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.