2-{(1)-[()-2-(2,6-Di-chloro-benzyl-idene)hydrazin-1-yl-idene]meth-yl}phenol: crystal structure, Hirshfeld surface analysis and computational study.

The title Schiff base compound, CHClNO, features an configuration about each of the C=N imine bonds. Overall, the mol-ecule is approximately planar with the dihedral angle between the central CN residue (r.m.s. deviation = 0.0371 Å) and the peripheral hy-droxy-benzene and chloro-benzene rings being 4.9 (3) and 7.5 (3)°, respectively. Nevertheless, a small twist is evident about the central N-N bond [the C-N-N-C torsion angle = -172.7 (2)°]. An intra-molecular hy-droxy-O-H⋯N(imine) hydrogen bond closes an (6) loop. In the crystal, π-π stacking inter-actions between hy-droxy- and chloro-benzene rings [inter-centroid separation = 3.6939 (13) Å] lead to a helical supra-molecular chain propagating along the -axis direction; the chains pack without directional inter-actions between them. The calculated Hirshfeld surfaces point to the importance of H⋯H and Cl⋯H/H⋯Cl contacts to the overall surface, each contributing approximately 29% of all contacts. However, of these only Cl⋯H contacts occur at separations less than the sum of the van der Waals radii. The aforementioned π-π stacking inter-actions contribute 12.0% to the overall surface contacts. The calculation of the inter-action energies in the crystal indicates significant contributions from the dispersion term.