2-[(E)-(3-Carboxy-4-hydroxyphenyl)iminiomethyl]-4-chlorophenolate

The title Schiff base compound, C14H10ClNO4, has been synthesized by the reaction of 5-amino-2-hydroxybenzoic acid and 5-chloro-2-hydroxybenzaldehyde. The molecule is a zwitterion in the crystal, with the phenolic hydroxy group deprotonated and the imine N atom protonated. It adopts an E configuration about the central C=N double bond. The dihedral angle between the two benzene rings is 3.83 (7)°. Intramolecular N—H...O and O—H...O hydrogen bonding generates S(6) ring motifs. In the crystal, molecules are connected by intermolecular O—H...O and C—H...Cl hydrogen bonds, forming a supramolecular chain