4-(2-Iodobenzenesulfonamido)benzoic acid monohydrate

In the molecule of the title compound, C13H10INO4S·H2O, the coordination around the S atom is distorted tetrahedral. The aromatic rings are oriented at a dihedral angle of 74.18 (17)°. Intramolecular C—H⋯O hydrogen bonds result in the formation of non-planar five- and six-membered rings, which adopt envelope and twist conformations, respectively. In the crystal structure, intermolecular N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds link the molecules. π–π Contacts between the phenyl rings [centroid–centroid distance = 3.726 (3) Å] may further stabilize the structure. There is also a C—H⋯π interaction.

In the molecule of the title compound, C 13 H 10 INO 4 SÁH 2 O, the coordination around the S atom is distorted tetrahedral. The aromatic rings are oriented at a dihedral angle of 74.18 (17) . Intramolecular C-HÁ Á ÁO hydrogen bonds result in the formation of non-planar five-and six-membered rings, which adopt envelope and twist conformations, respectively. In the crystal structure, intermolecular N-HÁ Á ÁO, O-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds link the molecules. -Contacts between the phenyl rings [centroid-centroid distance = 3.726 (3) Å ] may further stabilize the structure. There is also a C-HÁ Á Á interaction.

Comment
The title compound belongs to the sulfonamide family of the organic compounds. This class of compounds is used as antibecterial agent. The halogenated sulfonamide is used as an inhibitor for the growth of multidrug resistant MCF-7/ADR cancer cells (Medina et al., 1999). In continuation to our researches with sulfonamides (Arshad et al., 2008a,b), the title compound has been prepared, which will be utilized for the syntheses of biologically active heterocyclic molecules with thiazine moiety, and we report herein its crystal structure.
In the title compound, (I), (Fig 1), 2-iodophenyl and p-aminobenzoic acid moieties are connected through the SO 2 group.
The structure of (I) differs from 4-(tosylamino)benzoic acid, (II) (Nan & Xing, 2006), mainly due to the attachment of the iodo group at ortho position instead of methyl group at the para-position. The coordination around the S atom is a distorted tetrahedral. Rings A(C1-C6) and B(C7-C12) are oriented at a dihedral angle of 74.18 (17)°. The intramolecular C-H···O hydrogen bonds (Table 1) result in the formations of nonplanar five-and six-membered rings: C (S1/O1/C1/C6/H6) and D (S1/O1/N1/C7/C12/H12). Ring C adopts envelope conformation with O1 atom displaced by -0.172 (3) Å from the plane of the other rings atoms, while ring D has twisted conformation.
In the crystal structure, intermolecular N-H···O, O-H···O and C-H···O hydrogen bonds (Table 1) link the molecules (Fig.   2), in which they may be effective in the stabilization of the structure. The π-π contact between the phenyl rings, Cg1-Cg1 i [symmetry code: (i) -x, -y, -z, where Cg1 is centroid of the ring A (C1-C6)] may further stabilize the structure, with centroidcentroid distance of 3.726 (3) Å. There also exists a C-H···π interaction (Table 1).

Experimental
The title compound was synthesized according to a literature method (Deng & Mani, 2006). 4-Aminobenzoic acid (0.23 g, 1.67 mmol) was suspended in distilled water (10 ml) in a round bottom flask. The pH of the solution was adjusted to 8-9 using Na 2 CO 3 (1 M). Then, 2-iodobenzene sulfonyl chloride (0.5 g, 1.66 mmol) was added, and stirred at room temperature. The reaction pH was maintained at 8-9. Completion of reaction was indicated by the dissolvation of the suspended 2-iodobenzene sulfonyl chloride. Then, pH was adjusted to 2-3 using HCl (2 N), the precipitate formed was filtered, washed with distilled water, and then recrystalyzed in methanol.

Special details
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles 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 Rfactors(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.