КФУ. Карточка публикации. Temperature dependence of 1H NMR chemical shifts and diffusivity of confined ethylammonium nitrate ionic liquid

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TEMPERATURE DEPENDENCE OF 1H NMR CHEMICAL SHIFTS AND DIFFUSIVITY OF CONFINED ETHYLAMMONIUM NITRATE IONIC LIQUID

Форма представления

Статьи в зарубежных журналах и сборниках

Год публикации

2020

Язык

английский

Авторы, сотрудники КФУ

Гнездилов Олег Иванович, автор

Филиппов Андрей Васильевич, автор

Библиографическое описание на языке оригинала

Gnezdilov O.I, Antzutkin O.N, Gimatdinov R, Temperature dependence of 1H NMR chemical shifts and diffusivity of confined ethylammonium nitrate ionic liquid//Magnetic Resonance Imaging. - 2020. - Vol.74, Is.. - P.84-89.

Аннотация

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 hydrogenbonding network of the confined EAN. Exposure to the magnetic field leads to restitution of the hydrogenbonding (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.

Ключевые слова

ionic liquids, dynamic properties, diffusivities of ions, NMR relaxation, ethylammonium nitrate, Confinement of EAN, chemical shift, diffusion coefficients

Название журнала

Magnetic Resonance Imaging

URL

https://doi.org/10.1016/j.mri.2020.09.012

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https://repository.kpfu.ru/?p_id=240312

Полная запись метаданных

Поле DC	Значение	Язык
dc.contributor.author	Гнездилов Олег Иванович	ru_RU
dc.contributor.author	Филиппов Андрей Васильевич	ru_RU
dc.date.accessioned	2020-01-01T00:00:00Z	ru_RU
dc.date.available	2020-01-01T00:00:00Z	ru_RU
dc.date.issued	2020	ru_RU
dc.identifier.citation	Gnezdilov O.I, Antzutkin O.N, Gimatdinov R, Temperature dependence of 1H NMR chemical shifts and diffusivity of confined ethylammonium nitrate ionic liquid//Magnetic Resonance Imaging. - 2020. - Vol.74, Is.. - P.84-89.	ru_RU
dc.identifier.uri	https://repository.kpfu.ru/?p_id=240312	ru_RU
dc.description.abstract	Magnetic Resonance Imaging	ru_RU
dc.description.abstract	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 hydrogenbonding network of the confined EAN. Exposure to the magnetic field leads to restitution of the hydrogenbonding (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.	ru_RU
dc.language.iso	ru	ru_RU
dc.subject	ionic liquids	ru_RU
dc.subject	dynamic properties	ru_RU
dc.subject	diffusivities of ions	ru_RU
dc.subject	NMR relaxation	ru_RU
dc.subject	ethylammonium nitrate	ru_RU
dc.subject	Confinement of EAN	ru_RU
dc.subject	chemical shift	ru_RU
dc.subject	diffusion coefficients	ru_RU
dc.title	Temperature dependence of 1H NMR chemical shifts and diffusivity of confined ethylammonium nitrate ionic liquid	ru_RU
dc.type	Статьи в зарубежных журналах и сборниках	ru_RU