Cargando…
NMR Spectroscopic Studies of Cation Dynamics in Symmetrically-Substituted Imidazolium-Based Ionic Liquid Crystals
Ionic liquid crystals (ILCs) present a new class of non-molecular soft materials with a unique combination of high ionic conductivity and anisotropy of physicochemical properties. Symmetrically-substituted long-chain imidazolium-based mesogenic ionic liquids exhibiting a smectic liquid crystalline p...
Autores principales: | , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2020
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7404116/ https://www.ncbi.nlm.nih.gov/pubmed/32708674 http://dx.doi.org/10.3390/ijms21145024 |
_version_ | 1783567081462038528 |
---|---|
author | Majhi, Debashis Komolkin, Andrei V. Dvinskikh, Sergey V. |
author_facet | Majhi, Debashis Komolkin, Andrei V. Dvinskikh, Sergey V. |
author_sort | Majhi, Debashis |
collection | PubMed |
description | Ionic liquid crystals (ILCs) present a new class of non-molecular soft materials with a unique combination of high ionic conductivity and anisotropy of physicochemical properties. Symmetrically-substituted long-chain imidazolium-based mesogenic ionic liquids exhibiting a smectic liquid crystalline phase were investigated by solid state NMR spectroscopy and computational methods. The aim of the study was to reveal the correlation between cation size and structure, local dynamics, and orientational order in the layered mesophase. The obtained experimental data are consistent with the model of a rod-shaped cation with the two chains aligned in opposite directions outward from the imidazolium core. The alignment of the core plane to the phase director and the restricted conformations of the chain segments were determined and compared to those in single-chain counterparts. The orientational order parameter S~0.5–0.6 of double-chain ionic liquid crystals is higher than that of corresponding single-chain analogues. This is compatible with the enhanced contribution of van der Waals forces to the stabilization of smectic layers. Increased orientational order for the material with Br(−) counterions, which exhibit a smaller ionic radius and higher ability to form hydrogen bonds as compared to that of BF(4)(−), also indicated a non-negligible influence of electrostatic and hydrogen bonding interactions. The enhanced rod-shape character and higher orientational order of symmetrically-substituted ILCs can offer additional opportunities in the design of self-assembling non-molecular materials. |
format | Online Article Text |
id | pubmed-7404116 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-74041162020-08-11 NMR Spectroscopic Studies of Cation Dynamics in Symmetrically-Substituted Imidazolium-Based Ionic Liquid Crystals Majhi, Debashis Komolkin, Andrei V. Dvinskikh, Sergey V. Int J Mol Sci Article Ionic liquid crystals (ILCs) present a new class of non-molecular soft materials with a unique combination of high ionic conductivity and anisotropy of physicochemical properties. Symmetrically-substituted long-chain imidazolium-based mesogenic ionic liquids exhibiting a smectic liquid crystalline phase were investigated by solid state NMR spectroscopy and computational methods. The aim of the study was to reveal the correlation between cation size and structure, local dynamics, and orientational order in the layered mesophase. The obtained experimental data are consistent with the model of a rod-shaped cation with the two chains aligned in opposite directions outward from the imidazolium core. The alignment of the core plane to the phase director and the restricted conformations of the chain segments were determined and compared to those in single-chain counterparts. The orientational order parameter S~0.5–0.6 of double-chain ionic liquid crystals is higher than that of corresponding single-chain analogues. This is compatible with the enhanced contribution of van der Waals forces to the stabilization of smectic layers. Increased orientational order for the material with Br(−) counterions, which exhibit a smaller ionic radius and higher ability to form hydrogen bonds as compared to that of BF(4)(−), also indicated a non-negligible influence of electrostatic and hydrogen bonding interactions. The enhanced rod-shape character and higher orientational order of symmetrically-substituted ILCs can offer additional opportunities in the design of self-assembling non-molecular materials. MDPI 2020-07-16 /pmc/articles/PMC7404116/ /pubmed/32708674 http://dx.doi.org/10.3390/ijms21145024 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Majhi, Debashis Komolkin, Andrei V. Dvinskikh, Sergey V. NMR Spectroscopic Studies of Cation Dynamics in Symmetrically-Substituted Imidazolium-Based Ionic Liquid Crystals |
title | NMR Spectroscopic Studies of Cation Dynamics in Symmetrically-Substituted Imidazolium-Based Ionic Liquid Crystals |
title_full | NMR Spectroscopic Studies of Cation Dynamics in Symmetrically-Substituted Imidazolium-Based Ionic Liquid Crystals |
title_fullStr | NMR Spectroscopic Studies of Cation Dynamics in Symmetrically-Substituted Imidazolium-Based Ionic Liquid Crystals |
title_full_unstemmed | NMR Spectroscopic Studies of Cation Dynamics in Symmetrically-Substituted Imidazolium-Based Ionic Liquid Crystals |
title_short | NMR Spectroscopic Studies of Cation Dynamics in Symmetrically-Substituted Imidazolium-Based Ionic Liquid Crystals |
title_sort | nmr spectroscopic studies of cation dynamics in symmetrically-substituted imidazolium-based ionic liquid crystals |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7404116/ https://www.ncbi.nlm.nih.gov/pubmed/32708674 http://dx.doi.org/10.3390/ijms21145024 |
work_keys_str_mv | AT majhidebashis nmrspectroscopicstudiesofcationdynamicsinsymmetricallysubstitutedimidazoliumbasedionicliquidcrystals AT komolkinandreiv nmrspectroscopicstudiesofcationdynamicsinsymmetricallysubstitutedimidazoliumbasedionicliquidcrystals AT dvinskikhsergeyv nmrspectroscopicstudiesofcationdynamicsinsymmetricallysubstitutedimidazoliumbasedionicliquidcrystals |