The reaction of nickel(II) nitrate hexahydrate, propane-1,2- diamine and pyridine-2,6-dicarboxylic acid in a 1:2:2 molar ratio in aqueous solution resulted in the formation of the title compound, (C3H12N2)[Ni(C7H3NO4)2]4H2O or (p-1,2-daH2)- [Ni(pydc)2]4H2O (where p-1,2-da is propane-1,2-diamine and pydcH2 is pyridine-2,6-dicarboxylic acid). The geometry of the resulting NiN2O4 coordination can be described as distorted octahedral. Considerable C O stacking interactions are observed between the carboxylate C O groups and the pyridine rings of the (pydc)2 fragments, with O distances of 3.1563 (12) and 3.2523 (12) A ° and C O angles of 95.14 (8) and 94.64 (8). In the crystal structure, a wide range of non-covalent interactions, consisting of hydrogen bonding [O—H O, N—H O and C—H O, with D A distances ranging from 2.712 (2) to 3.484 (2) A ° ], ion pairing, – [centroid-to-centroid distance = 3.4825 (8) A ° ] and C O stacking, connect the various components to form a supramolecular structure.
