4-Chloro-N-(3-chlorophenyl)benzenesulfonamide

In the crystal of the title compound, C12H9Cl2NO2S, the molecule is twisted at the S atom with a C—SO2—NH—C torsion angle of −58.4 (3)°. Furthermore, the N—H bond in this segment is anti to the meta-chloro group. The dihedral angle between the aromatic rings is 77.1 (1)°. The crystal structure features inversion-related dimers linked by N—H⋯O hydrogen bonds.

In the crystal of the title compound, C 12 H 9 Cl 2 NO 2 S, the molecule is twisted at the S atom with a C-SO 2 -NH-C torsion angle of À58.4 (3) . Furthermore, the N-H bond in this segment is anti to the meta-chloro group. The dihedral angle between the aromatic rings is 77.1 (1) . The crystal structure features inversion-related dimers linked by N-HÁ Á ÁO hydrogen bonds.

Related literature
For our study on the effect of substituents on the structures of N-(aryl)arylsulfonamides, see: Gowda et al. (2005); Shakuntala et al. (2011). For the effect of substituents on the oxidative strengths of N-chloro,N-arylsulfonamides, see: Gowda & Shetty (2004) and for the effect of substituents on the NQR spectra of N-(aryl)-amides, see: Gowda et al. (2000).
KS thanks the University Grants Commission, Government of India, New Delhi, for the award of a research fellowship under its faculty improvement program.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: DS2101).
The N-H bond and the meta-chloro group in the anilino benzene ring are anti to each other.
The sulfonyl and the anilino benzene rings in (I) are tilted relative to each other by 77.1 (1)°, compared to the value of 56.5 (1)° in (II).

Inermolecular N-H···O(S) hydrogen bonding interactions generates inversion related dimers which are further packed
via van der Waals interactions in the crystal structure (Fig.2).
After the initial evolution of hydrogen chloride subsided, the reaction mixture was brought to room temperature and poured into crushed ice in a beaker. The chloroform layer was separated, washed with cold water and allowed to evaporate slowly.
The residual 4-chlorobenzenesulfonylchloride was treated with 3-chloroaniline in the stoichiometric ratio and boiled for ten minutes. The reaction mixture was then cooled to room temperature and added to ice cold water (100 ml). The resultant 4-chloro-N-(3-chlorophenyl)-benzenesulfonamide was filtered under suction and washed thoroughly with cold water. It was then recrystallized to constant melting point from dilute ethanol. The compound was characterized by FT-IR and NMR spectra.
Prism like colorless single crystals used in X-ray diffraction studies were grown in ethanolic solution by slow evaporation at room temperature.

Refinement
The H atom of the NH group was 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 Å A l l H atoms were refined with isotropic displacement parameters (set to 1.2 times of the U eq of the parent atom). The weak diffraction of the crystal resulted in low theta value. However, the refinement went well supplementary materials sup-2 Figures   Fig. 1. Molecular structure of (I), showing the atom labelling scheme and displacement ellipsoids are drawn at the 50% probability level.   (7) 0.0044 (7) 0.0125 (6) 0.0095 (7) S1 0.0592 (5) 0.0493 (5) 0.0572 (6) 0.0048 (4) 0.0031 (4) 0.0025 (4) Geometric parameters (Å, °)