Crystal structures and Hirshfeld surface analyses of methyl 4-{2,2-dichloro-1-[(E)-phenyldiazenyl]ethenyl}benzoate, methyl 4-{2,2-dichloro-1-[(E)-(4-methylphenyl)diazenyl]ethenyl}benzoate and methyl 4-{2,2-dichloro-1-[(E)-(3,4-dimethylphenyl)diazenyl]ethenyl}benzoate

Abstract

The crystal structures and Hirshfeld surface analyses of three similar azo compounds are reported. Methyl 4-{2,2-dichloro-1-[(E)-phenyldiazenyl]ethenyl}benzoate, C16H12Cl2N2O2, (I), and methyl 4-{2,2-dichloro-1-[(E)-(4-methylphenyl)diazenyl]ethenyl}benzoate, C17H14Cl2N2O2, (II), crystallize in the space group P21/c with Z = 4, and methyl 4-{2,2-dichloro-1-[(E)-(3,4-dimethylphenyl)diazenyl]ethenyl}benzoate, C18H16Cl2N2O2, (III), in the space group P\overline{1} with Z = 2. In the crystal of (I), molecules are linked by C—H...N hydrogen bonds, forming chains with C(6) motifs parallel to the b axis. Short intermolecular Cl...O contacts of 2.8421 (16) Å and weak van der Waals interactions between these chains stabilize the crystal structure. In (II), molecules are linked by C—H...O hydrogen bonds and C—Cl...π interactions, forming layers parallel to (010). Weak van der Waals interactions between these layers consolidate the molecular packing. In (III), molecules are linked by C—H...π and C—Cl...π interactions forming chains parallel to [011]. Furthermore, these chains are connected by C—Cl...π interactions parallel to the a axis, forming (0\overline{1}1) layers. The stability of the molecular packing is ensured by van der Waals forces between these layers.