4,4′-Iminodipyridinium bis(hydrogen phthalate)

Abstract

In the title salt, C10H11N32+·2C8H5O4−, doubly protonated 4,4′-dipyridylamine (dpa) cations participate in N—H...O hydrogen bonding with two hydrogen phthalate anions to form a neutral unit. Both anions contain an intramolecular O—H...O hydrogen bond. In the crystal structure, these units form two-dimensional layers through π–π stacking interactions with a centroid-to-centroid distance of 3.763 (3) Å. In turn, these layers aggregate in three dimensions by additional N—H...O hydrogen bonding. The assignment to the noncentrosymmetric space group P1 is corroborated by chemically unreasonable aromatic ring bond distances and poor K scale factor distributions for a disordered model in the centrosymmetric Poverline{1} space group.