Seven crystal structures of pyromellitic acid or trimesic acid salts of molecules that contain pyridine and amide functionalities were determined and their structures were analyzed in detail in terms of various intermolecular interactions. The presence of multiple functionalities (acid, pyridine, amide, and hydroxy groups) in these structures resulted in diversified supramolecular architectures. Amide-to-amide hydrogen bonds are not observed in any of these structures because of interference by the anions, water molecules, or pyridinium cations. The symmetry of the components was found to be important in determining the resultant supramolecular synthon and, therefore, the overall architecture. The pyromellitate anions exhibited four types of geometries which, differ in valencies and intramolecular hydrogen bonding, and these anions also exhibit self stacks when they have planar geometries.
Comparison of the polymorphs and solvates of two analogous fungicides—a case study of the applicability of a supramolecular synthon approach in crystal engineering
