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

Abstract

In the two isotypic title compounds, C14H8BrCl2N3O2, (I), and C14H8Cl3N3O2, (II), the substitution of one of the phenyl rings is different [Br for (I) and Cl for (II)]. Aromatic rings form dihedral angles of 60.9 (2) and 64.1 (2)°, respectively. Molecules are linked through weak X...Cl contacts [X = Br for (I) and Cl for (II)], C—H...Cl and C—Cl...π interactions into sheets parallel to the ab plane. Additional van der Waals interactions consolidate the three-dimensional packing. Hirshfeld surface analysis of the crystal structures indicates that the most important contributions for the crystal packing for (I) 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%) interactions, and for (II), 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%) interactions. The crystal of (I) studied was refined as an inversion twin, the ratio of components being 0.9917 (12):0.0083 (12).

Keywords

• crystal structure
• diazene derivatives
• dyes
• intermolecular halogen bonds
• Hirshfeld surface analysis