## 2 Materials and Methods
### Chemical Synthesis  
2.1 Synthesis of (S)-3-(but-3-en-1-yl)-1-(1-(butylamino)-3-methyl-1-oxobutan-2-yl)-1H-imidazol-3-ium bromide 3  
Synthesis of (S)-3-(but-3-en-1-yl)-1-(1-(butylamino)-3-methyl-1-oxobutan-2-yl)-1H-imidazol-3-ium bromide 3 (Scheme 1).  
Figure 1: Silica capillaries coated with cross-linked polymeric ionic liquids (PILs).  
Compound **2** (0.10 g, 4.43 \(\times\) 10\({}^{-4}\) mol, 1 equivalent), obtained as previously described [46], and 4-bromo-1-butene (0.93 mL, 4.43 \(\times\) 10\({}^{-4}\) mol, 10 equivalents) were dissolved in dry acetonitrile (1 mL) in a round-bottom flask (25 mL). The reaction mixture was stirred and heated at 60 \({}^{\circ}\)C for 24 h under a N\({}_{2}\) atmosphere. The solvent was evaporated under reduced pressure and the resulting crude residue was washed with hexane:ether (2:1), affording compound **3** as a yellow oil (0.0775 g, 47.2%). M.p. 9 \({}^{\circ}\)C. [\(\alpha\)]\({}_{\mathrm{D}}^{25}\) = +27.64 (c = 0.033, MeOH). IR (ATR): \(\gamma_{\mathrm{max}}\) = 3413, 3227, 3068, 2962, 2933, 2872, 1673, 1550, 1463, 1159 cm\({}^{-1}\). \({}^{1}\)H NMR (CDCl\({}_{3}\)) \(\delta\) = 9.84 (s, 1H), 8.55 (s, 1H), 7.77 (s, 1H), 7.15 (s, 1H), 5.80-5.62 (m, 2H), 5.17-4.94 (m, 2H), 4.33-4.17 (m, 2H), 3.31-3.20 (m, 1H), 3.15-3.03 (m, 1H), 2.70-2.54 (m, 2H), 2.46-2.34 (m, 1H), 1.58-1.41 (m, 2H), 1.38-1.22 (m, 2H), 1.03 (d, \(J\) = 6.6 Hz, 3H), 0.83 (t, \(J\) = 7.3 Hz, 3H), 0.73 (d, \(J\) = 6.7 Hz, 3H). \({}^{13}\)C NMR (CDCl\({}_{3}\)): \(\delta\) = 167.0, 136.1, 131.5, 121.6, 121.0, 120.3, 67.6, 49.5, 39.6, 34.2, 31.3, 31.0, 20.2, 18.7, 18.2, 13.6 ppm. MS (ESI+): 278.4 [M + H\({}^{+}\), 100]. C\({}_{16}\)H\({}_{28}\)BrN\({}_{3}\)O-1.5 H\({}_{2}\)O: calcd. C 53.63, H 7.88, N 11.73; found C 53.16, H 8.04, N 11.17.  
Synthesis of (S)-3-(but-3-en-1-yl)-1-(1-(butylamino)-3-methyl-1-oxobutan-2-yl)-1H-imidazol-3-ium trifamide 4 (Scheme 1).  
Compound **3** (0.12 g, 2.76 \(\times\) 10\({}^{-4}\) mol, 1 equivalent) and lithium bis((trifluoromethyl)sulfonyl)amide (0.09 g, 2.76 \(\times\) 10\({}^{-4}\) mol, 1.1 equivalents) were dissolved in methanol in a round-bottom flask (50 mL). The reaction mixture was stirred at room temperature for 24 h. The solvent was evaporated under reduced pressure and the resulting crude residue was extracted with CH\({}_{2}\)Cl\({}_{2}\) (3\(\times\)), dried with anhydrous MgSO\({}_{4}\), filtered, and concentrated, leading to compound **4** as a yellow oil (0.10 g, 62.45%). M.p. - 36 \({}^{\circ}\)C. [\(\alpha\)]\({}_{\mathrm{D}}^{25}\) = +23.15 (c = 0.034, MeOH). IR (ATR): \(\gamma_{\mathrm{max}}\) = 3381, 3147, 3111, 2966, 2938, 2876, 1677, 1548, 1348, 1184, 1134, 1053 cm\({}^{-1}\). \({}^{1}\)H NMR (CDCl\({}_{3}\)) \(\delta\) = 8.95 (s, 1H), 7.74 (s, 1H), 7.11 (s, 1H), 7.08 (s, 1H), 5.73-5.66 (m, 1H), 5.08 (d, \(J\) = 10.2 Hz, 1H), 4.97 (d, \(J\) = 17.1 Hz, 1H), 4.65 (d, \(J\) = 10.4 Hz, 1H), 4.30-4.08 (m, 2H), 3.27-3.19 (m, 1H), 3.16-3.03 (m, 1H), 2.68-2.44 (m, 2H), 2.39-2.21 (m, 1H), 1.46-1.39 (m, 2H), 1.33-1.20 (m, 2H), 1.00 (d, \(J\) = 6.6 Hz, 3H), 0.87-0.79 (m, 3H), 0.69 (d, \(J\) = 6.7 Hz, 3H).\({}^{13}\)C NMR (CDCl\({}_{3}\)): \(\delta\) = 166.5, 135.5, 131.5, 123.6, 122.0, 121.5, 121.0, 120.3, 118.5, 115.9, 68.7, 49.5, 39.7, 34.3, 32.3, 30.8, 19.9, 18.6, 18.0, 13.5 ppm. MS (ESI+): 278.4 [M+H\({}^{+}\), 100]. MS (ESI-): m/z (%) = 280.2 [NTf\({}_{2}\)-, 100]. C\({}_{18}\)H\({}_{28}\)F\({}_{6}\)N\({}_{4}\)O\({}_{5}\)S\({}_{2}\): calcd. C 38.71, H 5.05, N 10.03, S 11.48; found C 39.07, H 5.31, N 9.70, S 11.03.