2-Amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium 3-carboxy-4-hydroxybenzenesulfonate monohydrate

Abstract

The asymmetric unit of the title molecular salt, C4H7N3O+·C7H5O6S−·H2O, contains a 5-sulfosalicylate anion, a creatininium cation and a water molecule of crystallization. The cation is protonated at the imidazole N atom and the anion is deprotonated at the sulfonic acid group. The creatininium is disordered over two sets of sites with refined site occupancies of 0.771 (3) and 0.229 (3). The benzene ring is approximately orthogonal to the disordered five-membered rings [dihedral angles of 89.7 (2) and 88.3 (8)° for the major and minor occupancy components, respectively]. In the crystal, the ions are connected through pairs of N—H...O hydrogen bonds, generating an R22(8) ring-motif. An intraionic O—H...O hydrogen bond generates an S(6) graph-set motif. Weak C—H...O contacts link the ions and water molecule into a two-dimensional network parallel to (001). The structure was refined as a two-component twin.

Keywords

• molecular salt
• crystal structure
• hydrogen bonding