2-Chloro-N′-(2,4-dichlorobenzylidene)benzohydrazide

The title Schiff base compound, C14H9Cl3N2O, exists in a trans configuration with respect to the C=N bond and the dihedral angle between the two benzene rings is 13.5 (2)°. In the crystal, intermolecular N—H⋯O hydrogen bonds link adjacent molecules into extended C(4) chains propagating along the c-axis direction.

The title Schiff base compound, C 14 H 9 Cl 3 N 2 O, exists in a trans configuration with respect to the C N bond and the dihedral angle between the two benzene rings is 13.5 (2) . In the crystal, intermolecular N-HÁ Á ÁO hydrogen bonds link adjacent molecules into extended C(4) chains propagating along the c-axis direction.
The molecule exists in a trans configuration with respect to the acyclic C═N bond. The molecule of the compound is distorted, with the dihedral angle between the two benzene rings of 13.5 (2)°.
In the crystal structure, intermolecular N-H···O hydrogen bonds link adjacent molecules into extended chains along the c axis (Table 1 and Fig. 2).
Experimental 2,4-Dichlorobenzaldehyde (1.0 mmol, 175 mg) and 2-chlorobenzohydrazide (1.0 mmol, 170 mg) were dissolved in a methanol solution (30 ml). The mixture was stirred for 30 min at room temperature. The resulting solution was left in air for a few days, yielding colourless blocks of (I).

Refinement
H2 attached to N2 was located in a difference map and refined with N-H distance restrained to 0.90 (1)Å. The remaining H atoms were positioned geometrically, with C-H distances of 0.93 Å, and refined using a riding model, with U iso (H) = 1.2U eq (C). Fig. 1. The molecular structure of (I), with ellipsoids drawn at the 30% probability level.

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 )