Molecular mobility in several imidazolium-based ionic liquids according to data of 1 H and 13 C NMR relaxation

• Published in: Magnetic resonance in chemistry Vol. 56; no. 2; pp. 140 - 143
• Main Authors: Matveev, Vladimir V, Markelov, Denis A, Ievlev, Alexandr V, Brui, Ekaterina A, Tyutyukin, Konstantin V, Lähderanta, Erkki
• Format: Journal Article
• Language: English
• Published: England 01.02.2018
• Subjects: temperature dependence; emimOAc; ionic liquids; NMR relaxation; glycerol
• ISSN: 0749-1581; 1097-458X
• DOI: 10.1002/mrc.4681

Temperature dependences are compared for H and C NMR 1/T curves relaxation rates in three imidazolium-based ionic liquids (ILs), namely, in [bmim]PF , [bmim]BF , and [emim]CH COO. C curves show alike behavior for all three ILs and follow a well-known Bloembergen-Pound-Purcell (BPP) equation. On the contrary, an essential part of H curves differ strongly from corresponding C ones and also have different shapes for different ILs. For the first time, we have detected the specific, two-maximum shape of H relaxation curve for hydrogen atom of C(2)H group of the [emim]CH COO. Assuming that this maximum reflects the correlated rotation of several adjoining ion pairs, we have tried to destroy this rotation by addition of glycerol to the [emim]CH COO. The second, high-temperature maximum has disappeared in the [emim]CH COO-glycerol mixture, and this fact confirms our assumption. Copyright © 2017 John Wiley & Sons, Ltd.