N′-(2,4-Dichlorobenzylidene)-3-methoxybenzohydrazide

There are two independent molecules in the asymmetric unit of the title compound, C15H12Cl2N2O2. The dihedral angle between the two benzene rings is 27.6 (4)° in one molecule and 16.4 (4)° in the other. Both molecules adopt an E configuration about the C=N bonds. In the crystal structure, molecules are linked through intermolecular N—H⋯O hydrogen bonds, forming chains in the a-axis direction.

There are two independent molecules in the asymmetric unit of the title compound, C 15 H 12 Cl 2 N 2 O 2 . The dihedral angle between the two benzene rings is 27.6 (4) in one molecule and 16.4 (4) in the other. Both molecules adopt an E configuration about the C N bonds. In the crystal structure, molecules are linked through intermolecular N-HÁ Á ÁO hydrogen bonds, forming chains in the a-axis direction.   Table 1 Hydrogen-bond geometry (Å , ).

Related literature
The Schiff base compounds show excellent biological properties (Jeewoth et al., 1999;Ren et al., 2002;Eltayeb et al., 2008;Sinha et al., 2008). Recently, the author has reported a few Schiff bases (Ren, 2009a,b). In this paper, the title new Schiff base compound is reported.
In the crystal structure, molecules are linked through intermolecular N-H···O and O-H···O hydrogen bonds (Table 1), forming chains toward the a direction (Fig. 2).

Experimental
All the starting materials were obtained with AR grade from Lancaster. 2,4-Dichlorobenzaldehyde (1.0 mmol, 174.0 mg) and 3-methoxybenzohydrazide (1.0 mmol, 166.2 mg) were refluxed in a 30 ml me thanol solution for 30 min to give a clear colorless solution. Colorless needle-shaped single crystals of the compound were obtained by slow evaporation of the solution for a week at room temperature.

Refinement
H atoms were constrained to ideal geometries, with d(C-H) = 0.93 Å, d(N-H) = 0.86 Å, and with U iso (H) = 1.2U eq (C,N) and 1.5U eq (C methyl ). The resolution is 22.92°, and the sin(theta)/Lambda < 0.6, which is caused by the weak diffraction of the crystal.

Data collection
Bruker SMART CCD area-detector diffractometer 4120 independent reflections

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.