Crystal structures and Hirshfeld surface analyses of (E)-1-[1-(4-tert-butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-phenyl­diazene, (E)-1-[1-(4-tert-butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-(4-methyl­phen­yl)diazene, (E)-1-[1-(4-tert-butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-(4-meth­oxy­phen­yl)diazene and (E)-1-[1-(4-tert-butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-(3-methyl­phen­yl)diazene

The crystal structures and Hirshfeld surface analyses of four similar azo compounds are reported. (E)-1-[1-(4-tert-Butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-phenyl­diazene, C18H18Cl2N2, (I), and (E)-1-[1-(4-tert-butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-(4-methyl­phen­yl)diazene, C19H20Cl2N2, (II), crystallize in the monoclinic space group C2/c with Z = 8, and (E)-1-[1-(4-tert-butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-(4-meth­oxy­phen­yl)diazene, C19H20Cl2N2O, (III), in the monoclinic space group P21/c with Z = 4. (E)-1-[1-(4-tert-Butyl­phen­yl)-2,2-di­chloro­ethen­yl]-2-(3-methyl­phen­yl)diazene, C19H20Cl2N2, (IV), crystallizes in the triclinic space group P with Z = 4 and comprises two mol­ecules (A and B) in the asymmetric unit. In the crystal structures of (I) and (II), mol­ecules are linked by C - H⋯π and C - Cl⋯π inter­actions, forming layers parallel to ( 02), while mol­ecules of (III) are linked by C - H⋯O contacts, C - H⋯π and C - Cl⋯π inter­actions forming layers parallel to ( 02). The stability of the mol­ecular packing is ensured by van der Waals forces between these layers. In the crystal structure of (IV), mol­ecules are linked by C - H⋯π and C - Cl⋯π inter­actions, forming a tri-periodic network. © 2023 International Union of Crystallography. All rights reserved.