Crystal structures of two dis-symmetric di-Schiff base compounds: 2-({(E)-2-[(E)-2,6-dichlorobenzylidene]hydrazin-1-ylidene}methyl)-6-methoxyphenol and 4-bromo-2-({(E)-2-[(E)-2,6-dichlorobenzylidene]hydrazin-1-ylidene}methyl)phenol

Abstract

Each of the title dis-symmetric di-Schiff base compounds, C15H12Cl2N2O2 (I) and C14H9BrCl2N2O (II), features a central azo-N—N bond connecting two imine groups, each with an E-configuration. One imine bond in each molecule connects to a 2,6-dichlorobenzene substituent while the other links a 2-hydroxyl-3-methoxy-substituted benzene ring in (I) or a 2-hydroxyl-4-bromo benzene ring in (II). Each molecule features an intramolecular hydroxyl-O—H...N(imine) hydrogen bond. The C—N—N—C torsion angles of −151.0 (3)° for (I) and 177.8 (6)° (II) indicates a significant twist in the former. The common feature of the molecular packing is the formation of supramolecular chains. In (I), the linear chains are aligned along the a-axis direction and the molecules are linked by methoxy-C—H...O(methoxy) and chlorobenzene-C—Cl...π(chlorobenzene) interactions. The chain in (II) is also aligned along the a axis but, has a zigzag topology and is sustained by Br...O [3.132 (4) Å] secondary bonding interactions. In each crystal, the chains pack without directional interactions between them. The non-covalent interactions are delineated in the study of the calculated Hirshfeld surfaces. Dispersion forces make the most significant contributions to the identified intermolecular interactions in each of (I) and (II).