Crystal structures and Hirshfeld surface analyses of the two isotypic compounds (<i>E</i>)-1-(4-bromophenyl)-2-[2,2-dichloro-1-(4-nitrophenyl)ethenyl]diazene and (<i>E</i>)-1-(4-chlorophenyl)-2-[2,2-dichloro-1-(4-nitrophenyl)ethenyl]diazene

Abstract

In the two isotypic title compounds, C₁₄H₈BrCl₂N₃O₂, (<b>I</b>), and C₁₄H₈Cl₃N₃O₂, (<b>II</b>), the substitution of one of the phenyl rings is different [Br for (<b>I</b>) and Cl for (<b>II</b>)]. Aromatic rings form dihedral angles of 60.9 (2) and 64.1 (2)°, respectively. Mol-ecules are linked through weak <i>X</i>⋯Cl contacts [<i>X</i> = Br for (<b>I</b>) and Cl for (<b>II</b>)], C-H⋯Cl and C-Cl⋯π inter-actions into sheets parallel to the <i>ab</i> plane. Additional van der Waals inter-actions consolidate the three-dimensional packing. Hirshfeld surface analysis of the crystal structures indicates that the most important contributions for the crystal packing for (<b>I</b>) are from C⋯H/H⋯C (16.1%), O⋯H/H⋯O (13.1%), Cl⋯H/H⋯Cl (12.7%), H⋯H (11.4%), Br⋯H/H⋯Br (8.9%), N⋯H/H⋯N (6.9%) and Cl⋯C/C⋯Cl (6.6%) inter-actions, and for (<b>II</b>), from Cl⋯H / H⋯Cl (21.9%), C⋯H/H⋯C (15.3%), O⋯H/H⋯O (13.4%), H⋯H (11.5%), Cl⋯C/C⋯Cl (8.3%), N⋯H/H⋯N (7.0%) and Cl⋯Cl (5.9%) inter-actions. The crystal of (I) studied was refined as an inversion twin, the ratio of components being 0.9917 (12):0.0083 (12).