Crystal structure and Hirshfeld surface analysis of ()-'-benzyl-idene-4-chloro-benzene-sulfono-hydrazide and of its ()-4-chloro-'-(- and -methyl-benzyl-idene)benzene-sulfono-hydrazide derivatives.

()-'-Benzyl-idene-4-chloro-benzene-sulfono-hydrazide, CHClNOS, (I), and its - and -methyl-substituted derivatives, CHClNOS, namely ()-4-chloro-'-(2-methyl-benzyl-idene)benzene-sulfono-hydrazide, (II), and ()-4-chloro-'-(4-methyl-benzyl-idene)benzene-sulfono-hydrazide, (III), have been synthesized, characterized spectroscopically and their crystal structures determined to investigate the effect of the substitution site of the benzyl-idene group on the structural and supra-molecular features in these compounds. Compounds (I) and (II) are isotypic while compound (III) is different. All three mol-ecules are bent at the S atom with C-S-N-N torsion angles of -66.0 (3), -66.0 (3) and -58.4 (2)° for (I), (II) and (III), respectively. The hydrazone portions of the mol-ecules, S-N-N=C, are slightly twisted from planarity, with a torsion angle of 166.5 (3)° in (I), 165.4 (3)° in (II) and 157.9 (2)° in (III). The two aromatic rings present in the compounds are inclined to each other by 78.4 (2), 74.8 (2) and 76.9 (1)° in (I), (II) and (III), respectively. In the crystal structure of the parent compound (I), and of the -methyl derivative (II), an N-H⋯O hydrogen bond links the mol-ecules into chains along [001], which are inter-connected by weak inter-molecular C-H⋯O inter-actions, generating layers lying parallel to the plane. In the crystal of the derivative (III), however, the packing is significantly different. Here mol-ecules are linked by pairs of N-H⋯O hydrogen bonds, forming inversion dimers with an (8) ring motif. The dimers are then linked by C-Cl⋯π inter-actions, forming ribbons propagating along [10]. Hirshfeld surface analyses show that the van der Waals inter-actions constitute the major contribution to the inter-molecular inter-actions in the crystal structures of all three compounds. The fingerprint plots indicate that the H⋯H contacts make the largest contributions to the Hirshfeld surfaces.