N-(3,5-Dimethylphenyl)-4-nitrobenzenesulfonamide

There are two independent molecules in the asymmetric unit of the title compound, C14H14N2O4S, in which the dihedral angles between the benzene rings are 56.22 (15) and 58.16 (14)°. In the crystal, N—H⋯Onitro hydrogen bonds link the molecules into zigzag chains running along the a-axis direction.

The asymmetric unit of the structure of (I) contains two crystallographically independent molecules, similar to that The dihedral angles between the sulfonyl and the anilino rings in the two molecules are 56.22 (15)° and 58.16 (14)°, compared to the values of 71.53 (7)° and 72.11 (7)° in (II).
The amide H-atom showed bifurcated intramolecular H-bonding with the O-atom of the ortho-nitro group in the sulfonyl benzene ring, generating S(7) motifs and the intermolecular H-bonding with the sulfonyl oxygen atom of the other molecule, generating C(4) motifs (Adsmond et al., 2001).
In the crystal, the intermolecular N-H···O (N) hydrogen bonds (Table 1) link the molecules into zigzag chains running along the a axis. Part of the crystal structure is shown in Fig. 2.

Experimental
The title compound was prepared by treating 4-nitrobenzenesulfonylchloride with 3,5-dimethylaniline 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-(3,5-dimethylphenyl)-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 colourless 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, methyl C-H = 0.96 Å. The amino H atoms were 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 (C-aromatic, N) or 1.5 U eq (C-methyl).   Molecular packing of the title compound with hydrogen bonding shown as dashed lines.

N-(3,5-Dimethylphenyl)-4-nitrobenzenesulfonamide
Crystal data C 14 H 14 N 2 O 4 S M r = 306.33 Orthorhombic, Pna2 1 Hall symbol: P 2c -2n a = 14.708 (1)  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.