Reaction Steps
The complex 1-(butyl)-3-(3-triethoxysilylpropyl)-4,5-dihydroimidazolium chloride (2) (10 g, 28.0 mmol) was dissolved in acetonitrile (200 ml) and treated with one equivalent of sodium tetrafluoroborate (3.1 g, 28.0 mmol). The resulting slurry was stirred for 5 days at room temperature. After the removal of the precipitate by filtration the volatiles were evaporated under reduced pressure (10−2 torr) to give a brown liquid of complex (3) in 99% yield. 1H NMR (CD3CN) 0.50 (m, 2H, 3J=7.0, CH2—CH2—Si), 0.86 (tr, 3H, 3J=7.4, —CH2—CH2—CH3), 1.11 (tr, 9H, 3J=7.0, CH3—CH2—O), 1.26 (six, 2H, 3J=7.4, —CH2—CH2—CH3), 1.54 (m, 2H, Si—CH2—CH2—), 1.62 (m, 2H, —CH2—CH2—CH3), 3.38 (m, 4H, Si—CH2—CH2—CH2—N and —N—CH2—CH2—N—Bu), 3.72 (qr, 6H, CH3—CH2—O), 4.84 (m, 4H, —N—CH2—CH2—CH2—CH3 and —N—CH2—CH2—N—Bu), 8.20 (s, 1H, N—CH—N) ppm; 13C NMR (CD3CN) 8.47 (1C, Si—CH2—CH2—)−, 14.81 (1C, —CH2—CH2—CH3), 19.53 (3C, CH3—CH2—O—), 20.98 (1C, —CH2—CH2—CH3), 22.44 (1C, Si—CH2—CH2—), 30.54 (1C, —CH2—CH2—CH3), 49.09, 49.73, 49.89, 51.58 (4C, —CH2—N—CH2—CH2—N—CH2—), 59.90 (3C, CH3—CH2—O—), 159.09 (1C, N—CH—N) ppm; FT-IR (KBr) 3087 w, 2973 s, 2929 s, 2880 s, 1658 s, 1524 m, 1449 m, 1388 s, 1303 m, 1255 m, 1080 br, 957 m, 787 s cm−1; MS/ES+ (m/e) 331 [M+]. Anal. Calcd. for C16H35N2BF4O3Si: C, 45.94; H, 8.43; N, 6.70; B, 2.58; F, 18.16. Found: C, 45.95; H, 8.52; N, 7.34; B, 2.24; F, 17.86.
