N-[(2-Chlorophenyl)sulfonyl]-3-nitrobenzamide

In the title compound, C13H9ClN2O5S, the dihedral angle between the benzene rings is 74.86 (11)°. The molecule is twisted at the S atom, with a dihedral angle of 82.53 (13)° between the sulfonyl benzene ring and the S—N—C=O segment. In the crystal, molecules are linked into inversion dimers through pairs of N—H⋯O hydrogen bonds, thereby forming R 2 2(8) loops. Molecules are linked into C(7) [010] chains by weak C—H⋯O hydrogen bonds, and C—H⋯π interactions are also observed.

In the title compound, C 13 H 9 ClN 2 O 5 S, the dihedral angle between the benzene rings is 74.86 (11) . The molecule is twisted at the S atom, with a dihedral angle of 82.53 (13) between the sulfonyl benzene ring and the S-N-C O segment. In the crystal, molecules are linked into inversion dimers through pairs of N-HÁ Á ÁO hydrogen bonds, thereby forming R 2 2 (8) loops. Molecules are linked into C(7) [010] chains by weak C-HÁ Á ÁO hydrogen bonds, and C-HÁ Á Á interactions are also observed.
PAS thanks the University Grants Commission (UGC), India, for financial support under its Minor Research Project scheme.

Experimental
The title compound was prepared by refluxing a mixture of 3-nitrobenzoic acid, 2-chlorobenzene sulfonamide and phosphorous oxy chloride for 2 h on a water bath. The resultant mixture was cooled and poured into ice cold water. The Solid obtained was filtered and 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 solid was recrystallized to the constant melting point (483 K).
Colorless prisms of (I) were obtained from a slow evaporation of its ethanolic solution at room temperature.

Refinement
The H atom of the NH group was located in a difference map and later restained to N-H = 0.81 (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).

Figure 4
Stacking of molecules along b axis through C-H···Cg interactions. Cg is the centroid of the nitrobenzene ring Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s 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 > 2σ(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. 119.4 (2) C8-C13-H13 120.1 C6-C1-S1