N-(3-Chlorophenyl)-4-methylbenzenesulfonamide

In the title compound, C13H12ClNO2S, the conformation of the N—H bond is anti to the 3-chloro group in the aniline benzene ring. The dihedral angle between the two benzene rings is 73.7 (1)°. The crystal structure features inversion-related dimers linked by pairs of N—H⋯O hydrogen bonds.


Comment
In the present work, as part of a study of the effect of substituents on the crystal structures of N-(aryl)-arylsulfonamides (Gowda et al., 2008(Gowda et al., , 2009Nirmala et al., 2009), the structure of N-(3-chlorophenyl)4-methylbenzenesulfonamide (I) has been determined. The conformation of the N-C bond in the C1-SO 2 -NH-C7 segment of the structure has gauche torsions with respect to the S═O bonds ( Fig. 1). Further, the conformation of the N-H bond is anti to the 3-chloro group in the aniline benzene ring, similar to that observed in N-(3-chlorophenyl)-benzenesulfonamide (II) (Gowda et al., 2008) (Table 1) is shown in Fig.2.

Experimental
The solution of toluene (10 ml) in chloroform (40 ml) was treated dropwise with chlorosulfonic acid (25 ml) 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 benzenesulfonylchloride 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 solid N-(3chlorophenyl)4-methylbenzenesulfonamide 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 (Gowda et al., 2005). The rod like single crystals used in X-ray diffraction studies were grown in ethanolic solution by a 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 = 0.93-0.96 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).
supplementary materials sup-2 Figures   Fig. 1. Molecular structure of (I), showing the atom labelling scheme and displacement ellipsoids 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq C1 0.18744 (