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Temperature dependence of <sup>1</sup>H NMR chemical shifts and diffusivity of confined ethylammonium nitrate ionic liquid

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dc.contributor.author Gnezdilov O.I.
dc.contributor.author Antzutkin O.N.
dc.contributor.author Gimatdinov R.
dc.contributor.author Filippov A.
dc.date.accessioned 2021-02-25T20:35:18Z
dc.date.available 2021-02-25T20:35:18Z
dc.date.issued 2020
dc.identifier.issn 0730-725X
dc.identifier.uri https://dspace.kpfu.ru/xmlui/handle/net/161880
dc.description.abstract © 2020 Elsevier Inc. Some ionic liquids (ILs) change their dynamic properties when placed in a confinement between polar surfaces (Filippov et al., Phys. Chem. Chem. Phys. 2018, 20, 6316). The diffusivities of ions and NMR relaxation times in these ILs also reversibly change under a strong static magnetic field. The mechanisms of these phenomena are not clear, but it has been suggested that they involve modified hydrogen-bonding networks formed in these ILs in the presence of polar surfaces. To obtain a better understanding of these effects, we performed temperature-dependent measurements of chemical shifts and diffusion coefficients for ethylammonium nitrate (EAN) IL in the bulk phase (IB) and confined in layers with a thickness of ~4 μm between quartz plates unexposed (I phase) and exposed (IMF phase) to a static magnetic field of 9.4 T. It was shown that the NMR chemical shift of NH3 protons of EAN in the I phase is strongly shifted upfield, ~0.0145 ppm/K, which is due to weakening of the hydrogen-bonding network of the confined EAN. Exposure to the magnetic field leads to restitution of the hydrogen-bonding (H-bonding network). The temperature dependences of diffusion coefficients follow the order D(I) > D(IB) > D(IMF) and can be described by a Vogel-Fulcher-Tammann approach with variation of the pre-exponential factor, which is determined by the strength of the H-bonding network. Confinement of EAN between plates (IB → I) is an endothermic process, while processes occurring in a magnetic field, I → IMF and IMF → I, are exothermic and endothermic, respectively.
dc.relation.ispartofseries Magnetic Resonance Imaging
dc.subject Diffusion
dc.subject Ion dynamics
dc.subject Magnetic field
dc.subject Phase transformations
dc.subject Restricted diffusion
dc.title Temperature dependence of <sup>1</sup>H NMR chemical shifts and diffusivity of confined ethylammonium nitrate ionic liquid
dc.type Article
dc.relation.ispartofseries-volume 74
dc.collection Публикации сотрудников КФУ
dc.relation.startpage 84
dc.source.id SCOPUS0730725X-2020-74-SID85091392441

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  • Публикации сотрудников КФУ Scopus [22633]
    Коллекция содержит публикации сотрудников Казанского федерального (до 2010 года Казанского государственного) университета, проиндексированные в БД Scopus, начиная с 1970г.

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