All ligands (except #3) were synthesized with reference to the modified Starikova et al. method [20]. Typical generic synthesis steps are given below with spectral and analytical data. N-monosubstituted imidazole (0.1 mmol) and anhydrous toluene were added to a two-necked flask and stirred until a homogeneous solution was formed; followed by the slow dropwise addition of ethyl bromide (0.3 mmol) under continuous stirring. After the dropwise addition, the reaction mixture was heated with stirring at 40 °C for 24 hours. After completion of the reaction, the solvent was removed under reduced pressure and the resulting product was dried under vacuum to give the target ligand.2.2.2 1-Ethyl-3-methylimidazolium bromide (2) was a white solid with a yield of 4.70 g (98% yield).IR (ATR, cm?1): 3065, 2975, 1670, 1571, 1467, 1172, 1101, 856, 789, 649, 621, 417. 649, 621, 417; 1H NMR (400 MHz, CDCl3): δ 1.47 (3H, t, J = 7.3 Hz, CH3), 3.97 (3H, s, NCH3), 4.32 (2H, q, NCH2), 7.54 (2H, s, NCH), 10.07 (1H, s, CH); 13C NMR (100 MHz, CDCl3): δ 15.64 (CH3), 36.63 (NCH3), 45.18 (NCH2), 122.01 (NCH), 123.71 (NCH), 136.73 (NCH). Mass spectrum (ESI): m/z 111.5 (M+?Br?). High-resolution mass spectrum (ESI): calculated value C6H11BrN2 (M+?Br?) 111.09222, measured value 111.09196.
