4-(4-Nitrobenzyl)pyridinium 3-carboxy-4-hydroxybenzenesulfonate

Abstract

In the title salt, C12H11N2O2+·C7H5O6S−, the dihedral angle between the benzene and pyridine rings in the 4-(4-nitrobenzyl)pyridinium cation is 82.7 (2)°. Within the anion there is an intramolecular hydroxy-O—H...O(carboxylic acid) bond. In the crystal, the cation forms a single N+—H...Osulfonate hydrogen bond with the anion. These cation–anion pairs interact through duplex anion carboxylic acid O—H...Osulfonate hydrogen bonds, giving a centrosymmetric cyclic association [graph set R22(16)]. The crystals studied were non-merohedrally twinned.