Crystal structure and Hirshfeld surface analysis of 1-[(E)-2-(3-nitrophenyl)diazen-1-yl]naphthalen-2-ol

The title compound, C16H11N3O3, belongs to the family of azo dyes. In the light of a single-crystal X-ray study, it is evident that of the tautomeric forms (azohydrazone), the hydrazone form is the predominant form in the solid state, namely, (1E)-1-[2-(3-nitrophenyl)hydrazin-1-ylidene]-1,2-dihydronaphthalen-2one. The naphthol and benzene fragments attached to the -N = N- moiety adopt the s-trans conformation. Furthermore, the molecules are nearly coplanar, subtending a dihedral angle of 2.63 (5)degrees. An intramolecular N-H center dot center dot center dot O hydrogen bond occurs. There are only two types of intermolecular interactions in the crystal structure: strong hydrogen-bonding C-H center dot center dot center dot O interactions and pi-pi stacking interactions. The importance of C-H center dot center dot center dot O interactions in the molecular packing is reflected by the relatively high contributions (28.5%) made by O center dot center dot center dot H/H center dot center dot center dot O contacts to the Hirshfeld surface.