Hydrophobic, Highly Conductive Ambient-Temperature Molten Salts†

Ambient-Temperature Molten Salts Inorganic Chemistry, Vol. 35, No. 5, 1996 1177(s, 1H), 7.73-7.68 (2 overlapping t, 2H, J ) 2.2 Hz), 4.52 (t, 2H, J )5.9 Hz), 4.06 (s, 3H), 3.80 (t, 2H, J ) 5.0 Hz), 3.35 (s, 3H).1-(2,2,2-Trifluoroethyl)-3-methylimidazolium Trifluoromethanesulfonate(CF 3CH 2MeIm + TfO - ). The same procedure was used asfor MeOEtMeIm + TfO - . From 20.4 g (72.0 mol) of trifluoromethanesulfonicanhydride, 5.93 g (75 mmol) of pyridine, and 7.20 g (72 mmol)of 1,1,1-trifluoroethanol (Fluka, puriss.) there was obtained 6.20 g ofCF 3CH 2MeIm + TfO - (28%) as a light brown solid. Anal. Calcd forC 7H 8N 2O 3F 6S: C, 26.76; H, 2.57; N, 8.92; O, 15.28; F, 36.28; S, 15.28.Found: C, 27.10; H, 2.50; N, 9.15; O, 15.8; F, 36.03. 1H-NMR(acetone-d 3, δ/ppm relative to TMS): 9.34 (s, 1H), 7.91 (s, 1H), 7.87(t, 1H, J ) 2.5 Hz), 5.40 (q, 2H, J ) 10.7 Hz), 4.14 (s, 3H).1,3-Diethylimidazolium Trifluoromethanesulfonate (Et 2Im + TfO - ).The same procedure was used as for Me 2Im + TfO - . From 5.93 g (61.7mmol) of 1-ethylimidazole and 10.97 g (61.7 mmol) of ethyl triflate(Fluka, purum), there was obtained 15.9 g of Et 2Im + TfO - (94%). 1H-NMR (acetone-d 3, δ/ppm relative to TMS): 9.17 (s, 1H), 7.78 (d, 2H,J ) 2.0 Hz), 4.39 (q, 4H, J ) 8.8 Hz), 1.57 (t, 6H, J ) 9.0 Hz).1-Ethyl-2,3-dimethylimidazolium Trifluoromethanesulfonate (1-Et-2,3-Me 2Im + TfO - ). The same procedure was used as forMe 2Im + TfO - . From 5.93 g (61.7 mmol) of 1-ethylimidazole and 10.97g (61.7 mmol) of ethyl triflate (Fluka, purum), there was obtained 15.9gofEt 2Im + TfO - (94%). 1H-NMR (acetone-d 3, δ/ppm relative toTMS): 7.64 (d, 1H, J ) 2.8 Hz), 7.59 (d, 1H, J ) 2.8 Hz), 4.33 (q,2H, J ) 9.3 Hz), 3.94 (s, 2H), 2.78 (s, 3H), 1.49 (t, 3H, J ) 9.0 Hz).1-Ethyl-3,4-dimethylimidazolium Trifluoromethanesulfonate (1-Et-3,4-Me 2Im + TfO - ). The same procedure was used as forMe 2Im + TfO - . From 2.62 g (23.8 mmol) of 1-ethyl-4-methylimidazoleand 3.91 g (23.8 mmol) of methyl triflate, there was obtained 5.67 gof 1-Et-3,4-Me 2Im + TfO - (87%). 1H-NMR (acetone-d 3, δ/ppm relativeto TMS): 9.01 (s, 1H), 7.52 (s, 1H), 4.30 (t, 2H, J ) 9.2 Hz), 3.91 (s,3H), 2.39 (s, 3H), 1.53 (t, 3H, J ) 9.0 Hz). The product containsabout 5% 1-ethyl-3,5-dimethyl isomer (see 1-Et-3,4-Me 2Im + Tf 2N - ).1,3-Diethyl-4-methylimidazolium Trifluoromethanesulfonate (1,3-Et 2-4-MeIm + TfO - ). The same procedure was used as for Me 2Im + TfO - .From 4.43 g (40.2 mmol) of 1-ethyl-4-methylimidazole and 7.17 g (40.3mmol) of ethyl triflate, there was obtained 8.83 g of 1,3-Et 2-4-MeIm + -TfO - (76%). Anal. Calcd for C 9H 15N 2O 4F 3S: C, 37.50; H, 5.24; N,9.72; O, 16.65; F, 19.77; S, 11.12. Found: C, 36.70/37.03; H, 5.28/5.03; N, 9.32/9.58; O, 18.6; S, 11.35. 1H-NMR (acetone-d 3, δ/ppmrelative to TMS): 9.06 (d, 1H, J ) 2.0 Hz), 7.54 (s, 1H), 4.30 (m, 2H,J ) 9.2 and 2.5 Hz), 2.41 (s, 3H), 1.53 (t, 6H, J ) 9.0 Hz).1,2-Diethyl-3-methylimidazolium Trifluoromethanesulfonate (1,2-Et 2-3-MeIm + TfO - ). The same procedure was used as for Me 2Im + TfO - .From 5.60 g (45.2 mmol) of 1,2-diethylimidazole and 7.40 g (45.2mmol) of methyl triflate, there was obtained 12.38 g of 1,2-Et 2-3-MeIm + TfO - (95%). 1H-NMR (acetone-d 3, δ/ppm relative to TMS):7.68 (d, 1H, J ) 2.5 Hz), 7.63 (d, 1H, J ) 2.5 Hz), 4.37 (q, 2H, J )9.0 Hz), 3.24 (q, 2H, J ) 9.5 Hz), 1.53 (t, 3H, J ) 9.0 Hz), 1.36 (t,3H, J ) 9.0 Hz).1-Ethyl-3-methylimidazolium Nonafluorobutanesulfonate (EtMe-Im + NfO - ). A 19.10 g (0.10 mol) sample of EtMeIm + Br - in 50 mLof H 2O and 33.80 g (0.10 mol) of potassium nonafluorobutanesulfonate(Fluka, purum), in 100 mL of H 2Oat70°C were mixed. The solutionwas extracted by 100 mL of CH 2Cl 2, and the extract was concentratedand dried 2hat60°C under 0.1 mbar of pressure to afford 24.4 g ofEtMeIm + NfO - (59%) free of Br - (no precipitate with AgNO 3). Furtherextractions gave a salt that produced a precipitate with AgNO 3. 1H-NMR (0.139 M in acetone-d 3, δ/ppm relative to TMS): identical toEtMeIm + TfO - .1-Butyl-3-methylimidazolium Nonafluorobutanesulfonate (BuMe-Im + NfO - ). A solution of 9.54 g (43.5 mmol) of BuMeIm + Br - in 50mL of H 2O and a solution of 14.16 g (41.9 mmol) of KNfO in 100 mLof H 2Oat70°C were mixed under stirring. After decantation, theliquid salt was washed twice with 30 mL H 2O and dried 2hat150°Cunder 0.1 mbar of pressure to afford 14.40 g of BuMeIm + NfO - (78%).Anal. Calcd for C 12H 15N 2O 3F 9S: C, 32.88; H, 3.45; N, 6.39; O, 10.95;F, 39.01; S, 7.31. Found: C, 32.21/32.08; H, 3.65/3.42; N, 6.53/6.10;O, 12.1; F, 38.37. 1H-NMR (acetone-d 3, δ/ppm relative to TMS):identical to BuMeIm + TfO - .1,3-Dimethylimidazolium Bis((trifluoromethyl)sulfonyl)amide(Me 2Im + Tf 2N - ). Same procedure as for EtMeIm + NfO - . From 6.02g (27.0 mmol) of Me 2Im + I - and 7.75 g (27.0 mmol) of lithium bis-((trifluoromethyl)sulfonyl)amide (3M or Fluka, puriss.), there wasobtained 6.08 g of Me 2Im + Tf 2N - (60%). Anal. Calcd forC 7H 9N 3O 4F 6S 2: C, 22.29; H, 2.40; N, 11.14; O, 16.96; F, 30.21; S,17.00. Found: C, 22.33; H, 2.30; N, 11.04; O, 17.3; S, 16.97. 1H-NMR (acetone-d 3, δ/ppm relative to TMS): 8.94 (s, 1H), rest identicalto Me 2Im + TfO - .1-Ethyl-3-methylimidazolium Bis((trifluoromethyl)sulfonyl)amide(EtMeIm + Tf 2N - ). The same procedure was used as for Me 2Im + Tf 2N - .From 20.54 g (107 mmol) of EtMeIm + Br - and 30.85 g (107 mmol) ofLiTf 2N, there was obtained 35.11 g of EtMeIm + Tf 2N - (84%). Anal.Calcd for C 8H 11N 3O 4F 6S 2: C, 24.56; H, 2.83; N, 10.74; O, 16.35; F,29.13; S, 16.39. Found: C, 24.38; H, 2.74; N, 10.64; O, 16.8; S, 16.75,Li,