N-(3-Chlorophenyl)-3-methylbenzamide hemihydrate

In the title compound, C14H12ClNO·0.5H2O, the N—H bond is in an anti conformation to the C=O bond. The two aromatic rings make a dihedral angle of 49.5 (1)°. The water molecule lies on a twofold rotation axis. In the crystal, intermolecular N—H⋯O and O—H⋯O hydrogen bonds connect the molecules into a three-dimensional network.

In the title compound, C 14 H 12 ClNOÁ0.5H 2 O, the N-H bond is in an anti conformation to the C O bond. The two aromatic rings make a dihedral angle of 49.5 (1) . The water molecule lies on a twofold rotation axis. In the crystal, intermolecular N-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds connect the molecules into a three-dimensional network.   Table 1 Hydrogen-bond geometry (Å , ).

Comment
In the present work, as part of a study of the substituent effects on the crystal structures of benzanilides (Gowda et al., 2008a,b, Rodrigues et al., 2010, the structure of N-(3-chlorophenyl)3-methylbenzamide hydrate (I) has been determined. In the structure, the conformations of the N-H and C=O bonds are anti to each other ( Fig. 1), similar to those ob- The two aromatic rings make a dihedral angle of 49.5 (1)°. The central amide group -NH-C(=O)-is twisted by 35.1 (1)°a nd 15.9 (1)° out of the planes of the 3-methylphenyl and 3-chlorophenyl ring, respectively. The molecular structure is stabilized by the C9-H9···O1 intramolecular hydrogen bond (Table 1). In the crystal, the water molecule lies on a twofold rotation axis.
Intermolecular N-H···O and O-H···O hydrogen bonds connect the molecules into a three-dimensional network (Fig.2).
The water O2w oxygen lies on a twofold rotation axis 0,y,1/4 and its hydrogen atoms are related by the symmetry -x, y, 1/2 -z.

Experimental
The title compound was prepared according to the literature method (Gowda et al., 2008a,b). The purity of the compound was checked by determining its melting point. It was characterized by recording its infrared and NMR spectra. Single crystals of the title compound used in X-ray diffraction studies were obtained from a slow evaporation of its ethanolic solution in the presence of a few drops of water, at room temperature.

Refinement
The C-and N-bound hydrogen atoms were positioned with idealized geometry using a riding model with C-H = 0.93 Å or 0.96 Å and N-H = 0.86 Å. The coordinates of the water hydrogen atom were refined. The U iso (H) values were set at 1.2U eq (C aromatic, N, O) and 1.5U eq (C methyl ). The C14-methyl group exhibits orientational disorder in the positions of H atoms. The two sets of methyl hydrogen atoms were refined with occupancies of 0.52 (9)) and 0.48 (9).

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 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.