Crystal engineering of organic clay mimics from 3,5-pyrazoledicarboxylic acid and amines.

The syntheses and crystal structures of sixteen compounds containing the monoanion of 3,5-pyrazoledicarboxylic acid (H(2)PzDCA) and ammonium-based counterions are reported. The cations contain short-chain alkyl, long-chain alkyl, phenyl, and chloro-, methoxy-, and amine-substituted aryl groups. Self-complementary HPzDCA intermolecular hydrogen bonds create nearly planar sheets, to which the cations connect through hydrogen bonds.