1
|
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.
Collapse
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
| |
Collapse
|
2
|
Khudozhitkov AE, Donoshita M, Stepanov AG, Philippi F, Rauber D, Hempelmann R, Kitagawa H, Kolokolov DI, Ludwig R. High‐Temperature Quantum Tunneling and Hydrogen Bonding Rearrangements Characterize the Solid‐Solid Phase Transitions in a Phosphonium‐Based Protic Ionic Liquid. Chemistry 2022; 28:e202200257. [PMID: 35187737 PMCID: PMC9311734 DOI: 10.1002/chem.202200257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Alexander E. Khudozhitkov
- Boreskov Institute of Catalysis Siberian Branch of Russian Academy of Sciences Prospekt Akademika Lavrentieva 5 Novosibirsk 630090 Russia
- Novosibirsk State University Pirogova Street 2 Novosibirsk 630090 Russia
| | - Masaki Donoshita
- Division of Chemistry Graduate School of Science Kyoto University Kitashirakawa-Oiwakecho, Sakyo-ku Kyoto 606-8502 Japan
| | - Alexander G. Stepanov
- Boreskov Institute of Catalysis Siberian Branch of Russian Academy of Sciences Prospekt Akademika Lavrentieva 5 Novosibirsk 630090 Russia
- Novosibirsk State University Pirogova Street 2 Novosibirsk 630090 Russia
| | - Frederik Philippi
- Physikalische Chemie Universität des Saarlandes Campus B2.2 66123 Saarbrücken Germany
| | - Daniel Rauber
- Physikalische Chemie Universität des Saarlandes Campus B2.2 66123 Saarbrücken Germany
| | - Rolf Hempelmann
- Physikalische Chemie Universität des Saarlandes Campus B2.2 66123 Saarbrücken Germany
| | - Hiroshi Kitagawa
- Division of Chemistry Graduate School of Science Kyoto University Kitashirakawa-Oiwakecho, Sakyo-ku Kyoto 606-8502 Japan
| | - Daniil I. Kolokolov
- Boreskov Institute of Catalysis Siberian Branch of Russian Academy of Sciences Prospekt Akademika Lavrentieva 5 Novosibirsk 630090 Russia
- Novosibirsk State University Pirogova Street 2 Novosibirsk 630090 Russia
| | - Ralf Ludwig
- Department LL&M University of Rostock Albert-Einstein-Str. 25 18059 Rostock Germany
- Institut für Chemie Abteilung für Physikalische Chemie Universität Rostock Dr.-Lorenz-Weg 2 18059 Rostock Germany
- Leibniz-Institut für Katalyse Universität Rostock e.V. Albert-Einstein-Str. 29a 18059 Rostock Germany
| |
Collapse
|
3
|
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]
|
4
|
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!
Collapse
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
| |
Collapse
|
5
|
Philipp JK, Fritsch S, Ludwig R. Cyclic Octamer of Hydroxyl-functionalized Cations with Net Charge Q=+8e Kinetically Stabilized by a 'Molecular Island' of Cooperative Hydrogen Bonds. Chemphyschem 2020; 21:2411-2416. [PMID: 32845043 PMCID: PMC7702028 DOI: 10.1002/cphc.202000681] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/20/2020] [Indexed: 11/07/2022]
Abstract
Cyclic octamers are well-known structural motifs in chemistry, biology and physics. These include covalently bound cyclic octameric sulphur, cylic octa-alkanes, cyclo-octameric peptides as well as hydrogen-bonded ring clusters of alcohols. In this work, we show that even calculated cyclic octamers of hydroxy-functionalized pyridinium cations with a net charge Q=+8e are kinetically stable. Eight positively charged cations are kept together by hydrogen bonding despite the strong Coulomb repulsive forces. Sufficiently long hydroxy-octyl chains prevent "Coulomb explosion" by increasing the distance between the positive charges at the pyridinium rings, reducing the Coulomb repulsion and thus strengthen hydrogen bonds between the OH groups. The eightfold positively charged cyclic octamer shows spectroscopic properties similar to those obtained for hydrogen-bonded neutral cyclic octamers of methanol. Thus, the area of the hydrogen bonded OH ring represents a 'molecular island' within an overall cationic environment. Although not observable, the spectroscopic properties and the correlated NBO parameters of the calculated cationic octamer support the detection of smaller cationic clusters in ionic liquids, which we observed despite the competition with ion pairs wherein attractive Coulomb forces enhance hydrogen bonding between cation and anion.
Collapse
Affiliation(s)
- Jule Kristin Philipp
- Universität RostockInstitut für ChemieAbteilung Physikalische und Theoretische ChemieDr.-Lorenz-Weg 218059RostockGermany
| | - Sebastian Fritsch
- Universität RostockInstitut für ChemieAbteilung Physikalische und Theoretische ChemieDr.-Lorenz-Weg 218059RostockGermany
| | - Ralf Ludwig
- Universität RostockInstitut für ChemieAbteilung Physikalische und Theoretische ChemieDr.-Lorenz-Weg 218059RostockGermany
- Universität RostockDepartment LL&MAlbert-Einstein-Str. 2518059RostockGermany
- Leibniz-Institut für Katalyse an der Universität Rostock e.V.Albert-Einstein-Str. 29a18059RostockGermany
| |
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
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
| |
Collapse
|
8
|
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] [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.
Collapse
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
| | - Jan Neumann
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 2, 18059, Rostock, Germany
| | - Thomas Niemann
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 2, 18059, Rostock, Germany
| | - Dzmitry Zaitsau
- 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
| | - Dietmar Paschek
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 2, 18059, Rostock, Germany
| | - Alexander G Stepanov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk, 630090, Russia.,Novosibirsk State University, Pirogova Street 2, Novosibirsk, 630090, Russia
| | - Daniil I Kolokolov
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk, 630090, Russia.,Novosibirsk State University, Pirogova Street 2, Novosibirsk, 630090, Russia
| | - Ralf Ludwig
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 2, 18059, Rostock, Germany.,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
| |
Collapse
|
9
|
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
| |
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|