N-(2,4-Dichlorophenyl)benzenesulfonamide

The title compound, C12H9Cl2NO2S, crystallizes with two independent molecules in the asymmetric unit. The dihedral angles between the two aromatic rings are 70.8 (1) and 74.8 (1)° for the two molecules. The crystal structure features dimers made up of one each of the two asymmetric molecules linked by pairs of N—H⋯O hydrogen bonds. An intramolecular N—H⋯Cl hydrogen bond is also observed in both molecules.

The title compound, C 12 H 9 Cl 2 NO 2 S, crystallizes with two independent molecules in the asymmetric unit. The dihedral angles between the two aromatic rings are 70.8 (1) and 74.8 (1) for the two molecules. The crystal structure features dimers made up of one each of the two asymmetric molecules linked by pairs of N-HÁ Á ÁO hydrogen bonds. An intramolecular N-HÁ Á ÁCl hydrogen bond is also observed in both molecules.

Experimental
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BT5148).

N-(2,4-Dichlorophenyl)benzenesulfonamide
B. T. Gowda, S. Foro, P. G. Nirmala and H. Fuess Comment In the present work, as part of a study of substituent effects on the structures of N-(aryl)arylsulfonamides (Gowda et al., 2008;Gowda et al., 2010), the structure of N-(2,4-Dichlorophenyl)benzenesulfonamide (I) has been determined. The asymmetric unit of the structure contains two independent molecules.
The sulfonyl benzene and the aniline benzene rings in the two molecules of (I) are tilted relative to each other by 70.8 (1)°( molecule 1) and 74.8 (1)° (molecule 2). The other bond parameters in (I) are similar to those observed in other aryl sulfonamides (Gowda et al., 2010;Perlovich et al., 2006;Gelbrich et al., 2007).
In the crystal structure, both the intramolecular N-H···Cl and intermolecular N-H···O hydrogen bonds are observed.
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 benzenesulfonylchloride was treated with 2,4-dichloroaniline in the stoichiometric amounts and boiled for ten minutes. The reaction mixture was then cooled to room temperature and added to ice cold water (100 ml). The resultant solid N-(2,4-dichlorophenyl)benzenesulfonamide was filtered under suction and washed thoroughly with cold water. It was then recrystallized to constant melting point from dilute ethanol. The purity of the compound was checked and characterized by recording its infrared and NMR spectra (Shetty & Gowda, 2005). The rod like colorless single crystals used in X-ray diffraction studies were grown in ethanolic solution by evaporating it at room temperature.

Refinement
The H atoms of the NH groups were located in a difference map and refined with a N-H distance restraint of 0.86 (1) 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).   (3) 113 (3)