2-Chloro-N′-[(E)-(2-methoxy-1-naphthyl)methylene]benzohydrazide

In the molecule of the title Schiff base compound, C19H15ClN2O2, the dihedral angle between the benzene ring and naphthyl ring system is 77.1 (2)°. In the crystal structure, centrosymmetrically related molecules are linked into dimers through pairs of intermolecular N–H⋯O hydrogen bonds, generating rings of graph set R 2 2(8).

In the molecule of the title Schiff base compound, C 19 H 15 ClN 2 O 2 , the dihedral angle between the benzene ring and naphthyl ring system is 77.1 (2) . In the crystal structure, centrosymmetrically related molecules are linked into dimers through pairs of intermolecular N-HÁ Á ÁO hydrogen bonds, generating rings of graph set R 2 2 (8).
Financial support from Jiaying University Research Fund is gratefully acknowledged.
In the title compound ( Fig. 1), the dihedral angle between the benzene ring and the naphthyl ring system is 77.1 (2) °.
The molecule adopts an E configuration about the C═N bond. All the bond lengths are within normal values (Allen et al., 1987). In the crystal structure (Fig. 2), centrosymmetrically related molecules are linked into dimers through intermolecular N-H···O hydrogen bonds (Table 1), forming rings of graph set R 2 2 (8) (Etter et al., 1990;Bernstein et al., 1995).
Experimental 2-Methoxy-1-naphthylaldehyde (0.1 mmol, 18.6 mg) and 2-chlorobenzohydrazide (0.1 mmol, 12.6 mg) were dissolved in a methanol solution (20 ml). The mixture was stirred at reflux for 10 min to give a clear colourless solution. Colourless block-like crystals of the compound were formed by slow evaporation of the solvent over several days.

Refinement
Atom H2 was located from a difference Fourier map and refined isotropically, with U iso restrained to 0.08Å 2 . Other H atoms were constrained to ideal geometries, with C-H = 0.93-0.96 Å, and with U iso (H) = 1.2U eq (C) or 1.5U eq (C) for methyl H atoms.
Figures Fig. 1. The molecular structure of the title compound, showing the atom-numbering scheme. Displacement ellipsoids are 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 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.