N-(3-Chlorobenzoyl)-2-nitrobenzenesulfonamide

In the title compound, C13H9ClN2O5S, the N—C bond in the C—SO2—NH—C segment has a gauche torsion with respect to the S=O bonds. The conformation between the N—H bond and the ortho-nitro group in the sulfonyl benzene ring is syn, and that between the C=O and the meta-Cl atom in the benzoyl ring is anti. The molecule is twisted at the S—N bond, with a torsion angle of 65.41 (38)°. The dihedral angle between the sulfonyl benzene ring and the –SO2—NH—C—O segment is 75.0 (1)°, and that between the sulfonyl and the benzoyl benzene ring is 89.1 (1)°. The crystal structure features inversion-related dimers linked by pairs of N—H⋯O(S) hydrogen bonds.

In the title compound, C 13 H 9 ClN 2 O 5 S, the N-C bond in the C-SO 2 -NH-C segment has a gauche torsion with respect to the S O bonds. The conformation between the N-H bond and the ortho-nitro group in the sulfonyl benzene ring is syn, and that between the C O and the meta-Cl atom in the benzoyl ring is anti. The molecule is twisted at the S-N bond, with a torsion angle of 65.41 (38) . The dihedral angle between the sulfonyl benzene ring and the -SO 2 -NH-C-O segment is 75.0 (1) , and that between the sulfonyl and the benzoyl benzene ring is 89.1 (1) . The crystal structure features inversion-related dimers linked by pairs of N-HÁ Á ÁO(S) hydrogen bonds.

Experimental
The conformation between the N-H and C═O bonds in the C-SO 2 -NH-C(O) segment is anti and the N-C bond in the segment has gauche torsion with respect to the S═O bonds ( Fig. 1), similar to that observed in N-(2-chlorobenzoyl)-2-nitrobenzenesulfonamide (I) (Suchetan et al., 2012). In the title compound, the conformation between the N-H bond and the ortho-nitro group in the sulfonyl benzene ring is syn, similar to that observed in (I). Further, the conformation of the C═O is anti to the meta-Cl atom in the benzoyl ring, similar to that observed between the C═O and the ortho-Cl atom in (I).
The molecule is twisted at the S-N bond with the torsional angle of 65.41 (38)°, compared to the value of -59.68 (17)° in (I).
The dihedral angle between the sulfonyl benzene ring and the -SO 2 -NH-C-O segment is 75.0 (1)°, compared to the value of 77.5 (1)° in (I). Furthermore, the dihedral angle between the sulfonyl and the benzoyl benzene rings is 89.1 (1)°, compared to the value of 71.2 (1)° in (I).
In the crystal structure two molecules each are linked by pairs of intermolecular N-H···O (S) hydrogen bonds into dimers that are located around centers of inversion ( Fig. 2 and Table 1).

Experimental
The title compound was prepared by refluxing a mixture of 3-chlorobenzoic acid (0.02 mole), 2-nitrobenzenesulfonamide (0.02 mole) and excess phosphorous oxychloride for 3 h on a water bath. The resultant mixture was cooled and poured into crushed ice. The solid, N-(3-chlorobenzoyl)-2-nitrobenzenesulfonamide, 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.
Rod like colourless single crystals of the title compound used in X-ray diffraction studies were obtained by slow evaporation of the solvent from its toluene solution at room temperature.

Refinement
The H atom of the NH group was 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).   View of the inversion-related dimers linked by pairs of N-H···O(S) hydrogen bonds (Hydrogen bonding is 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.