N,N′-Bis(3-chlorophenyl)malonamide

The asymmetric unit of the title compound, C15H12Cl2N2O2, contains two independent molecules. In both independent molecules, the N—H bond in one of the amide fragments is anti to the meta-chloro group of the adjacent benzene ring and that in the other amide group is syn to the other meta-chloro group. Furthermore, in both molecules, each amide group is almost coplanar with the adjacent phenyl ring, making dihedral angles of 10.5 (2) and 8.7 (2)° in one molecule and 9.0 (2) and 9.6 (2)° in the other. The planes of the amide groups are inclined at dihedral angles of 83.4 (1) and 87.4 (1)° in the two molecules. In the crystal, molecules are linked into a chain by intermolecular N—H⋯O hydrogen bonds.

The asymmetric unit of the title compound, C 15 H 12 Cl 2 N 2 O 2 , contains two independent molecules. In both independent molecules, the N-H bond in one of the amide fragments is anti to the meta-chloro group of the adjacent benzene ring and that in the other amide group is syn to the other meta-chloro group. Furthermore, in both molecules, each amide group is almost coplanar with the adjacent phenyl ring, making dihedral angles of 10.5 (2) and 8.7 (2) in one molecule and 9.0 (2) and 9.6 (2) in the other. The planes of the amide groups are inclined at dihedral angles of 83.4 (1) and 87.4 (1) in the two molecules. In the crystal, molecules are linked into a chain by intermolecular N-HÁ Á ÁO hydrogen bonds.   Table 1 Hydrogen-bond geometry (Å , ).
VZR thanks the University Grants Commission, Government of India, New Delhi, for award of an RFSMS research fellowship.
In the crystal, the molecules are linked into chains by intermolecular N-H···O hydrogen bonding as shown in Fig. 2 ( Table 1) .

Experimental
Malonic acid (0.3 mol) in dichloromethane (30 ml) was treated with m-chloroaniline (0.6 mol) in dichloromethane (30 ml), dropwise with stirring. The resulting mixture was stirred for 3 hrs and kept aside for 12 hrs for the completion of reaction and evaporation of the solvent, dichloromethane. The product obtained was added to crushed ice to obtain the precipitate.
The latter 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 to the constant melting point 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 ehanolic solution at room temperature.

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 the aromatic C-H = 0.93Å and supplementary materials sup-2 the methylene C-H = 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). Fig. 1. Molecular structure of the title compound, showing the atom labelling scheme with displacement ellipsoids drawn at the 50% probability level.