Syntheses of 1-alkyl-1,2,4-triazoles and the formation of quaternary 1-alkyl-4-polyfluoroalkyl-1,2,4-triazolium salts leading to ionic liquids

1,2,4-Triazole was alkylated (alkyl = methyl, butyl, heptyl, decyl) at N-1 in > 90% isolated yields. The resulting 1-alkyl triazoles were quaternized at N-4 in > 98% isolated yields using fluorinated alkyl halides with > 98% isolated yields, under neat reaction conditions at 100-120 degreesC to form N1-CH2-N4-(CH2)(2)CmF2m (divided by 1)-triazolium (Taz) iodide (m = 1, 6), N1-C4H9-N4-(CH2)(2)CmF2m (+ 1)-Taz iodide (m = 1, 4, 6), N1-C7H15-N4-(CH2)(2)CmF2m + 1-Taz iodide (m = 1, 4, 6), NI-C10H21-N4-(CH2)(2)CmF2m (+ 1)-Taz iodide (m = 1, 4), and N1-CnH2n (divided by 1)-N4-(CH2)(2)F-Taz bromide (n = 4, 7, 10). Single-crystal X-ray analyses confirmed the structure of [1-CH3-4-CH2CH2CF3-Taz]I-+(-). It crystallized in the orthorhombic space group Pccn, and the unit cell dimensions were a = 13.8289(9) Angstrom, b = 17.3603-(11) Angstrom, c = 9.0587(6) Angstrom (alpha = beta = gamma = 90degrees). Metathesis of these polyfluoroalkyl-substituted triazolium halides with other salts led to the formation of quaternary compounds, some of which comprise ionic liquids, namely, [R(R-f)-Taz]Y-divided by(-) (Y = NTf2, BF4, PF6, and OTf), in good isolated yields without the need for further purification: N1-CH3-N4-(CH2)(2)CmF2m (+) (1)-Taz Y (m = 1, 6; Y = NTf2), N1-C4H9-N4-(CH2)(2)CmF2m (divided by) (1)-Taz Y (m = 1, 4, 6; Y = NTf2), N1-C7H15-N4-(CH2)(2)CmF2m (+ 1)-Taz Y (m = 1, 4, 6; Y = NTf2), N1-C10H21-N4-(CH2)(2)CmF2m (+ 1)-Taz Y (n = 1, 4; Y = NTf2), N1-CnH2n (+ 1)-N4-(CH2)(2)F-Taz Y (n = 7, 10; Y = NTf2), N1-C10H21-N4-(CH2)(2)F-TazY (Y = OTf), N1-C7H15-N4-(CH2)(2)F-TazY (Y = BF4), N1-C4H9-N4-(CH2)(2)C(m)F2(m) (+ 1)-Taz Y (m 4, 6; Y PF6) N1-C7H15-N4-(CH2)(2)C4F9-Taz Y (Y = PF6) N1-C4H9-N4-(CH2)(2)C(m)F2(m) (+ 1)-Taz Y (m 4, 6; Y = OTf). All new compounds were characterized by H-1, F-19, and C-13 NMR and MS spectra and elemental analyses. T(g)s and T(m)s of ionic liquids were determined by DSC.