(E)-N′-(2-Chloro-5-nitrobenzylidene)-3-methoxybenzohydrazide monohydrate

In the hydrazone molecule of the title compound, C15H12ClN3O4·H2O, the two benzene rings form a dihedral angle of 3.6 (1)°. In the crystal structure, the solvent water molecules are involved in the formation of intermolecular N—H⋯O and O—H⋯N hydrogen bonds, which link the molecules into double ribbons extending along the b axis. Intermolecular π–π interactions between the aromatic rings [centroid–centroid distances = 3.712 (3) and 3.672 (3) Å] link these ribbons further into layers parallel to the ab plane.

In the hydrazone molecule of the title compound, C 15 H 12 ClN 3 O 4 ÁH 2 O, the two benzene rings form a dihedral angle of 3.6 (1) . In the crystal structure, the solvent water molecules are involved in the formation of intermolecular N-HÁ Á ÁO and O-HÁ Á ÁN hydrogen bonds, which link the molecules into double ribbons extending along the b axis. Intermolecularinteractions between the aromatic rings [centroid-centroid distances = 3.712 (3) and 3.672 (3) Å ] link these ribbons further into layers parallel to the ab plane.
In the hydrazone molecule of (I) , two benzene rings form a dihedral angle of 3.6 (1)°. In the crystal structure, the crystalline water molecules are involved in formation of intermolecular N-H···O and O-H···O hydrogen bonds (Table   2), which link the molecules into doubled ribbons extended along b axis (Fig. 2). Intermolecular π-π interactions ( Table 1) between the aromatic rings link further these ribbons into layers parallel to ab plane.

Experimental
The title compound was prepared by the condensation reaction of 2-chloro-5-nitrobenzaldehyde (1.0 mmol, 0.185 g) and 3-methoxybenzohydrazide (1.0 mmol, 0.166 g) in methanol (50 ml) at ambient temperature. Colourless block-shaped single crystals suitable for X-ray structural determination were obtained by slow evaporation of the solution for a few days.

Refinement
N-and O-bound H atoms were located from a difference Fourier map and refined with U iso (H) fixed to 0.08 and with the N-H distance restrained to 0.90 (1) Å and O-H distances restrained to 0.84 (1). The remaining H atoms were positioned geometrically and constrained to ride on their parent atoms, with C-H distances of 0.93-0.96 Å, and with U iso (H) = 1.2-1.5U eq (C). Fig. 1. The molecular structure of (I). Displacement ellipsoids are drawn at the 30% probability level. H atoms are shown as spheres of arbitrary radius. Hydrogen bond is shown as a dashed line.

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.