4-Chloro-N-(2-chlorobenzoyl)benzenesulfonamide

In the structure of the title compound, C13H9Cl2NO3S, the conformation of the N—H bond in the C—SO2—NH—C(O) segment is anti to the C=O bond. The molecule is twisted at the S atom with a torsion angle of 65.7 (2)°. The dihedral angle between the sulfonyl benzene ring and the —SO2—NH—C—O segment is 88.5 (1)°, and that between the sulfonyl and the benzoyl benzene rings is 58.0 (1)°. In the crystal, molecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers.

In the structure of the title compound, C 13 H 9 Cl 2 NO 3 S, the conformation of the N-H bond in the C-SO 2 -NH-C(O) segment is anti to the C O bond. The molecule is twisted at the S atom with a torsion angle of 65.7 (2) . The dihedral angle between the sulfonyl benzene ring and the -SO 2 -NH-C-O segment is 88.5 (1) , and that between the sulfonyl and the benzoyl benzene rings is 58.0 (1) . In the crystal, molecules are linked by pairs of N-HÁ Á ÁO hydrogen bonds, forming inversion dimers.

Related literature
For our study of the effect of ring and side-chain substituents on the crystal structures of N-aromatic sulfonamides and for related structures, see: Gowda et al. (2010); Suchetan et al. (2010a,b,c Table 1 Hydrogen-bond geometry (Å , ).

Experimental
The title compound was prepared by refluxing a mixture of 2-chlorobenzoic acid, 4-chlorobenzenesulfonamide and phosphorous oxy chloride for 3 h on a water bath. The resultant mixture was cooled and poured into ice cold water. The solid 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. It was filtered, dried and recrystallized.
Prism like colourless single crystals of the title compound used in X-ray diffraction studies were obtained by 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 N-H = 0.86 (2) %A. 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). Fig. 1. Molecular structure of the title compound, showing the atom-labelling scheme. 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. 119.0 (2) C12-C13-C8 120.0 (2) C4-C5-H5 120.5 C12-C13-H13 120.0 C6-C5-H5 120.5 C8-C13-H13 120.0 C5-C6-C1