Synthesis and physical properties of tris(dialkylamino)cyclopropenium dicyanamide ionic liquids

The synthesis and properties of 16 tris(dialkylamino)cyclopropenium (TDAC) cations with the dicyanamide (DCA) anion, [N(CN)(2)](−), are described. D(3h)- and C(3h)-symmetric cations ([C(3)(NR(2))(3)]DCA (R = Me, Et, Pr, Bu, Pent, Hex, Dec) and [C(3)(NRMe)(3)]DCA (R = Bu, St), respectively) were synthesised by reaction of C(3)Cl(5)H with the corresponding amine. Reaction of the alkoxydiaminocyclopropenium salt [C(3)(NEt(2))(2)(OMe)](+) with amines led to a series of C(2v)-symmetric salts [C(3)(NEt(2))(2)(NR(2))]DCA (R = Me, Bu, Hex) and two C(s)-symmetric salts and [C(3)(NEt(2))(2)(NRMe)]DCA (R = Me, Bu). Similarly, [C(3)(NMe(2))(2)(OMe)](+), was used to prepare the C(s)-symmetric salts [C(3)(NMe(2))(2)(NRMe)]DCA (R = Pr, Bu). In addition to characterisation by NMR, mass spectrometry and microanalysis, the salts were characterised by DSC, TGA, density, viscosity, conductivity and miscibility/solubility studies. Comparisons have been made with similar series of bistriflimide (NTf(2)(−)) salts that have been previously reported to see whether the same trends are observed with a different anion.