We explore the structure of two ionic liquids based on the choline cation and the monoanion of the maleic acid. We consider two isomers of the anion (H-maleate, the cis-isomer and H-fumarate, the trans-isomer) having different physical chemical properties. H-maleate assumes a closed structure and forms a strong intramolecular hydrogen bond whereas H-fumarate has an open structure. X-ray diffraction, infrared and Raman spectroscopy and molecular dynamics have been used to provide a reliable picture of the interactions which characterize the structure of the fluids. All calculations indicate that the choline cation prefers to connect mainly to the carboxylate group through OH· · ·O interactions in both the compounds and orient the charged head N(CH3 )+3 toward the negative portion of the anion. However, the different structure of the two anions affects the distribution of the ionic components in the fluid. The trans conformation of H-fumarate allows further interactions between anions through COOH and CO –2 groups whereas intramolecular hydrogen bonding in H-maleate prevents this association. Our theoretical findings have been validated by comparing them with experimental X-ray data and infrared and Raman spectra.

Choline Hydrogen Dicarboxylate Ionic Liquids by X-ray Scattering, Vibrational Spectroscopy and Molecular Dynamics: H-Fumarate and H-Maleate and Their Conformations / Di Muzio, Simone; Ramondo, Fabio; Gontrani, Lorenzo; Ferella, Francesco; Nardone, Michele; Benassi, Paola. - In: MOLECULES. - ISSN 1420-3049. - 25:21(2020), pp. 1-20. [10.3390/molecules25214990]

Choline Hydrogen Dicarboxylate Ionic Liquids by X-ray Scattering, Vibrational Spectroscopy and Molecular Dynamics: H-Fumarate and H-Maleate and Their Conformations

Di Muzio, Simone;Ramondo, Fabio
;
Gontrani, Lorenzo;Nardone, Michele;
2020

Abstract

We explore the structure of two ionic liquids based on the choline cation and the monoanion of the maleic acid. We consider two isomers of the anion (H-maleate, the cis-isomer and H-fumarate, the trans-isomer) having different physical chemical properties. H-maleate assumes a closed structure and forms a strong intramolecular hydrogen bond whereas H-fumarate has an open structure. X-ray diffraction, infrared and Raman spectroscopy and molecular dynamics have been used to provide a reliable picture of the interactions which characterize the structure of the fluids. All calculations indicate that the choline cation prefers to connect mainly to the carboxylate group through OH· · ·O interactions in both the compounds and orient the charged head N(CH3 )+3 toward the negative portion of the anion. However, the different structure of the two anions affects the distribution of the ionic components in the fluid. The trans conformation of H-fumarate allows further interactions between anions through COOH and CO –2 groups whereas intramolecular hydrogen bonding in H-maleate prevents this association. Our theoretical findings have been validated by comparing them with experimental X-ray data and infrared and Raman spectra.
2020
ionic liquids; structure; molecular dynamics; X-ray diffraction; vibrational spectroscopy
01 Pubblicazione su rivista::01a Articolo in rivista
Choline Hydrogen Dicarboxylate Ionic Liquids by X-ray Scattering, Vibrational Spectroscopy and Molecular Dynamics: H-Fumarate and H-Maleate and Their Conformations / Di Muzio, Simone; Ramondo, Fabio; Gontrani, Lorenzo; Ferella, Francesco; Nardone, Michele; Benassi, Paola. - In: MOLECULES. - ISSN 1420-3049. - 25:21(2020), pp. 1-20. [10.3390/molecules25214990]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1448961
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