Crystal structures of three ortho-substituted N-acylhydrazone derivatives

Abstract

To explore the effect of the nature of substitutions on the structural parameters and hydrogen-bond interactions in N-acylhydrazone derivatives, the crystal structures of three ortho-substituted N-acylhydrazone derivatives, namely (E)-N-{2-[2-(2-chlorobenzylidene)hydrazinyl]-2-oxoethyl}-4-methylbenzenesulfonamide, C 16 H 16 ClN 3 O 3 S (I), (E)-N-{2-[2-(2-methylbenzylidene)hydrazinyl]-2-oxoethyl}-4-methylbenzenesulfonamide, C 17 H 19 N 3 O 3 S (II), and (E)-N-{2-[2-(2-nitrobenzylidene)hydrazinyl]-2-oxoethyl}-4-methylbenzenesulfonamide, C 16 H 16 N 4 O 5 S (III), have been determined. The structures of the three compounds display similar molecular conformations and hydrogen-bond patterns. The hydrazone part of the molecule, C-C-N-N=C, is almost planar in all the compounds, with the C-C-N-N and C-N-N=C torsion angles being 179.5(3) and 177.1(3), respectively, in (I),-179.4(2) and-177.1(3) in (II) and-179.7(2) and 173.4(2) in (III). The two phenyl rings on either side of the chain are approximately parallel to each other. In the crystal, the molecules are linked to each other via N-HO hydrogen bonds, forming ribbons with R 2 2 (8) and R 2 2 (10) ring motifs. The introduction of electron-withdrawing groups (by a chloro or nitro group) to produce compounds (I) or (III) results in C-HO hydrogen-bonding interactions involving the sulfonyl O atoms of adjacent ribbons, forming layers parallel to the ab plane in (I) or a three-dimensional network in (III). In (III), one O atom of the nitro group is disordered over two orientations with refined occupancy ratio of 0.836(12):0.164(12).