N-(2-Chlorophenyl)-4-nitrobenzenesulfonamide

In the title compound, C12H9ClN2O4S, the dihedral angle between the benzene rings is 70.60 (11)°. An intramolecular N—H⋯Cl contact occurs. In the crystal, molecules form inversion dimers via pairs of N—H⋯O hydrogen bonds.

The conformation of the N-C bond in the -SO 2 -NH-C segment has gauche torsion with respect to the S═O bonds The dihedral angle between the sulfonyl and the anilino rings is 70.60 (11)°, compared to the value of 51.11 (10)° in (II).
The amide H-atom showed bifurcated intramolecular H-bonding with the ortho-Cl atom in the anilino benzene ring and the intermolecular H-bonding with the sulfonyl oxygen atom of the other molecule, generating C(6) and R 2 2 (8) motifs (Adsmond et al., 2001;Allen et al., 1998;Bernstein et al., 1995;Etter, 1990).
In the crystal structure, the molecules form centrosymmetric dimers vi N-H···O hydrogen bonds. Part of the crystal structure is shown in Fig. 2.

Experimental
The title compound was prepared by treating 4-nitrobenzenesulfonylchloride with 2-chloroaniline in the stoichiometric ratio and boiling the reaction mixture for 15 minutes. The reaction mixture was then cooled to room temperature and added to ice cold water (100 ml). The resultant solid N-(2-chlorophenyl)-4-nitrobenzenesulfonamide was filtered under suction and washed thoroughly with cold water and dilute HCl to remove the excess sulfonylchloride and aniline, respectively. It was then recrystallized to constant melting point from dilute ethanol. The purity of the compound was checked and characterized by its infrared spectra.
Prism like light pink single crystals of the title compound used in X-ray diffraction studies were grown in ethanolic solution by slow evaporation of the solvent at room temperature.

Refinement
H atoms bonded to C were positioned with idealized geometry using a riding model with the aromatic C-H = 0.93 Å.
The amino H atom was freely refined with the N-H distance restrained to 0.86 (2) Å. All H atoms were refined with isotropic displacement parameters set at 1.2 U eq of the parent atom.   Bifurcated hydrogen bonding in the title compound. 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 R-factors(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. 1.390 (4) O1-S1 1.429 (2) C7-N1 1.425 (4) O2-S1 1.423 (2) C2-C1-C6 121.2 (3) C10-C9-C8 119.9 (3) C2-C1-S1