Synthesis, crystal structure, and Hirshfeld surface analysis of 1,3-dihydro-2H-benzimidazol-2-iminium 3-carboxy-4-hydroxybenzenesulfonate

The asymmetric unit of the title salt, C 7 H 8 N 3 + ·C 7 H 5 O 6 S − , comprises two 1,3-dihydro-2 H -benzimidazol-2-iminium cations and two 2-hydroxy-5-sulfobenzoate anions ( Z ′ = 2). In the crystal, the molecules interact through N—H...O, O—H...O hydrogen bonds and C—O...π contacts. The hydrogen-bonding interactions lead to the formation of layers parallel to (1̄01). Hirshfeld surface analysis revealed that H...H contacts contribute to most of the crystal packing with 38.9%, followed by H...O contacts with 36.2%.