universität RostockInstitut für Chemie, Abteilung für Physikalische ChemieDr.-Lorenz-Weg 218059RostockGermany
- Department LL&MUniversity of RostockAlbert-Einstein-Str. 2518059RostockGermany
| | - Ralf Ludwig
- Universität RostockInstitut für Chemie, Abteilung für Physikalische ChemieDr.-Lorenz-Weg 218059RostockGermany
- Department LL&MUniversity of RostockAlbert-Einstein-Str. 2518059RostockGermany
- Leibniz-Institut für Katalyse an der Universität Rostock e.V.Albert-Einstein-Str. 29a18059RostockGermany
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32
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Shelepova EA, Ludwig R, Paschek D, Medvedev NN. Structural similarity of an ionic liquid and the mixture of the neutral molecules. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115589] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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33
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Golub B, Fumino K, Stange P, Fossog V, Hempelmann R, Ondo D, Paschek D, Ludwig R. Balance Between Contact and Solvent-Separated Ion Pairs in Mixtures of the Protic Ionic Liquid [Et 3NH][MeSO 3] with Water Controlled by Water Content and Temperature. J Phys Chem B 2021; 125:4476-4488. [PMID: 33899479 DOI: 10.1021/acs.jpcb.1c01850] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The formation of aggregates of ionic species is a crucial process in liquids and solutions. Ion speciation is particularly interesting for the case of ionic liquids (ILs) since these Coulombic fluids consist solely of ions. Most of their unique properties, such as enthalpies of vaporization and conductivities, are strongly related to ion pair formation. Here, we show that the balance of hydrogen-bonded contact ion pairs (CIP) and solvent-separated (SIP) ion pairs in protic ionic liquids (PILs) and in their mixtures with water can be well understood by a combination of far-infrared (FIR) and mid-infrared (MIR) spectroscopy, density functional theory (DFT) calculations of PIL/water aggregates, and molecular dynamics (MD) simulations of PIL/water mixtures. This combined approach is applied to mixtures of triethylammonium methanesulfonate [Et3NH][MeSO3] with water. It is shown that ion speciation in this mixture depends on three parameters: the relative hydrogen bond acceptor strength of the counter ion and the molecular solvent, the solvent concentration, and the temperature. For selected PIL/water mixtures, the equilibrium constants for CIPs and SIPs were determined as a function of the solvent content and temperature. Finally, for the studied PIL/water mixtures, the transition from CIPs to SIPs could be understood on enthalpic and entropic grounds. A detailed picture of this interconversion process could be described at the molecular level by means of MD simulations. In addition, the concentration dependence of ion pair formation can be well understood with help of a simplified "cartoon-like" statistical model describing hydrogen bond redistribution.
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Affiliation(s)
- Benjamin Golub
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Straße 21, D-18059 Rostock, Germany
| | - Koichi Fumino
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, D-18059 Rostock, Germany
| | - Peter Stange
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, D-18059 Rostock, Germany
| | - Verlaine Fossog
- Transfercenter Sustainable Electrochemistry, Saarland University and KIST Europe, D-66123 Saarbrücken, Germany
| | - Rolf Hempelmann
- Transfercenter Sustainable Electrochemistry, Saarland University and KIST Europe, D-66123 Saarbrücken, Germany
| | - Daniel Ondo
- Department of Physical Chemistry, University of Chemistry and Technology, Technicka 5, CZ-166 28 Prague 6, Czech Republic
| | - Dietmar Paschek
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Straße 21, D-18059 Rostock, Germany
| | - Ralf Ludwig
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, D-18059 Rostock, Germany.,Leibniz Institut für Katalyse an der Universität Rostock, Albert-Einstein-Straße 29a, D-18059 Rostock, Germany
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34
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Fedorova I, Krestyaninov M, Safonova L. Structure and ion-ion interactions in trifluoroacetate-based ionic liquids: Quantum chemical and molecular dynamics simulation studies. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115449] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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35
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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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36
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Wang Y, Wen Z, Zhang Y, Wang X, Yao J, Li H. Aerobic α-hydroxylation of 2-Me-1-tetralone in 1-alkyl-3-methylimidazolium ionic liquids. Phys Chem Chem Phys 2021; 23:5864-5869. [PMID: 33687394 DOI: 10.1039/d0cp06047j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The aerobic α-hydroxylation of 2-Me-1-tetralone was investigated in imidazol-based ionic liquids (ILs), where reactions in 1-alkyl-3-methylimidazolium tetrafluoroborates were found to generate considerable products. By correlating the conversion at 2 h with viscosity, relative permittivity and the ET(30) value of ILs, we found that the local polarity in ILs represented by the ET(30) value or the chemical shift of α-proton at the substrate was the critical factor influencing the reaction rate. Furthermore, two-dimensional nuclear Overhauser effect spectroscopy (2D NOESY) was used to characterize the distribution of 2-Me-1-tetralone in ILs. As a result, the mesoscopic structures in ILs were recommended to have crucial influences on the distribution of the substrate in ILs, and the caused local polarity could affect the activation of 2-Me-1-tetralone. These findings revealed the solvent effects of ILs with different structures on the α-hydroxylation of 2-Me-1-tetralone, and may encourage the explorations of more types of aerobic oxidations in ILs.
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Affiliation(s)
- Yongtao Wang
- Department of Chemistry, ZJU-NHU United R&D Center, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China. and Center of Chemistry for Frontier Technologies, Zhejiang University, Hangzhou, 310027, China
| | - Zeyu Wen
- Department of Chemistry, ZJU-NHU United R&D Center, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China. and Center of Chemistry for Frontier Technologies, Zhejiang University, Hangzhou, 310027, China
| | - Yue Zhang
- Department of Chemistry, ZJU-NHU United R&D Center, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China.
| | - Xinyu Wang
- Department of Chemistry, ZJU-NHU United R&D Center, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China.
| | - Jia Yao
- Department of Chemistry, ZJU-NHU United R&D Center, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China.
| | - Haoran Li
- Department of Chemistry, ZJU-NHU United R&D Center, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China. and State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
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37
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Mariani A, Bonomo M, Gao X, Centrella B, Nucara A, Buscaino R, Barge A, Barbero N, Gontrani L, Passerini S. The unseen evidence of Reduced Ionicity: The elephant in (the) room temperature ionic liquids. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.115069] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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38
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Choi YJ, Takahashi T, Taki M, Sawada K, Takahashi K. Label-free attomolar protein detection using a MEMS optical interferometric surface-stress immunosensor with a freestanding PMMA/parylene-C nanosheet. Biosens Bioelectron 2021; 172:112778. [PMID: 33157412 DOI: 10.1016/j.bios.2020.112778] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 11/26/2022]
Abstract
We demonstrated an optical interferometer-based surface-stress immunosensor using freestanding polymethyl methacrylate (PMMA)/parylene-C nanosheet with high sensitivity for detection of biomolecules. PMMA/parylene-C nanosheets were transferred onto a silicon substrate with microcavities to fabricate freestanding submicron-thick membrane with a sealed cavity structure. The adhesive force between the transferred parylene-C and binder parylene-C layer was measured to be 1.06-2.4 N/10 mm by tape test. Evading Debye shielding, these nanomechanical sensors allow detection of the adsorption on the membrane surface through changes in surface stress transduced by the electric charge. We optimized the density of receptors and mode of immobilization for high sensitivity. To evaluate the selectivity of the sensor, membrane deflections induced by various proteins were measured and the spectral shifts showed high selectivity only for the target antigen. The minimum limit of detection (LOD) of the sensor for human serum albumin antigen was 0.1-1 fg/mL (1.5-15 aM), which was 20,000 times lower than that of the conventional micro-cantilever sensor.
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Affiliation(s)
- Yong-Joon Choi
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempakucho, Toyohashi, Aichi, 441-8580, Japan.
| | - Toshiaki Takahashi
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempakucho, Toyohashi, Aichi, 441-8580, Japan
| | - Miki Taki
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempakucho, Toyohashi, Aichi, 441-8580, Japan
| | - Kazuaki Sawada
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempakucho, Toyohashi, Aichi, 441-8580, Japan
| | - Kazuhiro Takahashi
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempakucho, Toyohashi, Aichi, 441-8580, Japan.
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39
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Atamas N, Bakumenko M. Dynamics of nonpolar molecules in dimethyl-imidazolium chloride. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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40
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Yu SS, Zhao HR, Shi JH, Zhang H, Duan HB. Synthesis, structure and Hirshfeld surface analysis of a series of novel low melting salts without alkyl groups. CrystEngComm 2021. [DOI: 10.1039/d1ce00933h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of 1-aminopyridinium base derivative ionic liquids without alkyl groups were synthesized. Hirshfeld surface analysis was used to understand the intricacies of interactions.
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Affiliation(s)
- Shan-Shan Yu
- Key laboratory of Advanced Functional Materials of Nanjing, Nanjing Xiaozhuang University, Nanjing 211171, P. R. China
| | - Hai-Rong Zhao
- School of Environmental Science, Nanjing Xiaozhuang University, Nanjing 211171, P. R. China
| | - Jian-Han Shi
- School of Environmental Science, Nanjing Xiaozhuang University, Nanjing 211171, P. R. China
| | - Hui Zhang
- Key laboratory of Advanced Functional Materials of Nanjing, Nanjing Xiaozhuang University, Nanjing 211171, P. R. China
| | - Hai-Bao Duan
- Key laboratory of Advanced Functional Materials of Nanjing, Nanjing Xiaozhuang University, Nanjing 211171, P. R. China
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41
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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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42
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Shirota H, Ando M, Kakinuma S, Takahashi K. Ultrafast Dynamics in Nonaromatic Cation Based Ionic Liquids: A Femtosecond Raman-Induced Kerr Effect Spectroscopic Study. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2020. [DOI: 10.1246/bcsj.20200198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Hideaki Shirota
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
| | - Masatoshi Ando
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
| | - Shohei Kakinuma
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
| | - Kotaro Takahashi
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
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43
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Philipp JK, Ludwig R. Clusters of Hydroxyl-Functionalized Cations Stabilized by Cooperative Hydrogen Bonds: The Role of Polarizability and Alkyl Chain Length. Molecules 2020; 25:E4972. [PMID: 33121087 PMCID: PMC7662246 DOI: 10.3390/molecules25214972] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 10/22/2020] [Accepted: 10/24/2020] [Indexed: 01/08/2023] Open
Abstract
We explore quantum chemical calculations for studying clusters of hydroxyl-functionalized cations kinetically stabilized by hydrogen bonding despite strongly repulsive electrostatic forces. In a comprehensive study, we calculate clusters of ammonium, piperidinium, pyrrolidinium, imidazolium, pyridinium, and imidazolium cations, which are prominent constituents of ionic liquids. All cations are decorated with hydroxy-alkyl chains allowing H-bond formation between ions of like charge. The cluster topologies comprise linear and cyclic clusters up to the size of hexamers. The ring structures exhibit cooperative hydrogen bonds opposing the repulsive Coulomb forces and leading to kinetic stability of the clusters. We discuss the importance of hydrogen bonding and dispersion forces for the stability of the differently sized clusters. We find the largest clusters when hydrogen bonding is maximized in cyclic topologies and dispersion interaction is properly taken into account. The kinetic stability of the clusters with short-chained cations is studied for the different types of cations ranging from hard to polarizable or exhibiting additional functional groups such as the acidic C(2)-H position in the imidazolium-based cation. Increasing the alkyl chain length, the cation effect diminishes and the kinetic stability is exclusively governed by the alkyl chain tether increasing the distance between the positively charged rings of the cations. With adding the counterion tetrafluoroborate (BF4-) to the cationic clusters, the binding energies immediately switch from strongly positive to strongly negative. In the neutral clusters, the OH functional groups of the cations can interact either with other cations or with the anions. The hexamer cluster with the cyclic H-bond motive and "released" anions is almost as stable as the hexamer built by H-bonded ion pairs exclusively, which is in accord with recent IR spectra of similar ionic liquids detecting both types of hydrogen bonding. For the cationic and neutral clusters, we discuss geometric and spectroscopic properties as sensitive probes of opposite- and like-charge interaction. Finally, we show that NMR proton chemical shifts and deuteron quadrupole coupling constants can be related to each other, allowing to predict properties which are not easily accessible by experiment.
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Affiliation(s)
- Jule K. Philipp
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, 18059 Rostock, Germany;
| | - Ralf Ludwig
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, 18059 Rostock, Germany;
- Department Life, Light & Matter, Universität 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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44
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Abstract
The extent to which cations and anions in ionic liquids (ILs) and ionic liquid solutions are dissociated is of both fundamental scientific interest and practical importance because ion dissociation has been shown to impact viscosity, density, surface tension, volatility, solubility, chemical reactivity, and many other important chemical and physical properties. When mixed with solvents, ionic liquids provide the unique opportunity to investigate ion dissociation from infinite dilution in the solvent to a completely solvent-free state, even at ambient conditions. The most common way to estimate ion dissociation in ILs and IL solutions is by comparing the molar conductivity determined from ionic conductivity measurements such as electrochemical impedance spectroscopy (EIS) (which measure the movement of only the charged, i.e., dissociated, ions) with the molar conductivity calculated from ion diffusivities measured by pulse field gradient nuclear magnetic resonance spectroscopy (PFG-NMR, which gives movement of all of the ions). Because the NMR measurements are time-consuming, the number of ILs and IL solutions investigated by this method is relatively limited. We have shown that use of the Stokes-Einstein equation with estimates of the effective ion Stokes radii allows ion dissociation to be calculated from easily measured density, viscosity, and ionic conductivity data (ρ, η, λ), which is readily available in the literature for a much larger number of pure ILs and IL solutions. Therefore, in this review, we present values of ion dissociation for ILs and IL solutions (aqueous and nonaqueous) determined by both the traditional molar conductivity/PFG-NMR method and the ρ, η, λ method. We explore the effect of cation and anion alkyl chain length, structure, and interaction motifs of the cation and anion, temperature, and the strength of the solvent in IL solutions.
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Affiliation(s)
- Oscar Nordness
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Joan F Brennecke
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
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45
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López-Bueno C, Bittermann MR, Dacuña-Mariño B, Llamas-Saiz AL, Del Carmen Giménez-López M, Woutersen S, Rivadulla F. Low temperature glass/crystal transition in ionic liquids determined by H-bond vs. coulombic strength. Phys Chem Chem Phys 2020; 22:20524-20530. [PMID: 32966417 DOI: 10.1039/d0cp02633f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Self-assembled ionic liquid crystals are anisotropic ionic conductors, with potential applications in areas as important as solar cells, battery electrolytes and catalysis. However, many of these applications are still limited by the lack of precise control over the variety of phases that can be formed (nematic, smectic, or semi/fully crystalline), determined by a complex pattern of different intermolecular interactions. Here we report the results of a systematic study of crystallization of several imidazolium salts in which the relative contribution of isotropic coulombic and directional H-bond interactions is carefully tuned. Our results demonstrate that the relative strength of directional H-bonds with respect to the isotropic Coulomb interaction determines the formation of a crystalline, semi-crystalline or glassy phase at low temperature. The possibility of pinpointing H-bonding directionality in ionic liquids make them model systems to study the crystallization of an ionic solid under a perturbed Coulomb potential.
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Affiliation(s)
- Carlos López-Bueno
- CIQUS, Centro de Investigación en Química Biolóxica e Materiais Moleculares, Universidade de Santiago de Compostela, 15782-Santiago de Compostela, Spain.
| | - Marius R Bittermann
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bruno Dacuña-Mariño
- X-Ray Unit, RIAIDT, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | | | - María Del Carmen Giménez-López
- CIQUS, Centro de Investigación en Química Biolóxica e Materiais Moleculares, Universidade de Santiago de Compostela, 15782-Santiago de Compostela, Spain. and Departamento de Química-Inorgánica, Universidade de Santiago de Compostela, 15782-Santiago de Compostela, Spain
| | - Sander Woutersen
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Francisco Rivadulla
- CIQUS, Centro de Investigación en Química Biolóxica e Materiais Moleculares, Universidade de Santiago de Compostela, 15782-Santiago de Compostela, Spain. and Departamento de Química-Física, Universidade de Santiago de Compostela, 15782-Santiago de Compostela, Spain
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46
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Ando M, Kawano M, Tashiro A, Takamuku T, Shirota H. Low-Frequency Spectra of 1-Methyl-3-octylimidazolium Tetrafluoroborate Mixtures with Methanol, Acetonitrile, and Dimethyl Sulfoxide: A Combined Study of Femtosecond Raman-Induced Kerr Effect Spectroscopy and Molecular Dynamics Simulations. J Phys Chem B 2020; 124:7857-7871. [DOI: 10.1021/acs.jpcb.0c04870] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Masatoshi Ando
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
| | - Masahiro Kawano
- Department of Chemistry and Applied Chemistry, Graduate School of Science and Engineering, Saga University, Honjo-machi, Saga 840-8502, Japan
| | - Atsuya Tashiro
- Department of Chemistry and Applied Chemistry, Graduate School of Science and Engineering, Saga University, Honjo-machi, Saga 840-8502, Japan
| | - Toshiyuki Takamuku
- Faculty of Science and Engineering, Saga University, Honjo-machi, Saga 840-8502, Japan
| | - Hideaki Shirota
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
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47
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Khudozhitkov AE, Niemann T, Stange P, Donoshita M, Stepanov AG, Kitagawa H, Kolokolov DI, Ludwig R. Freezing the Motion in Hydroxy-Functionalized Ionic Liquids-Temperature Dependent NMR Deuteron Quadrupole Coupling Constants for Two Types of Hydrogen Bonds Far below the Glass Transition. J Phys Chem Lett 2020; 11:6000-6006. [PMID: 32640795 DOI: 10.1021/acs.jpclett.0c01731] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We measured the deuteron quadrupole coupling constants (DQCCs) for hydroxy-functionalized ionic liquids (ILs) with varying alkyl chain length over the temperature range between 60 and 200 K by means of solid-state NMR spectroscopy. For all temperatures, the 2H spectra show two DQCCs representing different types of hydrogen bonds. Higher values, ranging from 220 to 250 kHz, indicate weaker hydrogen bonds between cation and anion (c-a), and lower values varying from 165 to 210 kHz result from stronger hydrogen bonds between the OD groups of cations (c-c), in agreement with recent observations in infrared, neutron diffraction, and NMR studies. We observed different temperature dependencies for (c-a) and (c-c) hydrogen bonding. From the static pattern of the 2H spectra at the lowest temperatures, we derived the true DQCCs being up to 20 kHz larger than recently reported values measured at the glass transition temperature. We were able to freeze the librational motions of the hydrogen bonds in the ILs. The temperature dependence of the (c-a) and (c-c) cluster populations in the glassy state is opposite to that observed in the liquid state, partly anticipating the behavior of ILs tending to crystallize.
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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
| | - Thomas Niemann
- Abteilung für Physikalische Chemie, Institut für Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany
| | - Peter Stange
- Abteilung für Physikalische Chemie, Institut für Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany
| | - 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
| | - 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
- Abteilung für Physikalische Chemie, Institut für Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, 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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48
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Inagaki M, Isogai T, Motobayashi K, Lin KQ, Ren B, Ikeda K. Electronic and vibrational surface-enhanced Raman scattering: from atomically defined Au(111) and (100) to roughened Au. Chem Sci 2020; 11:9807-9817. [PMID: 34094241 PMCID: PMC8162194 DOI: 10.1039/d0sc02976a] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In surface-enhanced Raman spectra, vibrational peaks are superimposed on a background continuum, which is known as one major experimental anomaly. This is problematic in assessing vibrational information especially in the low Raman-shift region below 200 cm−1, where the background signals dominate. Herein, we present a rigorous comparison of normal Raman and surface-enhanced Raman spectra for atomically defined surfaces of Au(111) or Au(100) with and without molecular adsorbates. It is clearly shown that the origin of the background continuum is well explained by a local field enhancement of electronic Raman scattering in the conduction band of Au. In the low Raman-shift region, electronic Raman scattering gains additional intensity, probably due to a relaxation in the conservation of momentum rule through momentum transfer from surface roughness. Based on the mechanism for generation of the spectral background, we also present a practical method to extract electronic and vibrational information at the metal/dielectric interface from the measured raw spectra by reducing the thermal factor, the scattering efficiency factor and the Purcell factor over wide ranges in both the Stokes and the anti-Stokes branches. This method enables us not only to analyse concealed vibrational features in the low Raman-shift region but also to estimate more reliable local temperatures from surface-enhanced Raman spectra. Both electronic and vibrational information at the metal/dielectric interface were explicitly extracted from surface-enhanced Raman spectra.![]()
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Affiliation(s)
- Motoharu Inagaki
- Department of Physical Science and Engineering, Nagoya Institute of Technology Gokiso, Showa Nagoya 466-8555 Japan
| | - Taichi Isogai
- Department of Physical Science and Engineering, Nagoya Institute of Technology Gokiso, Showa Nagoya 466-8555 Japan
| | - Kenta Motobayashi
- Department of Physical Science and Engineering, Nagoya Institute of Technology Gokiso, Showa Nagoya 466-8555 Japan
| | - Kai-Qiang Lin
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg Regensburg Germany
| | - Bin Ren
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University Xiamen 361005 China
| | - Katsuyoshi Ikeda
- Department of Physical Science and Engineering, Nagoya Institute of Technology Gokiso, Showa Nagoya 466-8555 Japan .,Frontier Research Institute for Materials Science (FRIMS), Nagoya Institute of Technology Gokiso, Showa Nagoya 466-8555 Japan
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49
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Photophysics and rotational dynamics of Nile red in room temperature ionic liquid (RTIL) and RTIL-cosolvents binary mixtures. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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50
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Wang YL, Li B, Sarman S, Mocci F, Lu ZY, Yuan J, Laaksonen A, Fayer MD. Microstructural and Dynamical Heterogeneities in Ionic Liquids. Chem Rev 2020; 120:5798-5877. [PMID: 32292036 PMCID: PMC7349628 DOI: 10.1021/acs.chemrev.9b00693] [Citation(s) in RCA: 197] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Indexed: 12/11/2022]
Abstract
Ionic liquids (ILs) are a special category of molten salts solely composed of ions with varied molecular symmetry and charge delocalization. The versatility in combining varied cation-anion moieties and in functionalizing ions with different atoms and molecular groups contributes to their peculiar interactions ranging from weak isotropic associations to strong, specific, and anisotropic forces. A delicate interplay among intra- and intermolecular interactions facilitates the formation of heterogeneous microstructures and liquid morphologies, which further contributes to their striking dynamical properties. Microstructural and dynamical heterogeneities of ILs lead to their multifaceted properties described by an inherent designer feature, which makes ILs important candidates for novel solvents, electrolytes, and functional materials in academia and industrial applications. Due to a massive number of combinations of ion pairs with ion species having distinct molecular structures and IL mixtures containing varied molecular solvents, a comprehensive understanding of their hierarchical structural and dynamical quantities is of great significance for a rational selection of ILs with appropriate properties and thereafter advancing their macroscopic functionalities in applications. In this review, we comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.
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Affiliation(s)
- Yong-Lei Wang
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Bin Li
- School
of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, P. R. China
| | - Sten Sarman
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Francesca Mocci
- Department
of Chemical and Geological Sciences, University
of Cagliari, I-09042 Monserrato, Italy
| | - Zhong-Yuan Lu
- State
Key Laboratory of Supramolecular Structure and Materials, Institute
of Theoretical Chemistry, Jilin University, Changchun 130021, P. R. China
| | - Jiayin Yuan
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Aatto Laaksonen
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
- State
Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China
- Centre of
Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry Aleea Grigore Ghica-Voda, 41A, 700487 Iasi, Romania
- Department
of Engineering Sciences and Mathematics, Division of Energy Science, Luleå University of Technology, SE-97187 Luleå, Sweden
| | - Michael D. Fayer
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
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