2-Chloro-N-(4-methoxybenzoyl)benzenesulfonamide

In the title compound, C14H12ClNO4S, the dihedral angle between the aromatic rings is 82.07 (1)° and the dihedral angle between the planes defined by the S—N—C=O fragment and the sulfonyl benzene ring is 82.46 (3)°. In the crystal, the molecules are linked into C(4) chains running along [001] by strong N—H⋯O hydrogen bonds. A C—H⋯O interaction reinforces the [001] chains: its graph-set symbol is C(7). The chains are cross-linked into (100) sheets by further C—H⋯O interactions as C(6) chains along [001]. The structure also features weak π–π stacking interactions [centroid–centroid distances = 3.577 (1) and 3.8016 (1) Å].

In the title compound, C 14 H 12 ClNO 4 S, the dihedral angle between the aromatic rings is 82.07 (1) and the dihedral angle between the planes defined by the S-N-C=O fragment and the sulfonyl benzene ring is 82.46 (3) . In the crystal, the molecules are linked into C(4) chains running along [001] by strong N-HÁ Á ÁO hydrogen bonds. A C-HÁ Á ÁO interaction reinforces the [001] chains: its graph-set symbol is C(7). The chains are cross-linked into (100) sheets by further C-HÁ Á ÁO interactions as C(6) chains along [001]. The structure also features weakstacking interactions [centroid-centroid distances = 3.577 (1) and 3.8016 (1) Å ].

Synthesis and crystallization
The title compound (I) was prepared by refluxing a mixture of 4-methoxybenzoic acid, 2-chlorobenzenesulfonamide and phosphorous oxychloride (POCl 3 ) 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 compound obtained was filtered and later dried (Melting point: 445 K).
Colorless prisms of (I) were obtained from a slow evaporation of its aqueous methanolic solution at room temperature.

Refinement
The H atom of the NH group was located in a difference map and later refined freely. The other H atoms were positioned with idealized geometry using a riding model with C-H = 0.93-0.96 Å. All H atoms were refined with isotropic displacement parameters (set to 1.2-1.5 times of the U eq of the parent atom).

Results and discussion
In I, the dihedral angle between the two aromatic rings is 82.07 (1)°. Compared to this, the dihedral angle is 73.3 (1)° in N-(benzoyl)-2-chlorobenzenesulfonamide (II, Gowda et al., 2010a), 85.7 (1) Gowda et al., 2010b) and 85.4 (1)° in N-(4-nitrobenzoyl)-2-chlorobenzenesulfonamide (V, Suchetan et al., 2011b). This shows that introducing a substituent into the para position of the benzoyl ring of II correlates with a increase of the dihedral angle between the aromatic rings. Further, the molecule is twisted at the S atom, the dihedral angle between the planes defined by the S-N-C=O segment in the central chain and the sulfonyl benzene ring being 82.46 (3)°.
In the crystal structure, the molecules are linked into C(4) chains running along [001] through strong N1-H1···O2 hydrogen bonds (Figure 2). The molecules are further linked into one another through C3-H3···O1 ( Figure 3) and C9-H9···O2 ( Figure 4) interactions into C(6) and C(7) chains running along [001]. The structure is further stabilized by two alternate π-π interactions, Cg(methoxyphenyl)-Cg(methoxyphenyl) and Cg(chlorophenyl)-Cg(chlorophenyl) distances being respectively 3.577 (1)Å and 3.8016 (1)Å.         π-π stacking interactions observed in the crystal structure of I. 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.