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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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2
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Hunger L, Ludwig R, Chuang YC, Chang HC. Hydroxy-Functionalized Ionic Liquids under Pressure: The Influence on Hydrogen Bonding between Ions of Opposite and Like Charges. J Phys Chem B 2024. [PMID: 38696327 DOI: 10.1021/acs.jpcb.4c01520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2024]
Abstract
Hydroxy functionalization of cations in ionic liquids (ILs) can lead to formation of hydrogen bonds between their OH groups, resulting in so-called (c-c) H-bonds. Thereby, the (c-c) H-bonds compete with regular H-bonds (c-a) between the OH groups and the anions. Polarizable cations, weakly interacting anions, and long alkyl chains at the cation support the propensity for the formation of (c-c) H-bonds. At low temperatures, the equilibrium between (c-c) and (c-a) H-bonds is strongly shifted in favor of the cation-cation interaction. Herein, we clarify the pressure dependence on (c-c) and (c-a) H-bond distributions in the IL 1-(2-hydroxyethyl)-3-methylimidazolium hexafluorophosphate [HOC2C1Im][PF6], in mixtures of [HOC2C1Im][PF6] with the nonhydroxy-functionalized IL 1-propyl-3-methylimidazolium hexafluorophosphate [C3C1Im][PF6] and in [HOC2C1Im][PF6] including trace amounts of water. The infrared (IR) spectra provide clear evidence that the (c-c) H-bonds diminish with increasing pressure in favor of the (c-a) H-bonds. Adding trace amounts of water results in enhanced (c-c) clustering due to cooperative effects. At ambient pressure, the water molecules are involved in the (c-c) H-bond motifs. Increasing pressure leads to squeezing them out of H-bond clusters, finally resulting in demixing of water and the IL at the microscopic level.
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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
| | - 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
| | - Yen-Ching Chuang
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Hai-Chou Chang
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
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3
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Khudozhitkov AE, Stepanov AG, Kolokolov DI, Ludwig R. Ion Mobility in Hydroxy-Functionalized Ionic Liquids Depends on Cationic Clustering: Tracking the Alkyl Chain Length Behavior with Deuteron NMR Relaxation. J Phys Chem B 2023; 127:9336-9345. [PMID: 37857325 DOI: 10.1021/acs.jpcb.3c05330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Observing and quantifying the like-charge attraction in liquids and solutions is still challenging. However, we showed that elusive cation-cation hydrogen bonding may govern the structure and interaction in hydroxyl-functionalized ionic liquids. Therefore, cationic cluster formation depends on the shape, charge distribution, and functionality of the ions. We demonstrated by means of solid-state 2H NMR spectroscopy that cationic clusters change the structure and dynamics of ionic liquids. With increasing alkyl chain length, we observed two deuteron quadrupole coupling constants for the OD groups, differing by about 30 kHz. The lower value was assigned to the cation-cation interaction, indicating that the average (c-c) hydrogen bonds are stronger than the (c-a) hydrogen bonds between the cation and the anion despite the repulsive and attractive Coulomb interaction in the first and latter cases. Ion mobility could be studied by 2H NMR spectroscopy, although the deuterons in the hydrogen-bonded clusters underwent fast exchange. Our results also showed that simple relaxation models are not applicable anymore and that anisotropic motion must be considered.
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Affiliation(s)
- Alexander E Khudozhitkov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
| | - Alexander G Stepanov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia
| | - Daniil I Kolokolov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
| | - Ralf Ludwig
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Albert-Einstein-Str. 27, 18059 Rostock, Germany
- Department LL&M, University of Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany
- Leibniz-Institut für Katalyse an der Universität Rostock e.V., Albert-Einstein-Str. 29a, 18059 Rostock, Germany
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4
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Bo Z, Zhang X, Huang Z, Huang Y, Yan J, Cen K, Yang H. Binary ionic liquids hybrid electrolyte based supercapacitors with high energy & power density. RSC Adv 2023; 13:15762-15771. [PMID: 37235105 PMCID: PMC10206612 DOI: 10.1039/d3ra01634j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Supercapacitors with high energy and power densities have become highly desirable in practical applications. Ionic liquids (ILs) are considered as promising electrolytes of supercapacitors owing to their excellent electrochemical stability window (approx. 4-6 V) and good thermal stability. However, the high viscosity (up to 102 mPa s) and low electric conductivity (<10 mS cm-1) at room-temperature extremely reduce the ion diffusion dynamics in the energy storage process, resulting in the unsatisfactory power density and rate performance of supercapacitors. Herein we propose a novel binary ionic liquids (BILs) hybrid electrolyte composed of two kinds of ILs in an organic solvent. Along with the organic solvent with high dielectric constant and low viscosity, the addition of binary cations effectively improves the electric conductivity and reduces the viscosity of IL electrolytes. By mixing trimethyl propylammonium bis(trifluoromethanesulfonyl)imide ([TMPA][TFSI]) and N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([Pyr14][TFSI]) with an equal mole ratio in acetonitrile (1 M), the as-prepared BILs electrolyte shows superior electric conductivity (44.3 mS cm-1), low viscosity (0.692 mPa s), and a wide electrochemical stability window (4.82 V). The supercapacitors assembled with activated carbon electrodes (commercial mass loading) and this BILs electrolyte achieve a high working voltage of 3.1 V, leading to a maximum energy density of 28.3 W h kg-1 at 803.35 W kg-1 and a maximum power density of 32.16 kW kg-1 at 21.17 W h kg-1, which are obviously superior to those of commercial supercapacitors based on organic electrolytes (2.7 V).
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Affiliation(s)
- Zheng Bo
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, College of Energy Engineering, Zhejiang University Hangzhou 310027 Zhejiang China
| | - Xu Zhang
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, College of Energy Engineering, Zhejiang University Hangzhou 310027 Zhejiang China
| | - Zhesong Huang
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, College of Energy Engineering, Zhejiang University Hangzhou 310027 Zhejiang China
| | - Yuhui Huang
- College of Materials Science and Engineering, Zhejiang University Hangzhou 310027 Zhejiang China
- Research Institute of Zhejiang University-Taizhou Taizhou Zhejiang Province 318000 China
| | - Jianhua Yan
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, College of Energy Engineering, Zhejiang University Hangzhou 310027 Zhejiang China
| | - Kefa Cen
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, College of Energy Engineering, Zhejiang University Hangzhou 310027 Zhejiang China
| | - Huachao Yang
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, College of Energy Engineering, Zhejiang University Hangzhou 310027 Zhejiang China
- Research Institute of Zhejiang University-Taizhou Taizhou Zhejiang Province 318000 China
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5
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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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6
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Assessing the impact of increase in the number of hydroxyl groups on the microscopic behaviors of ammonium-based room temperature ionic liquids: A combined fluorescence up-conversion, fluorescence correlation and NMR spectroscopic study. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2022.114505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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7
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Zhou G, Jiang K. Formation and Structure of Nanotubes in Imidazolium-Based Ionic Liquid Aqueous Solution. ACS OMEGA 2022; 7:45598-45608. [PMID: 36530223 PMCID: PMC9753178 DOI: 10.1021/acsomega.2c06381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 11/15/2022] [Indexed: 06/17/2023]
Abstract
Self-assembled structures have attracted much attention for their potential applications in biological and electrochemical studies. Understanding the aggregation mechanism is necessary for utilizing the structures and improving the properties. In this study, the tubular cluster aggregations formed by the 1-dodecyl-3-methylimidazolium salicylate ([C12mim][Sal]) have been studied by molecular dynamics simulations. The rod-like and funnel-shaped structures were observed during the simulations, and finally, the nanotube structure enclosed by a bilayer membrane was formed. For the first time, the point cloud fitting method was used to obtain the axis equation of the tubular cluster. Based on the equation, the structure of tubular clusters was analyzed in detail. The imidazolium ring and anions were distributed at the ionic liquid-water interface, while the dodecyl groups were buried in the nanotube membrane away from the water. Electrostatic interactions between cations and anions played a dominant role in stabilizing the structure of the nanotube. The tubular cluster size, membrane thickness, and permeability of water molecules through the membrane of the cluster were also calculated. Furthermore, the orientation analysis revealed that multitudinous aggregation structures could be formed by the long alkyl chain in aqueous solution, which might be beneficial for the strengthening and separating processes.
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Affiliation(s)
- Guohui Zhou
- School
of Chemistry and Chemical Engineering, Qingdao
University, Qingdao, Shandong 266071, China
| | - Kun Jiang
- Qingdao
University, Qingdao, Shandong 266071, China
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8
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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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9
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Computational approaches to structural properties investigation of triethylammonium- and triethanolammonium-based protic ionic liquids. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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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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11
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Bodo E. Perspectives in the Computational Modeling of New Generation, Biocompatible Ionic Liquids. J Phys Chem B 2022; 126:3-13. [PMID: 34978449 PMCID: PMC8762658 DOI: 10.1021/acs.jpcb.1c09476] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/15/2021] [Indexed: 12/11/2022]
Abstract
In this Perspective, I review the current state of computational simulations on ionic liquids with an emphasis on the recent biocompatible variants. These materials are used here as an example of relatively complex systems that highlights the limits of some of the approaches commonly used to study their structure and dynamics. The source of these limits consists of the coexistence of nontrivial electrostatic, many-body quantum effects, strong hydrogen bonds, and chemical processes affecting the mutual protonation state of the constituent molecular ions. I also provide examples on how it is possible to overcome these problems using suitable simulation paradigms and recently improved techniques that, I expect, will be gradually introduced in the state-of-the-art of computational simulations of ionic liquids.
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Affiliation(s)
- Enrico Bodo
- Chemistry Department, University of Rome “La Sapienza”, P. A. Moro 5, 00185 Rome, Italy
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12
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Al-Sheakh L, Fritsch S, Appelhagen A, Villinger A, Ludwig R. Thermodynamically Stable Cationic Dimers in Carboxyl-Functionalized Ionic Liquids: The Paradoxical Case of "Anti-Electrostatic" Hydrogen Bonding. Molecules 2022; 27:molecules27020366. [PMID: 35056680 PMCID: PMC8778807 DOI: 10.3390/molecules27020366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/28/2021] [Accepted: 01/03/2022] [Indexed: 11/18/2022] Open
Abstract
We show that carboxyl-functionalized ionic liquids (ILs) form doubly hydrogen-bonded cationic dimers (c+=c+) despite the repulsive forces between ions of like charge and competing hydrogen bonds between cation and anion (c+–a−). This structural motif as known for formic acid, the archetype of double hydrogen bridges, is present in the solid state of the IL 1−(carboxymethyl)pyridinium bis(trifluoromethylsulfonyl)imide [HOOC−CH2−py][NTf2]. By means of quantum chemical calculations, we explored different hydrogen-bonded isomers of neutral (HOOC–(CH2)n–py+)2(NTf2−)2, single-charged (HOOC–(CH2)n–py+)2(NTf2−), and double-charged (HOOC– (CH2)n−py+)2 complexes for demonstrating the paradoxical case of “anti-electrostatic” hydrogen bonding (AEHB) between ions of like charge. For the pure doubly hydrogen-bonded cationic dimers (HOOC– (CH2)n−py+)2, we report robust kinetic stability for n = 1–4. At n = 5, hydrogen bonding and dispersion fully compensate for the repulsive Coulomb forces between the cations, allowing for the quantification of the two equivalent hydrogen bonds and dispersion interaction in the order of 58.5 and 11 kJmol−1, respectively. For n = 6–8, we calculated negative free energies for temperatures below 47, 80, and 114 K, respectively. Quantum cluster equilibrium (QCE) theory predicts the equilibria between cationic monomers and dimers by considering the intermolecular interaction between the species, leading to thermodynamic stability at even higher temperatures. We rationalize the H-bond characteristics of the cationic dimers by the natural bond orbital (NBO) approach, emphasizing the strong correlation between NBO-based and spectroscopic descriptors, such as NMR chemical shifts and vibrational frequencies.
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Affiliation(s)
- Loai Al-Sheakh
- Institut für Chemie, Abteilung für Physikalische Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany; (L.A.-S.); (S.F.); (A.A.)
| | - Sebastian Fritsch
- Institut für Chemie, Abteilung für Physikalische Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany; (L.A.-S.); (S.F.); (A.A.)
| | - Andreas Appelhagen
- Institut für Chemie, Abteilung für Physikalische Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany; (L.A.-S.); (S.F.); (A.A.)
| | - Alexander Villinger
- Institut für Chemie, Abteilung für Anorganische Chemie, Universität Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany;
| | - Ralf Ludwig
- Institut für Chemie, Abteilung für Physikalische Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany; (L.A.-S.); (S.F.); (A.A.)
- 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
- Correspondence:
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13
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Ludwig R. Towards thermodynamically stable anionic dimers with “anti-electrostatic” hydrogen bonds overcoming like-charge repulsion. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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14
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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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15
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Wang TH, Wang WX, Chang HC. Pressure-Dependent Clustering in Ionic-Liquid-Poly (Vinylidene Fluoride) Mixtures: An Infrared Spectroscopic Study. NANOMATERIALS 2021; 11:nano11082099. [PMID: 34443929 PMCID: PMC8400791 DOI: 10.3390/nano11082099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/11/2021] [Accepted: 08/17/2021] [Indexed: 12/03/2022]
Abstract
The nanostructures of ionic liquids (ILs) have been the focus of considerable research attention in recent years. Nevertheless, the nanoscale structures of ILs in the presence of polymers have not been described in detail at present. In this study, nanostructures of ILs disturbed by poly(vinylidene fluoride) (PVdF) were investigated via high-pressure infrared spectra. For 1-(2-hydroxyethyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([HEMIm][TFSI])-PVdF mixtures, non-monotonic frequency shifts of the C4,5-H vibrations upon dilution were observed under ambient pressure. The experimental results suggest the presence of microheterogeneity in the [HEMIm][TFSI] systems. Upon compression, PVdF further influenced the local structure of C4,5–H via pressure-enhanced IL–PVdF interactions; however, the local structures of C2–H and hydrogen-bonded O–H were not affected by PVdF under high pressures. For choline [TFSI]–PVdF mixtures, PVdF may disturb the local structures of hydrogen-bonded O–H. In the absence of the C4,5–H⋯anion and C2–H⋯anion in choline [TFSI]–PVdF mixtures, the O–H group becomes a favorable moiety for pressure-enhanced IL–PVdF interactions. Our results indicate the potential of high-pressure application for designing pressure-dependent electronic switches based on the possible changes in the microheterogeneity and electrical conductivity in IL-PVdF systems under various pressures.
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Affiliation(s)
| | | | - Hai-Chou Chang
- Correspondence: ; Tel.: +886-3-8903585; Fax: +886-3-8900162
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16
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Javed MN, Ali Hashmi I, Muhammad S, Bari A, Ghulam Musharraf S, Junaid Mahmood S, Javed S, Imran Ali F, Rafique F, Amjad Ilyas M, Ahmed Waseem W. Ionic liquids containing plant derived benzoate as anions, exhibiting supramolecular polymeric aggregation: Impact of the aggregation on organic catalysis in aqueous medium. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116329] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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17
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18
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Neumann J, Ludwig R, Paschek D. Hydrogen Bonds between Ions of Opposite and Like Charge in Hydroxyl-Functionalized Ionic Liquids: an Exhaustive Examination of the Interplay between Global and Local Motions and Intermolecular Hydrogen Bond Lifetimes and Kinetics. J Phys Chem B 2021; 125:5132-5144. [PMID: 33971719 DOI: 10.1021/acs.jpcb.1c02756] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hydroxyl-functionalized ionic liquids (ILs) represent a new interesting class of ILs where hydrogen bonds (HBs) play an important role: here, "typical" HBs between cations and anions (ca) are competing with "atypical" HBs connecting pairs of cations (cc). We study the equilibrium and kinetics of (cc) and (ca) HBs in 1-(n-hydroxyalkyl)-pyridinium bis(trifluoromethlysulfonyl)imide [HOCnPy][NTf2] ILs by means of molecular dynamics simulations. (cc) HBs are found to be between 0.96 and 3.76 kJ mol-1 stronger than their (ca) counterparts, depending on the alkyl chain length. HB lifetimes and kinetics are analyzed by means of HB population and reactive flux correlation functions. Essentially, four different HB lifetimes have to be considered, spanning about 3 orders of magnitude, each valid in its own right and each associated with different aspects of HB breaking and HB reformation. The long-time limiting behavior of the HB population correlation function is controlled by diffusion of the ions and can be quantitatively described by analytical expressions. The short-time HB behavior is tied to the localized dynamics of the hydroxyl group exploring its local solvation environment. A minimalist kinetic two-domain model is introduced to realistically describe the time evolution of the HB population correlation function for both (ca) and (cc) HBs over 5 orders of magnitude. By employing the reactive flux method, we determine the kinetics of HB breaking, unaffected by diffusion processes. We determine both, the ultrafast upper boundary and the average rate of HB breaking, allowing recrossing-events during the transient relaxation time period. For sufficiently long alkyl chains, all those computed HB lifetimes indicate a higher kinetic stability of (cc) HBs over (ca) HBs; for short chains, it is vice-versa.
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Affiliation(s)
- Jan Neumann
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Str. 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.,Department Life, Light & Matter, Universität Rostock, Albert-Einstein-Str. 25, D-18059 Rostock, Germany.,Leibniz Institut für Katalyse an der Universität Rostock, Albert-Einstein-Str. 29a, D-18059 Rostock, Germany
| | - Dietmar Paschek
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Str. 21, D-18059 Rostock, Germany
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19
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Bodo E. Modelling biocompatible ionic liquids based on organic acids and amino acids: challenges for computational models and future perspectives. Org Biomol Chem 2021; 19:4002-4013. [PMID: 33978045 DOI: 10.1039/d1ob00011j] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this short review I shall highlight the basic principle and the difficulties that arise in attempting the computational modeling of seemingly simple systems which hide an unexpected complexity. Biocompatible ionic liquids which are based on the coupling of organic or amino acid anions with metabolic cations such as cholinium are the target of this review. These substances have been the subject of intense research activities in the last few years and have attracted the attention of computational chemists. I shall show that the computational description of these substances is far from trivial and requires the use of sophisticated techniques in order to account for a surprisingly rich chemistry that is due to several phenomena such as polarization, charge transfer, proton transfer equilibria and tautomerization reactions.
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Affiliation(s)
- Enrico Bodo
- Chemistry Department, University of Rome "La Sapienza", P. A. Moro 5, 00185 Rome, Italy.
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20
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Assenine MA, Haddad B, Paolone A, Brandán SA, Goussem M, Villemin D, Boumediene M, Rahmouni M, Bresson S. Synthesis, thermal properties, vibrational spectra and computational studies of Trioctylmethylammonium bis(trifluoromethylsulfonyl)imide ionic liquid. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130085] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Assenine MA, Haddad B, Paolone A, Brandán SA, Villemin D, Boumediene M, Rahmouni M, Bresson S. Experimental and DFT studies on structure, spectroscopic and thermal properties of N-Methyl-N,N,N-trioctylammonium chloride ionic liquid. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2020.129625] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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22
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Chen J, Dong K, Liu L, Zhang X, Zhang S. Anti-electrostatic hydrogen bonding between anions of ionic liquids: a density functional theory study. Phys Chem Chem Phys 2021; 23:7426-7433. [PMID: 33876102 DOI: 10.1039/d0cp06718k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrogen bonds (HBs) play a crucial role in the physicochemical properties of ionic liquids (ILs). To date, HBs between cations and anions (Ca-An) or between cations (Ca-Ca) in ILs have been reported extensively. Here, we provided DFT evidence for the existence of HBs between anions (An-An) in the IL 1-(2-hydroxyethyl)-3-methylimidazolium 4-(2-hydroxyethyl)imidazolide [HEMIm][HEIm]. The thermodynamic stabilities of anionic, cationic, and H2O dimers together with ionic pairs were studied using potential energy scans. The results show that the cation-anion pair is the most stable one, while the HB in the anionic dimer possesses similar thermodynamic stability to the water dimer. The further geometric, spectral and electronic structure analyses demonstrate that the inter-anionic HB meets the general theoretical criteria of traditional HBs. The strength order of four HBs in complexes is cation-anion pair > H2O dimer ≈ cationic dimer > anionic dimer. The energy decomposition analysis indicates that induction and dispersion interactions are the crucial factors to overcome strong Coulomb repulsions, forming inter-anionic HBs. Finally, the presence of inter-anionic HBs in the ionic cluster has been confirmed by a global minimum search for a system containing two ionic pairs. Even though hydroxyl-functionalized cations are more likely to form HBs with anions, there are still inter-anionic HBs between hydroxyl groups in the low-lying structures. Our studies broaden the understanding of HBs in ionic liquids and support the recently proposed concept of anti-electrostatic HBs.
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Affiliation(s)
- Junwu Chen
- Beijing Key Laboratory of Ionic Liquids Clean Process, CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China.
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23
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Neumann J, Paschek D, Strate A, Ludwig R. Kinetics of Hydrogen Bonding between Ions with Opposite and Like Charges in Hydroxyl-Functionalized Ionic Liquids. J Phys Chem B 2021; 125:281-286. [PMID: 33356283 DOI: 10.1021/acs.jpcb.0c09278] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hydrogen-bonded structures and their lifetimes in ionic liquids (ILs) are governed by the subtle balance between Coulomb interactions, hydrogen bonding, and dispersion forces. Despite the dominant Coulomb interaction, local and directional hydrogen bonds (HBs) can play an important role in the behavior of ILs. Compared to water, the archetype of hydrogen-bonded liquids, ILs have larger constituents and higher viscosities but are typically lacking a three-dimensional HB network. Hydroxyl-functionalized ionic liquids are even more special: regular HBs between cations and anions (ca) are accompanied by HBs between pairs of cations (cc). Recently, infrared (IR) measurements have suggested that the (cc) HBs are even stronger than their (ca) counterparts and their strength can be controlled via the hydroxyalkyl chain length. In this paper, we show by means of molecular dynamics (MD) simulations that the presence of HBs has a profound effect on the molecular mobility of the ions. We investigate the kinetic mechanism of hydrogen bonding in ILs and show that the lifetimes and hence the stability of (cc) HBs increase with the chain length, making them more stable than the respective (ca) HBs. The observed HB equilibrium can explain the peculiar chain length dependence of the relative molecular mobilities of the ions by a direct comparison between hydroxyl-functionalized ILs with their nonfunctionalized counterparts.
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Affiliation(s)
- Jan Neumann
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, D-18059 Rostock, Germany
| | - Dietmar Paschek
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, D-18059 Rostock, Germany
| | - Anne Strate
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, D-18059 Rostock, Germany.,Department Life, Light & Matter, Universität Rostock, Albert-Einstein-Straße 25, D-18059 Rostock, Germany
| | - Ralf Ludwig
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Dr.-Lorenz-Weg 2, D-18059 Rostock, Germany.,Department Life, Light & Matter, Universität Rostock, Albert-Einstein-Straße 25, D-18059 Rostock, Germany.,Leibniz Institut für Katalyse an der Universität Rostock, Albert-Einstein-Straße 29a, D-18059 Rostock, Germany
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24
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Le Donne A, Bodo E. Cholinium amino acid-based ionic liquids. Biophys Rev 2021; 13:147-160. [PMID: 33747249 PMCID: PMC7930144 DOI: 10.1007/s12551-021-00782-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/05/2021] [Indexed: 12/12/2022] Open
Abstract
Boosted by the simplicity of their synthesis and low toxicity, cholinium and amino acid-based ionic liquids have attracted the attention of researchers in many different fields ranging from computational chemistry to electrochemistry and medicine. Among the uncountable IL variations, these substances occupy a space on their own due to their exceptional biocompatibility that stems from being entirely made by metabolic molecular components. These substances have undergone a rather intensive research activity because of the possibility of using them as greener replacements for traditional ionic liquids. We present here a short review in the attempt to provide a compendium of the state-of-the-art scientific research about this special class of ionic liquids based on the combination of amino acid anions and cholinium cations.
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Affiliation(s)
- Andrea Le Donne
- Chemistry Department, University of Rome "La Sapienza", Piazzale A. Moro 5, 00185 Rome, Italy
| | - Enrico Bodo
- Chemistry Department, University of Rome "La Sapienza", Piazzale A. Moro 5, 00185 Rome, Italy
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25
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Wysokiński R, Zierkiewicz W, Michalczyk M, Scheiner S. Anionanion (MX 3-) 2 dimers (M = Zn, Cd, Hg; X = Cl, Br, I) in different environments. Phys Chem Chem Phys 2021; 23:13853-13861. [PMID: 34156052 DOI: 10.1039/d1cp01502h] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The possibility that MX3- anions can interact with one another is assessed via ab initio calculations in gas phase as well as in aqueous and ethanol solution. A pair of such anions can engage in two different dimer types. In the bridged configuration, two X atoms engage with two M atoms in a rhomboid structure with four equal M-X bond lengths. The two monomers retain their identity in the stacked geometry which contains a pair of noncovalent MX interactions. The relative stabilities of these two structures depend on the nature of the central M atom, the halogen substituent, and the presence of solvent. The interaction and binding energies are fairly small, generally no more than 10 kcal mol-1. The large electrostatic repulsion is balanced by a strong attractive polarization energy.
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Affiliation(s)
- Rafał Wysokiński
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
| | - Wiktor Zierkiewicz
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
| | - Mariusz Michalczyk
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
| | - Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University Logan, Utah 84322-0300, USA.
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26
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Thomann CA, Münzner P, Moch K, Jacquemin J, Goodrich P, Sokolov AP, Böhmer R, Gainaru C. Tuning the dynamics of imidazolium-based ionic liquids via hydrogen bonding. I. The viscous regime. J Chem Phys 2020; 153:194501. [DOI: 10.1063/5.0026144] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- C. A. Thomann
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - P. Münzner
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - K. Moch
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - J. Jacquemin
- Faculté des Sciences et Techniques, Université de Tours, 37200 Tours, France
- QUILL Center, The Queen’s University of Belfast, Belfast BT9 5AG, Northern Ireland, United Kingdom
| | - P. Goodrich
- QUILL Center, The Queen’s University of Belfast, Belfast BT9 5AG, Northern Ireland, United Kingdom
| | - A. P. Sokolov
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37916, USA and Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - R. Böhmer
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - C. Gainaru
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
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27
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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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28
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Synthesis and characterization of bio-based quaternary ammonium salts with gibberellate or l-tryptophanate anion. MONATSHEFTE FUR CHEMIE 2020. [DOI: 10.1007/s00706-020-02672-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
AbstractNumerous biologically active acids can be transformed into an ionic form in a facile way and combined with appropriate quaternary ammonium cation to improve their application properties or biological activity. This study describes the synthesis of new quaternary ammonium salts with anions of gibberellic acid, a common plant growth regulator from the gibberellin group, or l-tryptophan, an important precursor of auxin biosynthesis. The surface-active tetrapentylammonium ion and natural substances such as acetylcholine, choline, and quinine were the sources of cations. Novel salts of gibberellic acid and l-tryptophan were obtained with high yields exceeding 97% as a result of the metathesis reaction or the neutralization of quaternary ammonium hydroxides. Phase transition temperatures, thermal and chemical stability, and solubility in solvents with different polarities were determined for all obtained salts. On the basis of studies regarding the influence of synthesized salts on the post-harvest longevity and quality of leaves of Convallaria majalis, it was established that the biological activity of the natural plant regulators in most cases was maintained. Therefore, it can be concluded that the conversion of the active substance into the form of a quaternary ammonium salt results in obtaining novel forms of plant growth regulators with favourable physicochemical properties while maintaining the efficacy of the biological active ingredients.
Graphic abstract
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29
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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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30
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Bader K, Müller C, Molard Y, Baro A, Ehni P, Knelles J, Laschat S. Fluorenone imidazolium salts as novel de Vries materials. RSC Adv 2020; 10:23999-24016. [PMID: 35517358 PMCID: PMC9055108 DOI: 10.1039/d0ra04650g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 06/15/2020] [Indexed: 01/09/2023] Open
Abstract
In ionic liquid crystals (ILCs) tilted mesophases such as SmC required for electro-optic devices are quite rare. We report a design concept that induced the SmC phase and enabled de Vries-like behaviour in ILCs. For this purpose, we synthesized and characterized a library of ILC derivatives ImR(On,Ym)X which consist of a rigid central fluorenone core containing an alkoxy or thioether side chain and connected via a flexible spacer to an imidazolium head group. The mesomorphic properties were studied by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD). Temperature-dependent measurements of smectic layer spacing d by small-angle X-ray scattering (SAXS) and of optical tilt angles by POM demonstrate that ILCs ImR(On,Ym)X undergo SmA–SmC phase transitions with maximum layer contraction values between 0.4% and 2.1%. The lowest reduction factor R of 0.2 at the reduced temperature T − TAC = −10 K was calculated for Im(O12,S14)Br. Electron density calculations indicated a bilayer structure. Furthermore, temperature dependent emission studies show that self-assembling has a strong influence on the emission intensity of these ILCs. ILCs consisting of cationic head group–spacer–fluorenone central core–side chain show de Vries-like behaviour.![]()
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Affiliation(s)
- Korinna Bader
- Institut für Organische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Carsten Müller
- Institut für Physikalische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Yann Molard
- CNRS, ISCR-UMR 6226, ScanMAT-UMS 2001, University Rennes 35000 Rennes France
| | - Angelika Baro
- Institut für Organische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Philipp Ehni
- Institut für Organische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Jakob Knelles
- Institut für Organische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Sabine Laschat
- Institut für Organische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
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31
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Li H, Niemann T, Ludwig R, Atkin R. Effect of Hydrogen Bonding between Ions of Like Charge on the Boundary Layer Friction of Hydroxy-Functionalized Ionic Liquids. J Phys Chem Lett 2020; 11:3905-3910. [PMID: 32338913 DOI: 10.1021/acs.jpclett.0c00689] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Atomic force microscopy has been used to measure the lubricity of a series of ionic liquids (ILs) at mica surfaces in the boundary friction regime. A previously unreported cation bilayer structure is detected at the IL-mica interface due to the formation of H-bonds between the hydroxy-functionalized cations [(c-c) H-bonds], which enhances the ordering of the ions in the boundary layer and improves the lubrication. The strength of the cation bilayer structure is controlled by altering the strength of (c-c) H-bonding via changes in the hydroxyalkyl chain length, the cation charge polarizability, and the coordination strength of the anions. This reveals a new means of controlling IL boundary nanostructure via H-bonding between ions of the same charge, which can impact diverse applications, including surface catalysis, particle stability, electrochemistry, etc.
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Affiliation(s)
- Hua Li
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Thomas Niemann
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany
- Department LL&M, University of Rostock, Albert-Einstein-Strasse 25, 18059 Rostock, Germany
| | - Ralf Ludwig
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, 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
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia 6009, Australia
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32
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Zeng HJ, Menges FS, Niemann T, Strate A, Ludwig R, Johnson MA. Chain Length Dependence of Hydrogen Bond Linkages between Cationic Constituents in Hydroxy-Functionalized Ionic Liquids: Tracking Bulk Behavior to the Molecular Level with Cold Cluster Ion Spectroscopy. J Phys Chem Lett 2020; 11:683-688. [PMID: 31899639 DOI: 10.1021/acs.jpclett.9b03359] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Hydroxy functionalization of cations in ionic liquids (ILs) can lead to formation of contacts between their OH groups [so-called (c-c) interactions]. One class of these linkages involves cooperatively enhanced hydrogen bonds to anionic partners that are sufficiently strong to overcome the repulsion between two positively charged centers. Herein, we clarify how the propensity for the formation of (c-c) contacts depends on the alkyl chain length between two cationic rings and their OH groups by analyzing the temperature-dependent IR spectra of bulk ILs as well as the vibrational predissociation spectra of ∼35 K complexes comprised of two cations and one anion. This study compares the behavior of two cationic derivatives with ethyl and propyl chains complexed with two different anions: bis(trifluoromethylsulfonyl)imide and tetrafluoroborate. Only the bulk ILs with the longer chain propyl derivative [HPMPip+ = 1-(3-hydroxypropyl)-1-methylpiperidinium] display (c-c) interactions. Molecular-level aspects of this docking arrangement are revealed by analyzing the OH stretching fundamentals displayed by the ternary complexes.
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Affiliation(s)
- Helen J Zeng
- Sterling Chemistry Laboratory , Yale University , New Haven , Connecticut 06520 , United States
| | - Fabian S Menges
- Sterling Chemistry Laboratory , Yale University , New Haven , Connecticut 06520 , United States
| | - Thomas Niemann
- Department of Chemistry , University of Rostock , 18059 Rostock , Germany
- Department Life, Light & Matter , University of Rostock , Albert-Einstein-Strasse 25 , 18059 Rostock , Germany
| | - Anne Strate
- Department of Chemistry , University of Rostock , 18059 Rostock , Germany
- Department Life, Light & Matter , University of Rostock , Albert-Einstein-Strasse 25 , 18059 Rostock , Germany
| | - Ralf Ludwig
- Department of Chemistry , University of Rostock , 18059 Rostock , Germany
- Department Life, Light & Matter , University of Rostock , Albert-Einstein-Strasse 25 , 18059 Rostock , Germany
- Leibniz-Institut für Katalyse e.V. , Albert-Einstein-Strasse 29a , 18059 Rostock , Germany
| | - Mark A Johnson
- Sterling Chemistry Laboratory , Yale University , New Haven , Connecticut 06520 , United States
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33
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Niemann T, Zaitsau DH, Strate A, Stange P, Ludwig R. Controlling "like-likes-like" charge attraction in hydroxy-functionalized ionic liquids by polarizability of the cations, interaction strength of the anions and varying alkyl chain length. Phys Chem Chem Phys 2020; 22:2763-2774. [PMID: 31951236 DOI: 10.1039/c9cp06481h] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We provide comprehensive understanding of "like-likes-like" charge attraction in hydroxy-functionalized ionic liquids (ILs) by means of infrared spectroscopy (IR), quantum chemistry and differential scanning calorimetry (DSC). We show that hydrogen bonding between cation and cation (c-c) is possible despite the repulsive forces between ions of like charge. Already at room temperature, the (c-c) hydrogen bonds can compete with the regular Coulomb-enhanced hydrogen bonds between cation and anion (c-a). For a large set of well-selected ILs, we show that "like-charge attraction" between the OH-functionalized cations is controllable by the polarizability of the cation, the interaction strength of the anion and the length of the hydroxyalkyl chain. In particular, we clarify whether tethering the OH group away from the positive charge center of the cationic ring with longer hydroxyalkyl chains compensates for unfavourable cation/anion combinations with respect to (c-c) cluster formation. For that purpose, we synthesized and characterized twelve ionic liquids including the differently polarizable cations, 1-(n-hydroxyalkyl)-1-methylpiperidinium [HOCnMPip]+ and 1-(n-hydroxyalkyl)-pyridinium [HOCnPy]+, as well as the weakly and strongly interacting anions, bis(trifluoromethanesulfonyl)imide [NTf2]- and methanesulfonate [OMs]-, respectively. On top, we varied the hydroxyalkyl chain length (HOCn) (n = 2-5). We systematically show how these three molecular ion parameters affect like-charge attraction. The use of polarizable cations, weakly interacting anions, and long alkyl chain tethers results in (c-c) clustering already at room temperature. Kinetic trapping is not a prerequisite for the existence of (c-c) cluster species in ILs. Moreover, we demonstrate that micro structuring affects macroscopic behavior of this type of ILs. We observed that substantial (c-c) interaction prevents ILs from crystallizing. Instead, these ILs supercool and finally form a glass.
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Affiliation(s)
- Thomas Niemann
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr-Lorenz-Weg 2, 18059, Rostock, Germany.
| | - Dzmitry H Zaitsau
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr-Lorenz-Weg 2, 18059, Rostock, Germany. and Department LL&M, University of Rostock, Albert-Einstein-Str. 25, 18059, Rostock, Germany
| | - Anne Strate
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr-Lorenz-Weg 2, 18059, Rostock, Germany. and Department LL&M, University of Rostock, Albert-Einstein-Str. 25, 18059, Rostock, Germany
| | - Peter Stange
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr-Lorenz-Weg 2, 18059, Rostock, Germany.
| | - Ralf Ludwig
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr-Lorenz-Weg 2, 18059, Rostock, Germany. and Department LL&M, University of Rostock, Albert-Einstein-Str. 25, 18059, Rostock, Germany and Leibniz-Institut für Katalyse an der Universität Rostock e.V., Albert-Einstein-Str. 29a, 18059 Rostock, Germany
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34
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Strate A, Neumann J, Niemann T, Stange P, Khudozhitkov AE, Stepanov AG, Paschek D, Kolokolov DI, Ludwig R. Counting cations involved in cationic clusters of hydroxy-functionalized ionic liquids by means of infrared and solid-state NMR spectroscopy. Phys Chem Chem Phys 2020; 22:6861-6867. [PMID: 32202267 DOI: 10.1039/d0cp00303d] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Sensitive probe of like-charge attraction: analyzing infrared spectra allows counting the number of cations involved in clusters of opposite (c–a) and like-charged (c–c) ions in ionic liquids. This approach is also applicable to molecular liquids.
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Affiliation(s)
- Anne Strate
- Universität Rostock
- Institut für Chemie
- Abteilung für Physikalische Chemie
- 18059 Rostock
- Germany
| | - Jan Neumann
- Universität Rostock
- Institut für Chemie
- Abteilung für Physikalische Chemie
- 18059 Rostock
- Germany
| | - Thomas Niemann
- Universität Rostock
- Institut für Chemie
- Abteilung für Physikalische Chemie
- 18059 Rostock
- Germany
| | - Peter Stange
- Universität Rostock
- Institut für Chemie
- Abteilung für Physikalische Chemie
- 18059 Rostock
- Germany
| | - Alexander E. Khudozhitkov
- Boreskov Institute of Catalysis
- Siberian Branch of Russian Academy of Sciences
- Novosibirsk 630090
- Russia
- Novosibirsk State University
| | - Alexander G. Stepanov
- Boreskov Institute of Catalysis
- Siberian Branch of Russian Academy of Sciences
- Novosibirsk 630090
- Russia
- Novosibirsk State University
| | - Dietmar Paschek
- Universität Rostock
- Institut für Chemie
- Abteilung für Physikalische Chemie
- 18059 Rostock
- Germany
| | - Daniil I. Kolokolov
- Boreskov Institute of Catalysis
- Siberian Branch of Russian Academy of Sciences
- Novosibirsk 630090
- Russia
- Novosibirsk State University
| | - Ralf Ludwig
- Universität Rostock
- Institut für Chemie
- Abteilung für Physikalische Chemie
- 18059 Rostock
- Germany
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35
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Rabideau BD, Soltani M, Parker RA, Siu B, Salter EA, Wierzbicki A, West KN, Davis JH. Tuning the melting point of selected ionic liquids through adjustment of the cation's dipole moment. Phys Chem Chem Phys 2020; 22:12301-12311. [PMID: 32432261 DOI: 10.1039/d0cp01214a] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In previous work with thermally robust salts [Cassity et al., Phys. Chem. Chem. Phys., 2017, 19, 31560] it was noted that an increase in the dipole moment of the cation generally led to a decrease in the melting point. Molecular dynamics simulations of the liquid state revealed that an increased dipole moment reduces cation-cation repulsions through dipole-dipole alignment. This was believed to reduce the liquid phase enthalpy, which would tend to lower the melting point of the IL. In this work we further test this principle by replacing hydrogen atoms with fluorine atoms at selected positions within the cation. This allows us to alter the electrostatics of the cation without substantially affecting the sterics. Furthermore, the strength of the dipole moment can be controlled by choosing different positions within the cation for replacement. We studied variants of four different parent cations paired with bistriflimide and determined their melting points, and enthalpies and entropies of fusion through DSC experiments. The decreases in the melting point were determined to be enthalpically driven. We found that the dipole moment of the cation, as determined by quantum chemical calculations, is inversely correlated with the melting point of the given compound. Molecular dynamics simulations of the crystalline and solid states of two isomers showed differences in their enthalpies of fusion that closely matched those seen experimentally. Moreover, this reduction in the enthalpy of fusion was determined to be caused by an increase in the enthalpy of the crystalline state. We provide evidence that dipole-dipole interactions between cations leads to the formation of cationic domains in the crystalline state. These cationic associations partially block favourable cation-anion interactions, which are recovered upon melting. If, however, the dipole-dipole interactions between cations is too strong they have a tendency to form glasses. This study provides a design rule for lowering the melting point of structurally similar ILs by altering their dipole moment.
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Affiliation(s)
- Brooks D Rabideau
- Department of Chemical & Biomolecular Engineering, The University of South Alabama, Mobile, Alabama 36688, USA.
| | - Mohammad Soltani
- Department of Chemistry, The University of South Alabama, Mobile, Alabama 36688, USA.
| | - Rome A Parker
- Department of Chemical & Biomolecular Engineering, The University of South Alabama, Mobile, Alabama 36688, USA.
| | - Benjamin Siu
- Department of Chemical & Biomolecular Engineering, The University of South Alabama, Mobile, Alabama 36688, USA.
| | - E Alan Salter
- Department of Chemistry, The University of South Alabama, Mobile, Alabama 36688, USA.
| | - Andrzej Wierzbicki
- Department of Chemistry, The University of South Alabama, Mobile, Alabama 36688, USA.
| | - Kevin N West
- Department of Chemical & Biomolecular Engineering, The University of South Alabama, Mobile, Alabama 36688, USA.
| | - James H Davis
- Department of Chemistry, The University of South Alabama, Mobile, Alabama 36688, USA.
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36
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Niemann T, Li H, Warr GG, Ludwig R, Atkin R. Influence of Hydrogen Bonding between Ions of Like Charge on the Ionic Liquid Interfacial Structure at a Mica Surface. J Phys Chem Lett 2019; 10:7368-7373. [PMID: 31713427 DOI: 10.1021/acs.jpclett.9b03007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ionic liquids (ILs) have attracted increasing interest in science and technology because of their remarkable properties, which can be tuned via varying ion structures to control the relative strengths of Coulomb interactions, hydrogen bonding (H-bonding), and dispersion forces. Here we use atomic force microscopy to probe the interfacial nanostructures of hydroxy functionalized ILs at negatively charged mica surfaces. H-bonding between hydroxy functionalized cations (c-c) produces cation clusters and a stronger interfacial nanostructure. H-bond stabilized cation clusters form despite opposing electrostatic repulsions between charge groups, cation-anion (c-a) electrostatic attractions, and (c-a) H-bonds. Comparison of ILs with and without OH functionalized cations shows directional H-bonding enhances interfacial structure more strongly than the dispersion forces between alkyl groups. These findings reveal a new means of controlling IL interfacial nanostructure via H-bonding between like-charged ions, which impact diverse areas including electrochemical charge storage (batteries and catalysis), electrodeposition, lubrication, etc.
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Affiliation(s)
- Thomas Niemann
- Institut für Chemie, Abteilung für Physikalische Chemie , Universität Rostock , Dr.-Lorenz-Weg 2 , 18059 Rostock , Germany
- Department LL&M , University of Rostock , Albert-Einstein-Str. 25 , 18059 Rostock , Germany
| | - Hua Li
- School of Molecular Sciences , The University of Western Australia , Perth , Western Australia 6009 , Australia
| | - Gregory G Warr
- School of Chemistry and Sydney Nano Institute , The University of Sydney , Camperdown , NSW 2006 , Australia
| | - Ralf Ludwig
- Institut für Chemie, Abteilung für Physikalische Chemie , Universität Rostock , Dr.-Lorenz-Weg 2 , 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
| | - Rob Atkin
- School of Molecular Sciences , The University of Western Australia , Perth , Western Australia 6009 , Australia
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37
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Khudozhitkov AE, Neumann J, Niemann T, Zaitsau D, Stange P, Paschek D, Stepanov AG, Kolokolov DI, Ludwig R. Hydrogen Bonding Between Ions of Like Charge in Ionic Liquids Characterized by NMR Deuteron Quadrupole Coupling Constants-Comparison with Salt Bridges and Molecular Systems. Angew Chem Int Ed Engl 2019; 58:17863-17871. [PMID: 31588622 PMCID: PMC6899581 DOI: 10.1002/anie.201912476] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Indexed: 11/23/2022]
Abstract
We present deuteron quadrupole coupling constants (DQCC) for hydroxyl-functionalized ionic liquids (ILs) in the crystalline or glassy states characterizing two types of hydrogen bonding: The regular Coulomb-enhanced hydrogen bonds between cation and anion (c-a), and the unusual hydrogen bonds between cation and cation (c-c), which are present despite repulsive Coulomb forces. We measure these sensitive probes of hydrogen bonding by means of solid-state NMR spectroscopy. The DQCCs of (c-a) ion pairs and (c-c) H-bonds are compared to those of salt bridges in supramolecular complexes and those present in molecular liquids. At low temperatures, the (c-c) species successfully compete with the (c-a) ion pairs and dominate the cluster populations. Equilibrium constants obtained from molecular-dynamics (MD) simulations show van't Hoff behavior with small transition enthalpies between the differently H-bonded species. We show that cationic-cluster formation prevents these ILs from crystallizing. With cooling, the (c-c) hydrogen bonds persist, resulting in supercooling and glass formation.
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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
| | - Jan Neumann
- Universität RostockInstitut für ChemieAbteilung für Physikalische ChemieDr.-Lorenz-Weg 218059RostockGermany
| | - Thomas Niemann
- Universität RostockInstitut für ChemieAbteilung für Physikalische ChemieDr.-Lorenz-Weg 218059RostockGermany
| | - Dzmitry Zaitsau
- Department LL&MUniversity of RostockAlbert-Einstein-Str. 2518059RostockGermany
| | - Peter Stange
- Universität RostockInstitut für ChemieAbteilung für Physikalische ChemieDr.-Lorenz-Weg 218059RostockGermany
| | - Dietmar Paschek
- Universität RostockInstitut für ChemieAbteilung für Physikalische ChemieDr.-Lorenz-Weg 218059RostockGermany
| | - Alexander G. Stepanov
- Boreskov Institute of CatalysisSiberian Branch of Russian Academy of SciencesProspekt Akademika Lavrentieva 5Novosibirsk630090Russia
- Novosibirsk State UniversityPirogova Street 2Novosibirsk630090Russia
| | - 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 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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38
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Khudozhitkov AE, Neumann J, Niemann T, Zaitsau D, Stange P, Paschek D, Stepanov AG, Kolokolov DI, Ludwig R. Hydrogen Bonding Between Ions of Like Charge in Ionic Liquids Characterized by NMR Deuteron Quadrupole Coupling Constants—Comparison with Salt Bridges and Molecular Systems. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201912476] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Alexander E. Khudozhitkov
- Boreskov Institute of CatalysisSiberian Branch of Russian Academy of Sciences Prospekt Akademika Lavrentieva 5 Novosibirsk 630090 Russia
- Novosibirsk State University Pirogova Street 2 Novosibirsk 630090 Russia
| | - Jan Neumann
- Universität RostockInstitut für ChemieAbteilung für Physikalische Chemie Dr.-Lorenz-Weg 2 18059 Rostock Germany
| | - Thomas Niemann
- Universität RostockInstitut für ChemieAbteilung für Physikalische Chemie Dr.-Lorenz-Weg 2 18059 Rostock Germany
| | - Dzmitry Zaitsau
- Department LL&MUniversity of Rostock Albert-Einstein-Str. 25 18059 Rostock Germany
| | - Peter Stange
- Universität RostockInstitut für ChemieAbteilung für Physikalische Chemie Dr.-Lorenz-Weg 2 18059 Rostock Germany
| | - Dietmar Paschek
- Universität RostockInstitut für ChemieAbteilung für Physikalische Chemie Dr.-Lorenz-Weg 2 18059 Rostock Germany
| | - Alexander G. Stepanov
- Boreskov Institute of CatalysisSiberian Branch of Russian Academy of Sciences Prospekt Akademika Lavrentieva 5 Novosibirsk 630090 Russia
- Novosibirsk State University Pirogova Street 2 Novosibirsk 630090 Russia
| | - Daniil I. Kolokolov
- Boreskov Institute of CatalysisSiberian 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 RostockInstitut für ChemieAbteilung für Physikalische Chemie Dr.-Lorenz-Weg 2 18059 Rostock Germany
- Department LL&MUniversity 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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39
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Wiedemann C, Hempel G, Bordusa F. Reorientation dynamics and ion diffusivity of neat dimethylimidazolium dimethylphosphate probed by NMR spectroscopy. RSC Adv 2019; 9:35735-35750. [PMID: 35528082 PMCID: PMC9074696 DOI: 10.1039/c9ra07731f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 10/28/2019] [Indexed: 11/21/2022] Open
Abstract
NMR spectroscopy at two magnetic field strengths was employed to investigate the dynamics of dimethylimidazolium dimethylphosphate ([C1C1IM][(CH3)2PO4]). [C1C1IM][(CH3)2PO4] is a low-melting, halogen-free ionic liquid comprising of only methyl groups. 13C spin-lattice relaxation rates as well as self-diffusion coefficients were measured for [C1C1IM][(CH3)2PO4] as a function of temperature. The rotational correlation times, τ c, for the cation and the anion were obtained from the 13C spin-lattice relaxation rates. Although from a theoretical point of view cations and anions are similar in size, they show different reorientation mobilities and diffusivities. The self-diffusion coefficients and the rotational correlation times were related to the radii of the diffusing spheres. The analysis reveals that the radii of the cation and the anion, respectively, are different from each other but constant at temperatures ranging from 293 to 353 K. The experimental results are rationalised by a discrete and individual cation and anion diffusion. The [(CH3)2PO4]- anion reorients faster compared to the cation but diffuses significantly slower indicating the formation of anionic aggregates. Relaxation data were acquired with standard liquid and magic-angle-spinning NMR probes to estimate residual dipolar interactions, chemical shift anisotropy or differences in magnetic susceptibility within the sample.
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Affiliation(s)
- Christoph Wiedemann
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg Kurt-Mothes-Str. 3a D-06120 Halle (Saale) Germany
| | - Günter Hempel
- Institute of Physics, Martin Luther University Halle-Wittenberg Betty-Heimann-Str. 7 D-06120 Halle (Saale) Germany
| | - Frank Bordusa
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg Kurt-Mothes-Str. 3a D-06120 Halle (Saale) Germany
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40
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Niemann T, Neumann J, Stange P, Gärtner S, Youngs TGA, Paschek D, Warr GG, Atkin R, Ludwig R. Die zweigesichtige Natur der Wasserstoffbrückenbindung in hydroxylfunktionalisierten ionischen Flüssigkeiten, offenbart durch Neutronendiffraktometrie und Molekulardynamik‐Simulation. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201904712] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Thomas Niemann
- Universität Rostock Institut für Chemie Abteilung für Physikalische Chemie Dr.-Lorenz-Weg 2 18059 Rostock Deutschland
| | - Jan Neumann
- Universität Rostock Institut für Chemie Abteilung für Physikalische Chemie Albert-Einstein-Str. 21 18059 Rostock Deutschland
| | - Peter Stange
- Universität Rostock Institut für Chemie Abteilung für Physikalische Chemie Dr.-Lorenz-Weg 2 18059 Rostock Deutschland
| | - Sabrina Gärtner
- ISIS Faculty, STFC Rutherford Appleton Laboratory Didcot OX11 0QX UK
| | | | - Dietmar Paschek
- Universität Rostock Institut für Chemie Abteilung für Physikalische Chemie Albert-Einstein-Str. 21 18059 Rostock Deutschland
| | - Gregory G. Warr
- School of Chemistry and Sydney Nano The University of Sydney NSW 2006 Australien
| | - Rob Atkin
- School of Molecular Sciences The University of Western Australia Perth Western Australia 6009 Australien
| | - Ralf Ludwig
- Universität Rostock Institut für Chemie Abteilung für Physikalische Chemie Dr.-Lorenz-Weg 2 18059 Rostock Deutschland
- Department LL&M University of Rostock Albert-Einstein-Str. 25 18059 Rostock Deutschland
- Leibniz-Institut für Katalyse an der Universität Rostock e.V. Albert-Einstein-Str. 29a 18059 Rostock Deutschland
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41
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Zeng HJ, Johnson MA, Ramdihal JD, Sumner RA, Rodriguez C, Lall-Ramnarine SI, Wishart JF. Spectroscopic Assessment of Intra- and Intermolecular Hydrogen Bonding in Ether-Functionalized Imidazolium Ionic Liquids. J Phys Chem A 2019; 123:8370-8376. [DOI: 10.1021/acs.jpca.9b04345] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Helen J. Zeng
- 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
| | - Jasodra D. Ramdihal
- Chemistry Department, Queensborough Community College of the City University of New York, Bayside, New York 11364, United States
| | - Rawlric A. Sumner
- Chemistry Department, Queensborough Community College of the City University of New York, Bayside, New York 11364, United States
| | - Chanele Rodriguez
- Chemistry Department, Queensborough Community College of the City University of New York, Bayside, New York 11364, United States
| | - Sharon I. Lall-Ramnarine
- Chemistry Department, Queensborough Community College of the City University of New York, Bayside, New York 11364, United States
| | - James F. Wishart
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, United States
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42
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Niemann T, Neumann J, Stange P, Gärtner S, Youngs TGA, Paschek D, Warr GG, Atkin R, Ludwig R. The Double-Faced Nature of Hydrogen Bonding in Hydroxy-Functionalized Ionic Liquids Shown by Neutron Diffraction and Molecular Dynamics Simulations. Angew Chem Int Ed Engl 2019; 58:12887-12892. [PMID: 31177605 DOI: 10.1002/anie.201904712] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/25/2019] [Indexed: 01/14/2023]
Abstract
We characterize the double-faced nature of hydrogen bonding in hydroxy-functionalized ionic liquids by means of neutron diffraction with isotopic substitution (NDIS), molecular dynamics (MD) simulations, and quantum chemical calculations. NDIS data are fit using the empirical potential structure refinement technique (EPSR) to elucidate the nearest neighbor H⋅⋅⋅O and O⋅⋅⋅O pair distribution functions for hydrogen bonds between ions of opposite charge and the same charge. Despite the presence of repulsive Coulomb forces, the cation-cation interaction is stronger than the cation-anion interaction. We compare the hydrogen-bond geometries of both "doubly charged hydrogen bonds" with those reported for molecular liquids, such as water and alcohols. In combination, the NDIS measurements and MD simulations reveal the subtle balance between the two types of hydrogen bonds: The small transition enthalpy suggests that the elusive like-charge attraction is almost competitive with conventional ion-pair formation.
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Affiliation(s)
- Thomas Niemann
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 2, 18059, Rostock, Germany
| | - Jan Neumann
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Albert-Einstein-Strasse 21, 18059, Rostock, Germany
| | - Peter Stange
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 2, 18059, Rostock, Germany
| | - Sabrina Gärtner
- ISIS Faculty, STFC, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Tristan G A Youngs
- ISIS Faculty, STFC, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Dietmar Paschek
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Albert-Einstein-Strasse 21, 18059, Rostock, Germany
| | - Gregory G Warr
- School of Chemistry and Sydney Nano, The University of Sydney, NSW, 2006, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Ralf Ludwig
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, 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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43
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Le Donne A, Adenusi H, Porcelli F, Bodo E. Structural Features of Cholinium Based Protic Ionic Liquids through Molecular Dynamics. J Phys Chem B 2019; 123:5568-5576. [PMID: 31185161 DOI: 10.1021/acs.jpcb.9b03314] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
An analysis of the complex proton transfer processes in certain protic ionic liquids, based on amino acid anions, has been carried out through ab initio molecular dynamics in the view of finding naturally conductive and pure mediums. The systems analyzed here might serve as chemical prototypes for pure and dry ionic liquids where mobile protons can act as fast charge carriers. We have exploited the natural tendency of these liquids to form a complex network of hydrogen bonds. The presence of such a network allows the naturally repulsive interaction between like charge ions to be weakened to the point that a proton migration process inside the anionic component of the fluid becomes possible. We have also seen that the extent of these proton migrations is sizable for carboxylic based amino acid anions, while it is very limited for sulfur containing ones.
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Affiliation(s)
- Andrea Le Donne
- Chemistry Department , University of Rome "La Sapienza" , Piazzale Aldo Moro 5 , 00185 Rome , Italy
| | - Henry Adenusi
- Chemistry Department , University of Rome "La Sapienza" , Piazzale Aldo Moro 5 , 00185 Rome , Italy
| | - Francesco Porcelli
- Chemistry Department , University of Rome "La Sapienza" , Piazzale Aldo Moro 5 , 00185 Rome , Italy
| | - Enrico Bodo
- Chemistry Department , University of Rome "La Sapienza" , Piazzale Aldo Moro 5 , 00185 Rome , Italy
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44
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Panja SK, Haddad B, Debdab M, Kiefer J, Chaker Y, Bresson S, Paolone A. Cluster Formation through Hydrogen Bond Bridges across Chloride Anions in a Hydroxyl-Functionalized Ionic Liquid. Chemphyschem 2019; 20:936-940. [PMID: 30821876 DOI: 10.1002/cphc.201801206] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 03/01/2019] [Indexed: 11/10/2022]
Abstract
Several recent studies of hydroxyl-functionalized ionic liquids (ILs) have shown that cation-cation interactions can be dominating these materials at the molecular level when the anion involved is weakly interacting. The hydrogen bonds between the like ions led to the formation of interesting chain-like, ring-like, or distinct dimeric (i. e. two ion pairs) supermolecular clusters. In the present work, vibrational spectroscopy (ATR-IR and Raman) and density functional theory (DFT) calculations of the hydroxyl-functionalized imidazolium ionic liquid C2 OHmimCl indicate that anion-cation hydrogen bonding interactions are dominating, leading to the formation of distinct dimeric ion pair clusters. In this arrangement, the Cl- anions function as a bridge between the cations by establishing bifurcated hydrogen bonds with the OH group of one cation and the C(2)-H of another cation. Cation-cation interactions, on the other hand, do not play a significant role in the observed clusters.
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Affiliation(s)
- Sumit Kumar Panja
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, Karnataka, India
| | - Boumediene Haddad
- Department of Chemistry, Dr Moulay Tahar University of Saida, Algeria
| | - Mansour Debdab
- Laboratoire de Synthèse et Catalyse Tiaret LSCT, University of Tiaret, Algeria
| | - Johannes Kiefer
- Technische Thermodynamik, Universität Bremen, Badgasteiner Str. 1, 28359, Bremen, Germany
| | - Yassine Chaker
- Laboratoire de Synthèse et Catalyse Tiaret LSCT, University of Tiaret, Algeria
| | - Serge Bresson
- Laboratoire de Physique des Systèmes Complexes, Université Picardie Jules Verne, 33 rue St Leu, 80039, Amiens cedex, France
| | - Annalisa Paolone
- Consiglio Nazionale delle Ricerche Instituto dei Sistemi Complessi (CNR-ISC), University of Rome La Sapienza, Piazzale A. Moro 5, 00185, Roma, Italy
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45
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Zaitsau DH, Neumann J, Niemann T, Strate A, Paschek D, Verevkin SP, Ludwig R. Isolating the role of hydrogen bonding in hydroxyl-functionalized ionic liquids by means of vaporization enthalpies, infrared spectroscopy and molecular dynamics simulations. Phys Chem Chem Phys 2019; 21:20308-20314. [DOI: 10.1039/c9cp04337c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Hydrogen bonding in hydroxyl-functionalized ionic liquids (right) prevents favourable dispersion interaction between cation and anion (left). We analyze this subtle balance of interactions by combining calorimetry, IR spectroscopy and MD simulations.
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Affiliation(s)
- Dzmitry H. Zaitsau
- Universität Rostock
- Institut für Chemie
- Abteilung für Physikalische Chemie
- Rostock
- Germany
| | - Jan Neumann
- Universität Rostock
- Institut für Chemie
- Abteilung für Physikalische Chemie
- Rostock
- Germany
| | - Thomas Niemann
- Universität Rostock
- Institut für Chemie
- Abteilung für Physikalische Chemie
- Rostock
- Germany
| | - Anne Strate
- Universität Rostock
- Institut für Chemie
- Abteilung für Physikalische Chemie
- Rostock
- Germany
| | - Dietmar Paschek
- Universität Rostock
- Institut für Chemie
- Abteilung für Physikalische Chemie
- Rostock
- Germany
| | - Sergey P. Verevkin
- Universität Rostock
- Institut für Chemie
- Abteilung für Physikalische Chemie
- Rostock
- Germany
| | - Ralf Ludwig
- Universität Rostock
- Institut für Chemie
- Abteilung für Physikalische Chemie
- Rostock
- Germany
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46
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Niemann T, Stange P, Strate A, Ludwig R. When hydrogen bonding overcomes Coulomb repulsion: from kinetic to thermodynamic stability of cationic dimers. Phys Chem Chem Phys 2019; 21:8215-8220. [PMID: 30672530 DOI: 10.1039/c8cp06417b] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Quantum chemical calculations have been employed to study the kinetic and thermodynamic stability of hydroxy-functionalized 1-(3-hydroxyalkyl)pyridinium cationic dimers. For [Py-(CH2)n-OH+]2 structures with n = 2-17 we have calculated the robust local minima with clear dissociation barriers preventing their "Coulomb explosion" into separated cations. For n = 15 hydrogen bonding and dispersion forces fully compensate for the repulsive Coulomb forces between the cations allowing for the quantification of the pure hydrogen bond in the order of 20 kJ mol-1. The increasing kinetic stability even turns to thermodynamic stability with further elongated hydroxyalkyl chains. Now, quantum-type short-range attraction wins over classical long-range electrostatic repulsion resulting in negative binding energies and providing the first thermodynamically stable cationic dimers. The electronic, structural and spectroscopic signatures of the cationic dimers could be correlated to NBO parameters, supporting the existence of anti-electrostatic hydrogen bonds (AEHB) as recently suggested by Weinhold. In principle, these pure cationic dimers should be detectable in gas-phase experiments at low temperatures without the need of mediating molecules or counteranions.
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Affiliation(s)
- T Niemann
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 2, 18059, Rostock, Germany.
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47
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Niemann T, Strate A, Ludwig R, Zeng HJ, Menges FS, Johnson MA. Cooperatively enhanced hydrogen bonds in ionic liquids: closing the loop with molecular mimics of hydroxy-functionalized cations. Phys Chem Chem Phys 2019; 21:18092-18098. [DOI: 10.1039/c9cp03300a] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The combined experimental and theoretical approach for the gas and the liquid phases provides a quantitative understanding of the competition between differently H-bonded and charged constituents in liquids.
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Affiliation(s)
- Thomas Niemann
- Department of Chemistry
- University of Rostock
- 18059 Rostock
- Germany
- Department Life
| | - Anne Strate
- Department of Chemistry
- University of Rostock
- 18059 Rostock
- Germany
- Department Life
| | - Ralf Ludwig
- Department of Chemistry
- University of Rostock
- 18059 Rostock
- Germany
- Department Life
| | - Helen J. Zeng
- Sterling Chemistry Laboratory
- Yale University
- New Haven
- USA
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48
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Niemann T, Strate A, Ludwig R, Zeng HJ, Menges FS, Johnson MA. Spektroskopischer Nachweis einer attraktiven Kation‐Kation‐ Wechselwirkung in OH‐funktionalisierten ionischen Flüssigkeiten: ein H‐Brücken‐gebundenes kettenförmiges Trimer. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201808381] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Thomas Niemann
- Institut für Chemie Universität Rostock 18059 Rostock Deutschland
- Institut für Leben, Licht & Materie Universität Rostock 18051 Rostock Deutschland
| | - Anne Strate
- Institut für Chemie Universität Rostock 18059 Rostock Deutschland
- Institut für Leben, Licht & Materie Universität Rostock 18051 Rostock Deutschland
| | - Ralf Ludwig
- Institut für Chemie Universität Rostock 18059 Rostock Deutschland
- Institut für Leben, Licht & Materie Universität Rostock 18051 Rostock Deutschland
- Leibniz-Institut für Katalyse e.V. Albert-Einstein-Straße 29a 18059 Rostock Deutschland
| | - Helen J. Zeng
- Sterling Chemistry Laboratory Universität Yale New Haven CT 06520 USA
| | - Fabian S. Menges
- Sterling Chemistry Laboratory Universität Yale New Haven CT 06520 USA
| | - Mark A. Johnson
- Sterling Chemistry Laboratory Universität Yale New Haven CT 06520 USA
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49
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Niemann T, Strate A, Ludwig R, Zeng HJ, Menges FS, Johnson MA. Spectroscopic Evidence for an Attractive Cation-Cation Interaction in Hydroxy-Functionalized Ionic Liquids: A Hydrogen-Bonded Chain-like Trimer. Angew Chem Int Ed Engl 2018; 57:15364-15368. [PMID: 30303295 DOI: 10.1002/anie.201808381] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Indexed: 12/29/2022]
Abstract
We address the formation of hydrogen bonded domains among the cationic constituents of the ionic liquid (IL) 1-(3-hydroxypropyl)pyridinium tetrafluoroborate [HPPy][BF4 ] by means of cryogenic ion vibrational predissociation spectroscopy of cold (ca. 35 K) gas-phase cluster ions and quantum chemistry. Specifically, analysis of the OH stretching bands reveals a chain-like OH⋅⋅⋅OH⋅⋅⋅OH⋅⋅⋅BF4 - binding motif involving the three cations in the cationic quinary cluster ion (HPPy+ )3 (BF4 - )2 . Calculations show that this cooperative H-bond attraction compensates for the repulsive Coulomb forces and results in stable complexes that successfully compete with those in which the OH groups are predominantly attached to the counter anions. Our combined experimental and theoretical approach provides insight into the cooperative effects that lead to the formation of hydrogen bonded domains involving the cationic constituents of ILs.
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Affiliation(s)
- Thomas Niemann
- Department of Chemistry, University of Rostock, 18059, Rostock, Germany.,Department Life, Light & Matter, University of Rostock, 18051, Rostock, Germany
| | - Anne Strate
- 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
| | - Helen J Zeng
- Sterling Chemistry Laboratory, Yale University, New Haven, CT, 06520, USA
| | - Fabian S Menges
- Sterling Chemistry Laboratory, Yale University, New Haven, CT, 06520, USA
| | - Mark A Johnson
- Sterling Chemistry Laboratory, Yale University, New Haven, CT, 06520, USA
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