2-amino-6-methylpyridinium 4-methylbenzenesulfonate

Abstract

In the asymmetric unit of the title salt, C6H9N 2+·C7H7O3S -, there are two independent 2-amino-6-methylpyridinium cations and two independent 4-methylbenzenesulfonate anions. Both cations are protonated at their pyridine N atoms and their geometries reveal amine-imine tautomerism. In the 4-methylbenzenesulfonate anions, the carboxylate groups are twisted out of the benzene ring planes by 88.4(1) and 86.2(2)°. In the crystal, the sulfonate O atoms of an anion interact with the protonated N atoms and the 2-amino groups of a cation via a pair of N - H⋯O hydrogen bonds, forming an R22(8) ring motif. These motifs are connected via N - H⋯O hydrogen bonds, forming chains running along the a-axis direction. Within the chains there are weak C - H⋯O hydrogen bonds present. In addition, aromatic π-π stacking interactions [centroid-centroid distances = 3.771(2), 3.599(2), 3.599(2) and 3.497(2)Å] involving neighbouring chains are also observed. © 2014 CrossMark.