2-[(E)-2-(4-Hydroxy-3-methoxyphenyl)ethenyl]-1-methylpyridinium 4-bromobenzenesulfonate monohydrate

Abstract

The title salt crystallized as the monohydrate C15H16NO2+·C6H4BrSO3−·H2O. The cation exists in an E conformation with respect to the ethynyl bond and is essentially planar, with a dihedral angle of 6.52 (14)° between the pyridinium and the benzene rings. The hydroxy and methoxy substituents are coplanar with the benzene ring to which they are attached, with an r.m.s. deviation of 0.0116 (3) Å for the nine non-H atoms [Cmethyl—O—C—C torsion angle = −0.8 (4)°]. In the crystal, the cations and anions are stacked by π–π interactions, with centroid–centroid distances of 3.7818 (19) and 3.9004 (17) Å. The cations, anions and water molecules are linked by O—H...O hydrogen bonds and weak C—H...O interactions, forming a three-dimensional network.