1-[(E)-2-(2-Hydroxy-5-methylphenyl)diazen-2-ium-1-yl]naphthalen-2-olate

Abstract

The title zwitterion, C17H14N2O2, crystallizes with two independent molecules in the asymmetric unit, both of which are approximately planar, the dihedral angles between the benzene ring and the naphthalene ring system being 4.39 (12)° in one molecule and 5.83 (12)° in the other, and show an E conformation with respect to the azo double bond. An intramolecular N—H...O hydrogen bond in each molecule helps to establish their near planar conformation. In the crystal, molecules are linked through O—H...O hydrogen bonds into infinite chains running along the a-axis direction. In addition, the chains are stacked along the b axis via π–π interactions between the benzene and the naphthalene rings of adjacent molecules, the centroid–centroid distances being 3.722 (3) and 3.823 (4) Å.