Issue 19, 2018

On the measurement of intermolecular heteronuclear cross relaxation rates in ionic liquids

Abstract

The HOESY (Heteronuclear Overhauser Effect SpectroscopY) NMR experiment is commonly used to study interactions and structuring in ionic liquids (ILs) via the measurement of the cross relaxation rate σ between two spins. In the intermolecular case, σ is proportional to rn, where r is the internuclear distance and n can vary between 1 and 6 depending on the frequency of the nuclei and their dynamics, thus σ can potentially provide detailed information on the liquid phase structure. However, in HOESY studies of ILs only relative values for σ are typically reported, making comparisons between different samples difficult. Herein we discuss the quantitative measurement of intermolecular cross relaxation rates based on the normalisation of HOESY signal intensities to the nuclear Boltzmann polarisation, demonstrated for 7Li–1H spin pairs in a lithium-containing pyrrolidinum-based ionic liquid electrolyte. We also use a simple model based on diffusing hard spheres for interpreting these quantities in terms of a distance of closest approach.

Graphical abstract: On the measurement of intermolecular heteronuclear cross relaxation rates in ionic liquids

Supplementary files

Article information

Article type
Paper
Submitted
08 Feb 2018
Accepted
25 Apr 2018
First published
25 Apr 2018

Phys. Chem. Chem. Phys., 2018,20, 13357-13364

On the measurement of intermolecular heteronuclear cross relaxation rates in ionic liquids

P. Martin, E. Salager, M. Forsyth, L. A. O’Dell and M. Deschamps, Phys. Chem. Chem. Phys., 2018, 20, 13357 DOI: 10.1039/C8CP00911B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements