S-5-Amino-2-(dimethylammonio)phenyl sulfothioate

Abstract

The title compound, C8H12N2O3S2, has been isolated as a by-product in the synthesis of methylene blue dye. The compound crystallizes with four independent molecules in the unit cell (Z′= 4). The zwitterionic form of the molecule was established on the basis of the hydrogen atom located at the dimethylamino group. The crystal structure is dominated by intermolecular hydrogen bonds of the N—H...O type formed between amino and ammonio N—H groups and O atoms from the sulfothioate group. There are in addition two weak intermolecular N—H...N interactions and some non-conventional C—H...O hydrogen bonds.