Abstract
Pyridazine (1a), pyrazine (1b), pyrimidine (1c) and 1,4-dimethylpiperazine (1d) were quaternized at N-1 with alkyl iodides and polyfluoroalkyl halides under either
neat or solvent conditions at 10-110 °C to form N1CH2CH2CmF2m+1 (m = 0, 1, 6, 10) diazinium iodides, and N1CH2CH2F diazinium bromides in moderate to excellent isolated yields. Metathesis of these
alkyl and monopolyfluoroalkyl substituted diazinium halides with other salts led to
the formation of new quaternary compounds, some of which fall into the ionic liquid
class (mp <100 °C), where [N1(RfCH2CH2)+]Y- (Y = NTf2, PF6, OTf, NO3, ClO4). 1,4-Dimethylpiperazine with 2.5 equivalents of 1-bromo-2-fluoroethane in DMSO gave
the diquaternized N1, N4-(CH2CH2F)2 product. All compounds were characterized by 1H, 13C, 19F NMR, MS, elemental analyses, and density measurements (for liquids). The phase transition
and decomposition temperatures of the quaternized compounds were determined by DSC.
Key words
quaternization - ionic liquids - diazine - fluoroalkyl - polyfluoroalkyl
