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The syntheses and crystal structures of sixteen compounds containing the monoanion of 3,5-pyrazoledicarboxylic acid (H2PzDCA) 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. Twelve of the structures exhibit virtually identical hydrogen-bonded layers, but the distance between layers varies from 9.33 to 14.10 A (±20 %), depending on the cation. The comparison of the sixteen structures leads to the identification of a building block (HPzDCA) that creates remarkably reproducible, lamellar structures despite substantial changes in the counterion.

The crystal engineering of hydrogen bonded coordination complexes is reviewed. The emphasis is on coordination complexes with peripheral hydrogen bonding substituents. Structures with one-, two- and three-dimensional networks, as well as combinations of coordination polymers and hydrogen bonds, are reported.