4-Methoxy-N′-(3-nitrobenzylidene)benzohydrazide

In the title compound, C15H13N3O4, the dihedral angle between the benzene rings is 3.1 (3)°. The molecule displays an E conformation about the C=N bond. In the crystal, molecules are linked via N—H⋯O hydrogen bonds, generating chains that propagate along the b-axis direction. There is also a C—H⋯O interaction present.


Jin-Long Hou and Ye Bi Comment
Hydrazones derived from the condensation reactions of hydrazides with aldehydes show excellent biological properties (Cukurovali et al., 2006;Karthikeyan et al., 2006;Kucukguzel et al., 2006). In the last few years, the crystal structure of a large number of hydrazone compounds have been reported (Hou, 2009;Hou, 2012;Lair et al., 2009;Fun et al., 2008;Zhang et al., 2009;Khaledi et al., 2008). Herein we report on the synthesis and crystal structure of the title compound, derived from the condensation reaction of 3-nitrobenzaldehyde and 4-methoxybenzohydrazide.
The molecular structure of the title compound is shown in Fig. 1. The dihedral angle between the two benzene rings is 3.1 (3)°. The molecule displays an E conformation about the C═N bond. All the bond lengths are within normal ranges (Allen et al., 1987).
In the crystal, molecules are linked via N-H···O hydrogen bonds (Table 1) generating chains along the b axis direction ( Fig. 2). There is also a C-H···O interaction present (Table 1).

Experimental
3-Nitrobenzaldehyde (1.0 mmol, 151 mg) and 4-methoxybenzohydrazide (1.0 mmol, 166 mg) were mixed and refluxed with stirring for two hours. Yellow single crystals were formed after slow evaporation of the solution in air for a week.

Refinement
The NH H atom was located in a difference Fourier map and refined with the N-H distance restrained to 0.90 (2) Å and U iso (H) = 0.08 Å 2 . The other H atoms were placed in calculated positions and constrained to ride on their parent atoms: C-H = 0.93 and 0.96 Å for CH and CH 3 H atoms, respectively, with U iso (H) = k × U eq (C), where k = 1.5 for CH 3 H atoms, and 1.2 for other H atoms. In the final cycles of refinement, in the absence of significant anomalous scattering effects, 929 Friedel pairs were merged and \Df " set to zero.  The molecular structure of the title molecule, with the atom numbering. The displacement ellipsoids are drawn at 30% probability level.

Figure 2
A view along the a axis of the crystal packing of the title compound, with the N-H···O hydrogen bonds shown as dashed lines (see Table 1 for details). Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles 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 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.