Bis(dimethylammonium) 3,3′-dicarboxy-5,5′-(5,7,12,14-tetraoxo-6,13-diazatetracyclo[6.6.2.04,16.011,15]hexadeca-1,3,8,10,15-pentaene-6,13-diyl)dibenzoate dihydrate

The title compound, 2C2H8N+·C30H12N2O122−·2H2O, comprises dimethylammonium cations, 3,3′-dicarboxy-5,5′-(5,7,12,14-tetraoxo-6,13-diazatetracyclo[6.6.2.04,16.011,15]hexadeca-1,3,8,10,15-pentaene-6,13-diyl)dibenzoate dianions and water molecules. The dianion is situated on a crystallographic inversion centre. Two very strong symmetry-restricted O...H...O hydrogen bonds are present which are situated about the crystallographic inversion centres. In one of these hydrogen bonds, the H atom is situated at its centre, while in the other one the H atom is disordered about its centre. Both H atoms are involved in the chain-like C22(16) motif, and not in a more common motif R22(8) that is composed of a pair of hydrogen carboxylates with the H atoms situated about the centre between the pair of O atoms. In the crystal, interaction of these hydrogen bonds results in formation of anionic layers of dianions parallel to (-111). The water molecules donate their H atoms to one of two of the carboxylate O atoms, forming strong hydrogen bonds. The dimethylammonium donates a bifurcated hydrogen bond to an oxo group of the dianion, forming weak hydrogen bonds. All the hydrogen bonds form a three-dimensional hydrogen-bonded network.