Different spatial arrangements in the 4-nitrophthalic acid salts

The crystal structure of three salts of 4-nitrophthalic acid with pyridine (1), 2-amino pyridine (2) and with 8-aminoquinoline (3) are determined. The role of weak and strong hydrogen bonding in crystal packing is ascertained. It is observed that the orientation of the 4-nitrophthalic acid in the lattice is governed by the hydrogen bonding; either sheet-like structure or helical chain can be constructed based on the amine under consideration.