1,8-Bis(3-chloroanilino)-N,N′-bis(3-chlorophenyl)octane-1,8-diimine

There are two half-molecules in the asymmetric unit of the title compound, C32H30Cl4N4, in both of which the N—H bonds are syn to the meta-chloro substituents in the adjacent benzene ring. The other two Cl atoms of these two molecules are disordered with occunpancy ratios of 0.79 (2):0.21 (2) and 0.68 (1):0.32 (1). Adjacent chlorophenyl rings make dihedral angles of 74.3 (2) and 63.0 (2)° in the two molecules. In the crystal, intermolecular N—H⋯N hydrogen bonds link the molecules into infinite chains.

There are two half-molecules in the asymmetric unit of the title compound, C 32 H 30 Cl 4 N 4 , in both of which the N-H bonds are syn to the meta-chloro substituents in the adjacent benzene ring. The other two Cl atoms of these two molecules are disordered with occunpancy ratios of 0.79 (2):0.21 (2) and 0.68 (1):0.32 (1). Adjacent chlorophenyl rings make dihedral angles of 74.3 (2) and 63.0 (2) in the two molecules. In the crystal, intermolecular N-HÁ Á ÁN hydrogen bonds link the molecules into infinite chains.

Related literature
For our study on the effect of substituents on the structures of this class of compounds, see: Gowda et al. (2007Gowda et al. ( , 2009Gowda et al. ( , 2010
Atoms Cl2 and Cl4 in (I) are disordered and were refined using a split model. The site-occupation factors were refined so that their sum was unity [0.79 (2) and 0.22 (2) for Cl2, 0.68 (1) and 0.32 (1) for Cl4, respectively]. The corresponding bond distances in the disordered groups were restrained to be equal.

Experimental
Suberic acid (0.2 mol) was heated with Phosphorus oxychloride (1.2 mol) at 70°C for 2 h. The acid chloride obtained was treated with 3-chloroaniline (0.8 mol). The product obtained was added to crushed ice to obtain the precipitate. It was thoroughly washed with water and then with saturated sodium bicarbonate solution and washed again with water. It was then given a wash with 2 N HCl. It was again washed with water, filtered, dried and recrystallized from ethanol.
Prism like colorless single crystals of the title compound used in x-ray diffraction studies were obtained by a slow evaporation of its solution at room temperature.

supplementary materials sup-2 Refinement
The H atoms of the NH groups were located in a difference map and later restrained to the distance N-H = 0.86 (2) Å. The other H atoms were positioned with idealized geometry using a riding model with C-H = 0.93-0.97 Å. All H atoms were refined with isotropic displacement parameters (set to 1.2 times of the U eq of the parent atom).
Atoms Cl2 and Cl4 are disordered and were refined using a split model. The corresponding site-occupation factors were refined so that their sum was unity [0.79 (2) and 0.21 (2) for Cl2, 0.68 (1) and 0.32 (1) for Cl4, respectively] and their corresponding bond distances in the disordered groups were restrained to be equal. The U ij components of Cl2, Cl4, C16 and C27 were restrained to approximate isotropic behavior. Fig. 1. Molecular structure of (I), showing the atom labeling and displacement ellipsoids drawn at the 50% probability level. Both disorder components are shown. The minor disorder components are shown with dashed bonds. Symmetry codes for the unlabeled atoms: -x+1, y, -z+1/2 and -x+3/2, -y+1/2, -z+1.