The synthesis, structure, and bonding of
alkali salts of resonance stabilized
amides, such as diformylamide (dfa), formylcyanoamide (fca), nitrocyanoamide (nca), and for comparision, the well-known dicyanoamide (dca), are discussed on the basis of experimental and theoretical data. The first structural reports of K(18-crown-6)+dfa-, K(18-crown-6)+fca-, Na+nca-, and Li(
TMEDA)+dca- are presented. Examination of the X-ray data reveals almost planar
anions with strong
cation-
anion interactions resulting in network-like structures in the solid state. For comparison, the X-ray structures of covalently bound phenyldicyanoamide and diformamide are also discussed. The thermal behavior of the
alkali salts of these
amides is studied by thermoanalytical experiments. Moreover, several novel
ionic liquids based on resonance stabilized
amides have been prepared and were fully characterized, namely the dfa, fca, and nca
salts of EMIM (1-ethyl-3-methyl-imidazolium), BMIM (1-butyl-3-methyl-imidazolium), and HMIM (1-hexyl-3-methyl-imidazolium). Most of them are liquid at room temperature, except BMIM+fca- that melts at 32 degrees C. These
ionic liquids are neither heat nor
shock sensitive, are thermally stable up to over 200 degrees C, and can be prepared easily in large quantities.