N-(3,5-Dichlorophenyl)-4-methylbenzenesulfonamide

In the crystal structure of the title compound, C13H11Cl2NO2S, the conformation of the N—C bond in the C—SO2—NH—C segment is gauche with respect to the SO bonds. The two benzene rings are tilted by 79.6 (1)° relative to each other. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds occur.

In the crystal structure of the title compound, C 13 H 11 Cl 2 NO 2 S, the conformation of the N-C bond in the C-SO 2 -NH-C segment is gauche with respect to the SO bonds. The two benzene rings are tilted by 79.6 (1) relative to each other. In the crystal, inversion dimers linked by pairs of N-HÁ Á ÁO hydrogen bonds occur.

Related literature
For the preparation of the title compound, see: Shetty & Gowda (2005). For background literature, see: For a study of the effect of substituents on the crystal structures of N-(aryl)arylsulfonamides, see: Gowda et al. (2008Gowda et al. ( , 2009a Table 1 Hydrogen-bond geometry (Å , ).

Comment
As part of a study of the substituent effects on the crystal structures of N-(aryl)-arylsulfonamides (Gowda et al., 2008;2009a, b), in the present work, the crystal structure of 4-methyl-N-(3,5-dichlorophenyl)benzenesulfonamide (I) has been determined. The conformation of the N-C bond in the C-SO 2 -NH-C segment of the structure has "trans" and "gauche" torsions with respect to the SO bonds (Fig. 1). The molecule is bent at the S atom with the C-SO 2 -NH-C torsion angle  (Table 1) into supramolecular structure is shown in Fig. 2.

Experimental
The solution of toluene (10 cc) in chloroform (40 cc) was treated dropwise with chlorosulfonic acid (25 cc) at 0 ° C. 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-methylbenzenesulfonylchloride was treated with 3,5-dichloroaniline in the stoichiometric ratio and boiled for 15 minutes. The reaction mixture was then cooled to room temperature and added to ice cold water (100 cc). The resultant 4-methyl-N-(3,5-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 prism like colourless 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 its position refined [N-H = 0.87 (5) Å]. The other H atoms were positioned with idealized geometry using a riding model [C-H = 0.93-0.96 Å]. All H atoms were refined with isotropic displacement parameters (set to 1.2 times of the U eq of the parent atom).
Two reflections (-5 1 9 and -3 2 11) were omitted from the refinement as a statistical analysis showed that they were anomalous.
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.  Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.