Crystal structures of 4-chloro­phenyl N-(3,5-di­nitro­phen­yl)carbamate and phenyl N-(3,5-di­nitro­phen­yl)carbamate

The title compounds, C(13)H(8)ClN(3)O(6), (I), and C(13)H(9)N(3)O(6), (II), differ in the orientation of the two aromatic rings. In (I), they are essentially coplanar, making a dihedral angle of 8.2 (1)°, while in (II), they are inclined to one another by 76.2 (1)°. The two nitro groups are essentially coplanar with the attached benzene rings, as indicated by the dihedral angles of 1.4 (2) and 2.3 (2)° in (I), and 4.96 (18) and 5.4 (2)° in (II). The carbamate group is twisted slightly from the attached benzene ring, with a C—N—C—O torsion angle of −170.17 (15)° for (I) and 168.91 (13)° for (II). In the crystals of of both compounds, mol­ecules are linked via N—H⋯O hydrogen bonds, forming chains propagating along [010]. In (I), C—H⋯O hydrogen bonds also link mol­ecules within the chains. The crystal packing in (I) also features a very weak π–π inter­action [centroid–centroid distance = 3.7519 (9) Å].