4-Chloro-N-(3,4-dimethylphenyl)benzenesulfonamide

In the title compound, C14H14ClNO2S, the angle between the sulfonyl and aniline benzene rings is 65.5 (1)°. The crystal structure features inversion dimers linked by pairs of N—H⋯O hydrogen bonds. The dimethylphenyl ring is disordered over two different orientations approximately related by a 180° rotation about the C—N bond, with occupancies of 0.643 (6) and 0.357 (6).

In the title compound, C 14 H 14 ClNO 2 S, the angle between the sulfonyl and aniline benzene rings is 65.5 (1) . The crystal structure features inversion dimers linked by pairs of N-HÁ Á ÁO hydrogen bonds. The dimethylphenyl ring is disordered over two different orientations approximately related by a 180 rotation about the C-N bond, with occupancies of 0.643 (6) and 0.357 (6).

Related literature
For the preparation of the title compound, see: Shetty & Gowda (2005). For our studies of the effect of substituents on the structures of N-(aryl)arylsulfonamides, see: Gowda et al. (2009Gowda et al. ( , 2010 Table 1 Hydrogen-bond geometry (Å , ).

Experimental
A solution of p-chlorobenzene (10 g) in chloroform (40 ml) was treated dropwise with chlorosulfonic acid (25 ml) at 273 K. 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 3,4-dimethylaniline in the stoichiometric ratio and boiled for 10 min. The reaction mixture was then cooled to room temperature and added to ice cold water (100 ml). The resultant solid 4-chloro-N-(3,4-dimethylphenyl)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). 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 refined with a distance restraint of N-H = 0.86 (1) Å.
The other H atoms were positioned with idealized geometry using a riding model with 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).
The dimethylphenyl ring is disordered such that atom C13 moves between atoms C9 and C11. Atoms C13 and C14 were refined using a split model. The corresponding site-occupation factors were refined so that their sum was unity [0.643 (6) and 0.357 (6)]. The corresponding bond distances in the disordered groups were restrained to be equal. The U ij parameters supplementary materials sup-2 of these atoms were restrained to an approximate isotropic behavoir. Attempts to introduce disorder of the atoms C9, C10 and C11 were unsuccessful. Fig. 1. The molecular structure of (I), showing the atom labelling scheme and displacement ellipsoids are drawn at the 50% probability level. Only the major disorder component is shown.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
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 Occ. (