(E)-N′-(2,4-Dichlorobenzylidene)-3-nitrobenzohydrazide

The title compound, C14H9Cl2N3O3, was prepared by the reaction of 3-nitrobenzohydrazide with 2,4-dichlorobenzaldehyde. The molecule adopts an E configuration about the C=N bond. The dihedral angle between the two benzene rings is 4.6 (2)°. In the crystal, the hydrazone molecules are linked through intermolecular N—H⋯O hydrogen bonds, forming chains along the c axis.

The O2/N3/O3 plane forms a dihedral angle of 8.9 (2)° with the C9···C14 benzene ring. The bond lengths and angles are comparable to those found in the hydrazone compounds cited above. In the crystal structure, the hydrazone molecules are linked through intermolecular N-H···O hydrogen bonds (Table 1), to form one-dimensional chains along the c axis, as shown in Fig. 2.

Experimental
The reaction of 3-nitrobenzohydrazide (0.181 g, 1 mmol) with 2,4-dichlorobenzaldehyde (0.174 g, 1 mmol) in 50 ml methanol at room temperature afforded the title compound. Yellow block-shaped single crystals were formed by slow evaporation of the clear solution in air.

Refinement
The amino H atom was located in a difference Fourier map and refined with N-H = 0.90 (1) Å, and U iso = 0.08 Å 2 . Other H atoms were positioned geometrically (C-H = 0.93 Å) and refined as riding with U iso (H) = 1.2U eq (C). Fig. 1. The molecular structure of the title compound showing 30% probability displacement ellipsoids and the atomic numbering.

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 supplementary materials sup-3 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 > 2sigma(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.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )