¹⁵N NMR spectra of some ionic liquids based on 1,3‐disubstituted imidazolium cations

Abstract

15N NMR spectra of twelve neat ionic liquids derived from 1,3-disubstituted imidazolium salts were measured, and effects of nitrogen atoms substitution, type of anions and influence of solvents used for dilution of neat ionic liquids were studied. Changes in charge distribution are discussed.

The alkali stability of radiation-grafted anion-exchange membranes containing pendent 1-benzyl-2,3-dimethylimidazolium head-groups

“…20 The imidazolium 15 N signals for BMMI are shifted slightly up-field to d N = 2197 and 2211 due to the additional methyl group (Fig. 5).…”

Magnetic resonance spectroscopy in ionic liquids

“…Lyčka et al were the first to conduct 15 N measurements at natural abundance on twelve neat ionic liquids using inverse-gated 45°pulses as well as 1 H-15 N HMBC experiments [100]. One important piece of information gained from the experiments is the charge distribution between the nitrogen atoms of the cation.…”

The impact of the π‐electron conjugation on 15N, 13C and 1H NMR chemical shifts in push–pull benzothiazolium salts. Experimental and theoretical study

“…3) allowed us to differentiate between them, since protons of the dimethylamino group gave appropriate cross-peaks with the nitrogen of NMe 2 group, denoted as N-12 in the rest of the text, while a crosspeak with the hydrogens of N C -methyl group corresponds to the benzothiazolium nitrogen N-3. 31 The concentration dependence of the 15 N shifts in [3-Me-Btz]I was also tested (in the concentration range 0.005-0.10 mmol ml 1 ) and no deviations were observed. Comparison of the 15 N chemical shifts with that one of parent 2-methylbenzothiazolium iodide shows that the quaternary nitrogen N-3 of benzothiazolium ion is shielded due to the presence of dimethylamino group attached to the end of -conjugated bridge.…”