Zwitterionic 1-{(1E)-[(4-hy-droxy-phen-yl)iminio]meth-yl}naphthalen-2-olate: crystal structure and Hirshfeld surface analysis.

The title zwitterion, C17H13NO2 (systematic name: 1-{(1E)-[(4-hy-droxy-phen-yl)iminium-yl]meth-yl}naphthalen-2-olate), features an intra-molecular charge-assisted N+-H⋯O- hydrogen bond. A twist in the mol-ecule is evident around the N-C(hy-droxy-benzene) bond [C-N-C-C torsion angle = 39.42 (8)°] and is reflected in the dihedral angle of 39.42 (8)° formed between the aromatic regions of the mol-ecule. In the crystal, zigzag supra-molecular chains along the a axis are formed by charge-assisted hy-droxy-O-H⋯O(phenoxide) hydrogen bonding. These are connected into a layer in the ab plane by charge-assisted hy-droxy-benzene-C-H⋯O(phenoxide) inter-actions and π-π contacts [inter-centroid distance between naphthyl-C6 rings = 3.4905 (12) Å]. Layers stack along the c axis with no specific inter-actions between them. The Hirshfeld surface analysis points to the significance C⋯H contacts between layers.