4-Chloro-N-(3-chlorobenzoyl)benzenesulfonamide monohydrate

In the title compound, C13H9Cl2NO3S·H2O, the conformation of the C=O bond is syn to the meta-Cl group in the benzoyl ring. The molecules are twisted at the S—N bond with a C—S—N—C torsion angle of 72.9 (2)°. The dihedral angle between the sulfonyl benzene ring and the S—NH—C—O segment is 77.8 (1)° and that between the sulfonyl and benzoyl benzene rings is 80.5 (1)°. In the crystal, molecules are linked into a two-dimensional network parallel to (100) by N—H⋯O and O—H⋯O hydrogen bonds.

In the title compound, C 13 H 9 Cl 2 NO 3 SÁH 2 O, the conformation of the C O bond is syn to the meta-Cl group in the benzoyl ring. The molecules are twisted at the S-N bond with a C-S-N-C torsion angle of 72.9 (2) . The dihedral angle between the sulfonyl benzene ring and the S-NH-C-O segment is 77.8 (1) and that between the sulfonyl and benzoyl benzene rings is 80.5 (1) . In the crystal, molecules are linked into a two-dimensional network parallel to (100) by N-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds.

Comment
As a part of studying the effect of ring and the side chain substituents on the crystal structures of N-aromatic sulfonamides (Gowda et al., 2009(Gowda et al., , 2010Suchetan et al., 2010a,b), the structure of 4-chloro-N-(3-Chlorobenzoyl)benzenesulfonamide monohydrate (I) has been determined (Fig.1).
Further, the conformation of the C═O bond in the C-SO 2 -NH-C(O) segment of (I) is syn to the meta-Cl in the benzoyl ring, similar to that observed between the C═O bond and ortho-Cl in (IV), but contrary to the anti conformation observed between the C═O bond and meta-Cl in (II).

Experimental
The title compound was prepared by refluxing a mixture of 3-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. Long needle 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 atom of the NH group and the H atoms of the water molecule were located in a difference map and later restrained to N-H = 0.86 (2) %A and to O-H = 0.85 (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.

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