Supramolecular patterns and Hirshfeld surface analysis in the crystal structure of bis(2-amino-4-methoxy-6-methylpyrimidinium) isophthalate

In the title molecular salt, 2C 6 H 10 N 3 O + ·C 8 H 4 O 4 2− , the N atom of each of the two 2-amino-4-methoxy-6-methylpyrimidine molecules lying between the amine and methyl groups has been protonated. The dihedral angles between the pyrimidine rings of the cations and the benzene ring of the succinate dianion are 5.04 (8) and 7.95 (8)°. Each of the cations is linked to the anion through a pair of N—H...O(carboxylate) hydrogen bonds, forming cyclic R 2 2 (8) ring motifs which are then linked through inversion-related N—H...O hydrogen bonds, giving a central R 2 4 (8) motif. Peripheral amine N—H...O hydrogen-bonding interactions on either side of the succinate anion, also through centrosymmetric R 2 2 (8) extensions, form one-dimensional ribbons extending along [211]. The crystal structure also features π–π stacking interactions between the aromatic rings of the pyrimidine cations [minimum ring centroid separation = 3.6337 (9) Å]. The intermolecular interactions were also investigated using Hirshfeld surface studies and two-dimensional fingerprint images.