**2. Materials and physical measurements**

Analytical grade chemicals were used for synthesis without further purification. 1-ethyl imidazole, 2-bromoethylamine hydrobromide, 5-nitro-2-hydroxybenzaldehyde and NaBF4 (sodium tetrafluoroborate) were purchased from Sigma Aldrich, Germany. Metal acetates and other reagents were used as obtained from SD Fine Chemicals, India. CH3OH, petroleum ether, CHCl3, DMF and DMSO were used after purification by standard methods described in the literature. FT-IR spectra were recorded by KBr pellets on a Perkin-Elmer Spectrum FT-IR spectrometer (RX-1). 1 H NMR and 13C NMR spectra were recorded on a FT-NMR (Bruker Avance-II 400 MHz) spectrometer by using D2O and DMSO-*d*6 as solvents. Powder X-ray diffraction (XRD) data were obtained on INEL XRD Model Equinox 1000 using Cu Kα radiation (2*θ* = 0–90°). Elemental microanalysis (CHN analysis) was performed on Perkin-Elmer (Model 240C) analyzer. Metal content was obtained from AAS (Varian, SpectrAA 50B) by using standard metal solutions procured from Sigma-Aldrich, Germany. ESI-MS spectra were obtained on a JMS-T100LC spectrometer. The purity of the synthesized products was confirmed by thin layer chromatography (TLC) Merck 60 F254 silica gel plates (layer thickness 0.25 mm) and the spots were visualized using UV-light. The UV-visible spectra were obtained from JascoV-530 double beam spectrophotometer using CH3OH as solvent. Specific conductance was measured at (298.15 ± 0.01) K with a Systronic conductivity TDS-308 metre. Magnetic susceptibility was measured with a Sherwood Scientific Ltd. magnetic susceptibility balance (Magway MSB Mk1) at ambient temperature. The melting point of synthesized compounds was determined by open capillary method. Antibacterial activity (*in vitro*) of the synthesized ligand and complexes were evaluated by well diffusion method against six bacterial strains (two Gram-positive and four Gramnegative). The bacterial strains were obtained from MTCC, Chandigarh, India.

**83**

*Imidazolium Ionic Liquid-Supported Schiff Base and Its Transition Metal Complexes: Synthesis…*

The FIL was synthesized by following a literature procedure [25]. [2-aeeim]BF4

NMR (400 MHz, D2O): δ = 3.63 (m, 2H, NH2▬CH2), 4.16 (s, 3H, CH3), 4.49 (t, 1H,

5-nitro-2-hydroxybenzaldehyde (1.67 g, 10 mmol) and [2-aeeim]BF4 (2.27 g, 10 mmol) were taken in methanol and stirred at 25°C for 4 h. After completion of reaction, the product was diluted using ethanol. The precipitate was filtered, washed with cold EtOH and dried properly to collect the expected ligand as a yel-

TMS): *δ* = 3.36 (q, 2H, N▬CH2), 3.60 (s, 3H, CH3), 3.92 (t, 2H, N▬CH2), 4.60 (t, 2H, N▬CH2), 7.44 (s, 1H, NCH), 7.52 (s, 1H, NCH), 7.53 (s, 1H, N═CH), 7.61–7.59 (m, 3H, Ar-H), 8.65 (s, 1H, N(H)CN), 8.88 (s, 1H, OH). 13C NMR: (400 MHz, DMSO-*d*6, TMS): *δ* = 159.76, 138.43, 134.08, 130.47, 130.31, 123.89, 119.80, 118.65, 110.65, 39.86, 39.65, 39.24, 39.03 and 38.82. IR (KBr): ʋ = 3448 (O▬H), 3071, 1664 (C═N), 1343 (N▬O), 1293 (C▬O), 1095 (B▬F). UV/vis (methanol, λmax): 206,

+

289. Anal. calcd. for C14H17N4O3BF4 (376): C 44.71, H 4.56, N 14.90. found: C 44.64,

To an ethanolic solution of ligand, LH (2c) (0.376 g, 1 mmol) in round bottomed

Brown solid; (0.54 g, 67%), decomposes at ~293°C. IR (KBr): ʋ = 3386 (O▬H), 1648 (C═N), 1332 (N▬O), 1177 (C▬O), 1106 (B▬F), 651 (M▬O), 510 (M▬N). UV/vis (methanol, λmax/nm): 227, 246, 358. ESI-MS (CH3OH, *m/z*) [M-2BF4]

Light green solid; (0.56 g, 69%), decomposes at ~293°C. IR (KBr): ʋ = 3396 (O▬H),

1637 (C═N), 1330 (N▬O), 1172 (C▬O), 1102 (B▬F), 646 (M▬O), 526 (M▬N).

41.56, H 3.99, N 13.85, Co 7.28, found: C 41.36, H 3.71, N 13.55, Co 7.12.

: 635, found: 635; anal. calcd. for C28H36CoB2F8N8O8 (809): C

flask, metal acetate salt Co(II), Ni(II) and Cu(II), *viz.*, (0.5 mmol) dissolved in ethanol was added and the reaction mixture was refluxed for 12 h until the starting materials were completely consumed as monitored by TLC. On completion of the reaction, solvents were evaporated and the reaction mixture was cooled to room temperature. The precipitate was collected by filtration, washed successively with cold ethanol (10 mL × 3). Finally it was dried in vacuum desiccators to obtain the solid product. The complexes were soluble in *N*,*N*-dimethylformamide, dimethylsulfoxide, acetonitrile, methanol and water. A schematic representation of the

calcd. for [C14H17N4O3]

: 140, found: 140 [M-BF4]

H NMR (400 MHz, D2O, TMS): *δ* = 1

+

H NMR: (400 MHz, DMSO-*d*6,

+

: 289, found;

+ calcd.

H

. Anal. calcd. for

**2.1 Synthesis of 1-(2-aminoethyl)-3-ethylimidazolium tetrafluoroborate** 

N▬CH2), 4.56 (t, 1H, N▬CH2), 7.40 (s, 1H, NCH), 7.50 (s, 1H, NCH), 8.61 (s, 2H, NH2), 8.87 (s, 1H, N(H)CN); IR (KBr): ʋ = 3447, 3086, 2896, 1626, 1452,

+

**2.2 Synthesis of imidazolium ionic liquid-supported Schiff base, LH (2a)**

C7H14F4N3B: C 37.04, H 6.22, N 18.51, found: C 36.99, H 6.14, N 18.43.

*DOI: http://dx.doi.org/10.5772/intechopen.86379*

was obtained as yellow oil; (98 mg, 70%); <sup>1</sup>

lowish brown solid; (282 mg, 75%). mp. 95–97°C. <sup>1</sup>

234, 306 nm; ESI-MS (CH3OH, *m/z*) [M-BF4]

**2.3 Synthesis of the metal complexes (3a, 4a and 5a)**

H 4.49, N 14.83.

syntheses is given in **Figure 1**.

+

*2.3.1 Co(II)complex (3a)*

for [C28H32CoN8O6]

*2.3.2 Ni(II)complex (4a)*

1084. ESI-MS (*m/z*) calc for [C7H14N3]

**[2-aeeim]BF4 (1a)**

*Imidazolium Ionic Liquid-Supported Schiff Base and Its Transition Metal Complexes: Synthesis… DOI: http://dx.doi.org/10.5772/intechopen.86379*
