XI. Synthetic procedures NMR Characterization. 400 MHz 1H, 100 MHz 13C, and 376 MHz 19F NMR spectra were recorded on a Bruker Avance III 400 NMR spectrometer in CD3CN. Solvent residual signals with chemical shifts of 1.94 ppm (1H NMR) and 118.69 ppm (13C NMR) were used as references. 1-Isopropyl-3-propylimidazolium iodide. A 250 mL round bottom flask equipped with a magnetic stirring bar and reflux condenser was charged with 1-isopropylimidazole (5.185 g, 47.0 mmol) and NaHCO3 (1.5 eq., 70.5 mmol, 5.92 g). Acetonitrile (100 mL) and 1iodopropane (2 eq., 94 mmol, 16.0 g, 9.2 mL) were added and the mixture was stirred at 50 °C for 1 week under N2. Acetonitrile was removed under vacuum and the residue was dissolved in CH2Cl2 (50 mL). The CH2Cl2 solution was separated from the formed salts which were subsequently washed with some CH2Cl2. Under stirring, diethyl ether (150 mL) was added to the combined CH2Cl2 solutions under stirring to precipitate the imidazolium iodide product. The flask was placed in a refrigerator overnight. The CH2Cl2/ether layer was removed and the liquid residue was washed with diethyl ether (50 mL) which was also removed. The residue was dried under a slow flow of N2 and subsequently under vacuum (6 mbar, then 0.01 mbar), yielding 1-isopropyl-3-propylimidazolium iodide as a colorless liquid (12.77 g, 97%). 1H NMR (CD3CN, 400 MHz): (ppm) = 0.90 (t, CH3, 3H), 1.52 (d, CH3, 6H), 1.88 (m, CH2, 2H), 4.17 (t, N-CH2, 2H), 4.66 (m, CH, 1H), 7.51 (s, H-4 or H-5, 1H), 7.57 (s, H-4 or H-5, 1H), 9.23 (H-2, s, 1H). 13C NMR (CD3CN, 100 MHz): (ppm) = 11.31 (CH2CH3), 23.58 (CH3), 24.51 (CH2), 52.07 (N-CH2), 54.19 (CH), 121.99 (C-4 or C-5), 123.75 (C-4 or C-5), 136.29 (C-2). Counterion exchange. The following procedure was used to convert 1-isopropyl-3propylimidazolium iodide, 1,3-diisopropylimidazolium chloride and 1,3-di-tertbutylimidazolium tetrafluoroborate into the corresponding NTf2 salts. The imidazolium iodide, chloride, or tetrafluoroborate (18.65 mmol) was dissolved in CH3CN (20 mL). To this solution, Li NTf2 (20.52 mmol, 1.1 eq.) was added as a solid. Milli-Q water (20 mL) was added and the
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