N-Benzoyl-4-chlorobenzenesulfonamide

The asymmetric unit of the title compound, C13H10ClNO3S, contains two independent molecules. The molecules have C—S—N—C torsion angles of −70.0 (2) and 61.3 (2)° for molecules 1 and 2, respectively. The dihedral angles between the sulfonyl benzene rings and the –SO2—NH—C—O segments are 72.0 (1) and 77.3 (1)° for molecules 1 and 2, respectively, and the dihedral angles between the sulfonyl and the benzoyl benzene rings are 62.8 (1) and 78.6 (1)°, respectively. In the crystal, molecules 1 and 2 are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers.

The asymmetric unit of the title compound, C 13 H 10 ClNO 3 S, contains two independent molecules. The molecules have C-S-N-C torsion angles of À70.0 (2) and 61.3 (2) for molecules 1 and 2, respectively. The dihedral angles between the sulfonyl benzene rings and the -SO 2 -NH-C-O segments are 72.0 (1) and 77.3 (1) for molecules 1 and 2, respectively, and the dihedral angles between the sulfonyl and the benzoyl benzene rings are 62.8 (1) and 78.6 (1) , respectively. In the crystal, molecules 1 and 2 are linked by pairs of N-HÁ Á ÁO hydrogen bonds, forming inversion dimers.

Related literature
For background to our study of the effect of ring and sidechain substituents on the crystal structures of N-aromatic sulfonamides and for similar structures, see: Gowda et al. (2009;2010); Suchetan et al. (2009 Table 1 Hydrogen-bond geometry (Å , ).   (Table 1) is shown in Fig. 2.

Experimental
The title compound was prepared by refluxing a mixture of benzoic acid, 4-chlorobenzenesulfonamide and phosphorous oxy chloride for 5 h on a water bath. The resultant mixture was cooled and poured into ice cold water. The solid, N-(benzoyl)4chlorobenzenesulfonamide obtained was filtered, washed thoroughly with water and then dissolved in sodium bicarbonate solution. The compound was later reprecipitated by acidifying the filtered solution with dilute HCl. The filtered and dried compound was recrystallized to the constant melting point.
Prism like colourless single crystals of the title compound used in X-ray diffraction studies were grown from a slow evaporation of its toluene solution at room temperature.

Refinement
The H atoms of the NH groups were 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. All H atoms were refined with isotropic displacement parameters (set to 1.2 times of the U eq of the parent atom).

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.