Synthesis, experimental and theoretical vibrational studies of 1-methyl and 1,2-dimethyl, 3-propyl imidazolium bis(trifluoromethanesulfonyl) imide

Abstract

In this study, two ionic liquids containing the bis(trifluoromethanesulfonyl)imide ([(CF 3 SO 2) 2 N − ]) anion are synthesized. The syntheses are based on an alkylation reaction of 1-methyl imidazole and 1,2-dimethyl imidazole followed by anion exchange. The obtained ILs are characterized by 1 H-NMR, 13 C-NMR, 19 F-NMR and FT-IR spectroscopy. Vibrational spectroscopy studies were conducted by infrared (FTIR/ATR), Raman spectroscopy and DFT calculations. The presence of methylation in the C2 position gives rise to specific marker bands in the Raman and IR spectra. In order to ascertain whether cation conformers are present in our ionic liquids, a computational study was performed using the density functional theory. The comparison of the experimental data and the computed spectra shows that three conformers of the imidazolium ions are present in both ionic liquids.

Electrochemical and Physical Properties of Imidazolium Chloride Ionic Liquids with Pyrrolidinium or Piperidinium Cation Addition and Their Application in Dual‐Ion Batteries

“…[ 17 ] AlCl 4 − was detected in all the three electrolytes, corresponding to a Raman shift of ≈353 cm −1 , [ 17 ] and the Raman shifts of ≈702 and ≈726 cm −1 were assigned to DMPI + (Figure 2a). [ 18 ] Noticeably, the Raman shift of the P 13 + peak may overlap with that of AlCl 4 − at ≈353 cm −1 [ 19 ] to form a stronger peak; therefore, the intensity percentage of I 353 /I 523 of P 13 Cl mixed ILs was higher than that of PP 14 Cl mixed ILs (compare Figure 2a,b). A shoulder peak at around 380 cm −1 was also ascribed to P 13 + (Figure 2a).…”

Synthesis, thermal properties, vibrational spectra and computational studies of Trioctylmethylammonium bis(trifluoromethylsulfonyl)imide ionic liquid

“…Hence, the weak Raman band at 962 cm -1 is assigned to that vibration mode of both species. The S-N stretching mode is predicted in the anion at 684 cm -1 while in IL at 714 cm -1 .Hence, the IR and Raman bands at 655 and 737 cm -1 respectively can be assigned to the symmetric deformation of CF 3 group and to the wagging mode of SO 2 group of anion and IL, respectively [70]. Both bands can also be simultaneously assigned to CH 2 twisting modes of cation.…”

Synthesis, thermal stability, vibrational spectra and conformational studies of novel dicationic meta-xylyl linked bis-1-methylimidazolium ionic liquids

“…According to literature [42][43][44][45], all fundamental vibrations of the [NTf2]anion are situated below 1400 cm -1 , then two SO2 antisymmetric stretching modes are expected between 1335 and 1352 cm -1 and the symmetric one, νs SO2 (1160 cm -1 ), with contributions from the νs CF3 symmetric stretching (intense polarized band at 1244 cm -1 ) [70]. In monocationic ionic liquids, the chloride was found in the plane of the ring, while BF4 is positioned over the ring and has short contacts not only with H-C ( 2), but also with a proton of the methyl group, as suggested by Katsyuba et al…”