TY - JOUR

T1 - Molecular mobility in several imidazolium-based ionic liquids according to data of 1H and 13C NMR relaxation

AU - Матвеев, Владимир Викторович

AU - Маркелов, Денис Анатольевич

AU - Иевлев, Александр Вячеславович

AU - Brui, Ekaterina A.

AU - Тютюкин, Константин Викторович

AU - Lähderanta, Erkki

N1 - Funding Information: The authors thank Petr V. Lukashev for his assistance in experiments and data fitting. The work was partly supported by Research Program of St. Petersburg State University, grant #11.42.676.2017 and by RFBR, grant #17-03-00057. The NMR measurements have been carried out partially in the Center for Magnetic Resonance of Research Park of St. Petersburg State University and partially in the Instrumental Centre of Chemical Department of University of Turku. V. V. M. and A. V. I. are grateful to the bilateral exchange program between University of Turku and St. Petersburg State University. E. A. B. thanks Lappeenranta University of Technology for support of the research work.

PY - 2018/2

Y1 - 2018/2

N2 - Temperature dependences are compared for 1H and 13C NMR 1/T 1 curves relaxation rates in three imidazolium-based ionic liquids (ILs), namely, in [bmim]PF 6, [bmim]BF 4, and [emim]CH 3COO. 13C 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 1H curves differ strongly from corresponding 13C ones and also have different shapes for different ILs. For the first time, we have detected the specific, two-maximum shape of 1H relaxation curve for hydrogen atom of C(2)H group of the [emim]CH 3COO. 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 3COO. The second, high-temperature maximum has disappeared in the [emim]CH 3COO–glycerol mixture, and this fact confirms our assumption.

AB - Temperature dependences are compared for 1H and 13C NMR 1/T 1 curves relaxation rates in three imidazolium-based ionic liquids (ILs), namely, in [bmim]PF 6, [bmim]BF 4, and [emim]CH 3COO. 13C 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 1H curves differ strongly from corresponding 13C ones and also have different shapes for different ILs. For the first time, we have detected the specific, two-maximum shape of 1H relaxation curve for hydrogen atom of C(2)H group of the [emim]CH 3COO. 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 3COO. The second, high-temperature maximum has disappeared in the [emim]CH 3COO–glycerol mixture, and this fact confirms our assumption.

KW - ЯМР-релаксометрия

KW - температурная зависимость

KW - ионные жидкости

KW - NMR relaxation

KW - emimOAc

KW - glycerol

KW - ionic liquids

KW - temperature dependence

KW - SYSTEM

KW - RATES

KW - 1-BUTYL-3-METHYLIMIDAZOLIUM HEXAFLUOROPHOSPHATE

KW - 1-ETHYL-3-METHYLIMIDAZOLIUM ACETATE

KW - REORIENTATIONAL DYNAMICS

UR - http://www.scopus.com/inward/record.url?scp=85036578790&partnerID=8YFLogxK

UR - http://www.mendeley.com/research/molecular-mobility-several-imidazoliumbased-ionic-liquids-according-data-1h-13c-nmr-relaxation

U2 - 10.1002/mrc.4681

DO - 10.1002/mrc.4681

M3 - Article

VL - 56

SP - 140

EP - 143

JO - Magnetic Resonance in Chemistry

JF - Magnetic Resonance in Chemistry

SN - 0749-1581

IS - 2

ER -