Peculiarities of NMR Relaxation in Ionic Liquids: Difficulties in Interpretation and Novel Possibilities

Molecular Mobility in a Set of Imidazolium-Based Ionic Liquids [bmim]+A– by the NMR-Relaxation Method

“…Many 1 H curves are fitted perfectly by the SBPP model, which corresponds to a single basic motion in the used temperature range, but in some cases, the shapes of the 1 H experimental curves are more complex than one predicted by eq 1, and it means that 1 H relaxation dependencies reflect several types of reorientations. 57,64,65 It is worth noting that for both types of nuclei, the maximum in the relaxation rates is not achieved for all functional groups.…”

“…The latter effect was reported earlier for some other ILs. 55,57,64 The shape of the dependencies and maximum positions vary noticeably for different ILs, i.e., the anion significantly changes the rotational mobility of the [bmim] + cation. To the best of our knowledge, the temperature dependencies of the relaxation rates for ILs of the [bmim] type with NO 3 − , Cl − , Br − , and I − anions have been measured for the first time.…”

“…Some other significant results on IL/RTILs have been presented and discussed in many reviews. 4,7,19,20,30,64,65 Despite numerous works, some important gaps in studies still remain. One of those gaps is the absence of multinuclear NMR relaxation experiments for the wide series of neat RTILs with altering anions or cations, similar to what was done in the study of chemical shifts or self-diffusion coefficients.…”

“…Naturally, we could overview only a limited number of works in the outlined area. Some other significant results on IL/RTILs have been presented and discussed in many reviews. ,,,,,, Despite numerous works, some important gaps in studies still remain. One of those gaps is the absence of multinuclear NMR relaxation experiments for the wide series of neat RTILs with altering anions or cations, similar to what was done in the study of chemical shifts or self-diffusion coefficients. ,, The relaxation data would be very helpful to provide more insight into fine dynamical effects in the neat/bulk RTILs.…”

Translational Diffusion in a Set of Imidazolium-Based Ionic Liquids [bmim]+A– and Their Mixtures with Water

“…A more detailed overview of works in the outlined area is presented in papers and reviews. ,,,,,,− ,,− Note in addition that in a series of works, Abe and co-authors − hypothesized the existence of “water pockets” in the structure of solutions at a water concentration of approximately 70–90 mol %. It was reported that such formations manifested an abnormal behavior of water, and we discuss here the problem in details.…”