Crystal structure of 3-(2-hydroxyethyl)-2-methylsulfanyl-6-nitro-3H-benzimidazol-1-ium chloride monohydrate

In the cation of the title hydrated molecular salt, C10H12N3O3S+center dot Cl-center dot H2O, the benzimidazolium ring system is almost planar (r. m. s. deviation = 0.006 angstrom) and the nitro group is inclined at an angle of 4.86 (9)degrees to this plane. In the crystal, C-H center dot center dot center dot O hydrogen bonds form centrosymmetric R-2(2) (20) dimers and these are further aggregated through N-H center dot center dot center dot O and O-H center dot center dot center dot Cl hydrogen bonds involving the water molecules and chloride anions. Aromatic pi-pi stacking interactions are also found between two parallel benzene rings or the benzene and imidazolium rings, with centroid-centroid distances of 3.5246 (9) and 3.7756 (9) angstrom, respectively. Analysis of the bond lengths and comparison with related compounds show that the nitro substituent is not involved in conjugation with the adjacent pi-system and hence has no effect on the charge distribution of the heterocyclic ring.