Structure and intermolecular interactions in ionic liquid 1‐ethyl‐3‐methylimidazolium bromide and its aqueous solutions investigated by vibrational spectroscopy and quantum chemical computations.
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| Title: | Structure and intermolecular interactions in ionic liquid 1‐ethyl‐3‐methylimidazolium bromide and its aqueous solutions investigated by vibrational spectroscopy and quantum chemical computations. |
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| Authors: | Katsyuba, Sergey A.1 (AUTHOR) skatsyuba@yahoo.com, Grimme, Stefan2 (AUTHOR) |
| Source: | Journal of Computational Chemistry. 12/15/2024, Vol. 45 Issue 32, p2719-2726. 8p. |
| Subjects: | Ion pairs, Vibrational spectra, Ionic interactions, Aqueous solutions, Quantum computing |
| Abstract: | The recently developed efficient protocol to explicit quantum mechanical modeling of structure and IR spectra of liquids and solutions (S. A. Katsyuba, S. Spicher, T. P. Gerasimova, S. Grimme, J. Phys. Chem. B 2020, 124, 6664) is applied to ionic liquid (IL) 1‐ethyl‐3‐methylimidazolium bromide (EmimBr), its C2‐deuterated analog [Emim‐d]Br and its aqueous solutions. It is shown that the solvation strongly modifies frequencies and IR intensities of the CH/CD stretching vibrations (νCH/νCD) of the imidazolium ring. The main vibrational spectroscopic features of the neat IL are reproduced by the simulations for a cluster (EmimBr)9, in which all three imidazolium CH moieties of the solvated cation form short contacts with three Br− anions, and another two Br− anions are located on top and bottom of imidazolium ring. Cluster models of aqueous solutions reproduce the experimental vibrational frequencies of actual solutions, provided that the Br− anion of solvated contact ion pair (CIP) is situated on top of imidazolium ring, and CH/CD moieties of the latter participate in short contacts with surrounding water molecules. Both structural and spectroscopic analysis allow to interpret the short contacts CH/CD⋯Br− and CH/CD⋯OH2 as hydrogen bonds of approximately equal strength. Enthalpies of bonding of these liquid‐state H‐bonds, estimated with the use of empirical correlations, amount to ca. 1.4 kcal⋅mol−1, while the analogous estimates obtained for the gas‐phase charged species [Emim]2Br+ increase to 5.6 kcal⋅mol−1. It is shown that formation of solvent‐shared ion pair (SIP) in aqueous solution, where the counterions of IL are separated by two water molecules H‐bonded to a Br− anion, produces frequency shifts ΔνCH/CD, strongly different from the case of CIP formation. This difference can be used for IR/Raman spectroscopic differentiation of the type of solvated ion pairs of EmimBr or other related ILs. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Computational Chemistry is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 180775615 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Structure and intermolecular interactions in ionic liquid 1‐ethyl‐3‐methylimidazolium bromide and its aqueous solutions investigated by vibrational spectroscopy and quantum chemical computations. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Katsyuba%2C+Sergey+A%2E%22">Katsyuba, Sergey A.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> skatsyuba@yahoo.com</i><br /><searchLink fieldCode="AR" term="%22Grimme%2C+Stefan%22">Grimme, Stefan</searchLink><relatesTo>2</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Computational+Chemistry%22">Journal of Computational Chemistry</searchLink>. 12/15/2024, Vol. 45 Issue 32, p2719-2726. 8p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Ion+pairs%22">Ion pairs</searchLink><br /><searchLink fieldCode="DE" term="%22Vibrational+spectra%22">Vibrational spectra</searchLink><br /><searchLink fieldCode="DE" term="%22Ionic+interactions%22">Ionic interactions</searchLink><br /><searchLink fieldCode="DE" term="%22Aqueous+solutions%22">Aqueous solutions</searchLink><br /><searchLink fieldCode="DE" term="%22Quantum+computing%22">Quantum computing</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The recently developed efficient protocol to explicit quantum mechanical modeling of structure and IR spectra of liquids and solutions (S. A. Katsyuba, S. Spicher, T. P. Gerasimova, S. Grimme, J. Phys. Chem. B 2020, 124, 6664) is applied to ionic liquid (IL) 1‐ethyl‐3‐methylimidazolium bromide (EmimBr), its C2‐deuterated analog [Emim‐d]Br and its aqueous solutions. It is shown that the solvation strongly modifies frequencies and IR intensities of the CH/CD stretching vibrations (νCH/νCD) of the imidazolium ring. The main vibrational spectroscopic features of the neat IL are reproduced by the simulations for a cluster (EmimBr)9, in which all three imidazolium CH moieties of the solvated cation form short contacts with three Br− anions, and another two Br− anions are located on top and bottom of imidazolium ring. Cluster models of aqueous solutions reproduce the experimental vibrational frequencies of actual solutions, provided that the Br− anion of solvated contact ion pair (CIP) is situated on top of imidazolium ring, and CH/CD moieties of the latter participate in short contacts with surrounding water molecules. Both structural and spectroscopic analysis allow to interpret the short contacts CH/CD⋯Br− and CH/CD⋯OH2 as hydrogen bonds of approximately equal strength. Enthalpies of bonding of these liquid‐state H‐bonds, estimated with the use of empirical correlations, amount to ca. 1.4 kcal⋅mol−1, while the analogous estimates obtained for the gas‐phase charged species [Emim]2Br+ increase to 5.6 kcal⋅mol−1. It is shown that formation of solvent‐shared ion pair (SIP) in aqueous solution, where the counterions of IL are separated by two water molecules H‐bonded to a Br− anion, produces frequency shifts ΔνCH/CD, strongly different from the case of CIP formation. This difference can be used for IR/Raman spectroscopic differentiation of the type of solvated ion pairs of EmimBr or other related ILs. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Computational Chemistry is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1002/jcc.27472 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 8 StartPage: 2719 Subjects: – SubjectFull: Ion pairs Type: general – SubjectFull: Vibrational spectra Type: general – SubjectFull: Ionic interactions Type: general – SubjectFull: Aqueous solutions Type: general – SubjectFull: Quantum computing Type: general Titles: – TitleFull: Structure and intermolecular interactions in ionic liquid 1‐ethyl‐3‐methylimidazolium bromide and its aqueous solutions investigated by vibrational spectroscopy and quantum chemical computations. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Katsyuba, Sergey A. – PersonEntity: Name: NameFull: Grimme, Stefan IsPartOfRelationships: – BibEntity: Dates: – D: 15 M: 12 Text: 12/15/2024 Type: published Y: 2024 Identifiers: – Type: issn-print Value: 01928651 Numbering: – Type: volume Value: 45 – Type: issue Value: 32 Titles: – TitleFull: Journal of Computational Chemistry Type: main |
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