N-(4-Chlorophenyl)-4-nitrobenzenesulfonamide

In the title compound, C12H9ClN2O4S, the dihedral angle between the benzene rings is 31.4 (2)°. In the crystal, N—H⋯O hydrogen bonds link the molecules into C(4) chains running along the a-axis direction.

In the title compound, C 12 H 9 ClN 2 O 4 S, the dihedral angle between the benzene rings is 31.4 (2) . In the crystal, N-HÁ Á ÁO hydrogen bonds link the molecules into C(4) chains running along the a-axis direction.
The conformation of the N-C bond in the -SO 2 -NH-C segment has gauche torsions with respect to the S═O bonds ( Fig. 1 In the crystal, intermolecular N-H···O hydrogen bond interactions link the molecules into C(4) chains. Part of the crystal structure is shown in Fig. 2.

Experimental
The title compound was prepared by treating 4-nitrobenzenesulfonylchloride with 4-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-(4-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 from dilute ethanol. The purity of the compound was checked and characterized by its infrared spectra.
Prism like colourless single crystals of the title compound used in X-ray diffraction studies were grown in an 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.  Molecular structure of the title compound, showing the atom labelling scheme and with displacement ellipsoids drawn at the 50% probability level.

Figure 2
Molecular packing of the title compound with hydrogen bonding shown as dashed lines. 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.