(E)-3-Nitro-N′-(3-nitrobenzylidene)benzohydrazide

In the title compound, C14H10N4O5, the molecule exists in a trans conformation with respect to the methylidene unit. The dihedral angle between the benzene rings is 9.8 (2)°. In the crystal, molecules are linked through N—H⋯O hydrogen bonds to form chains along the c axis.

In the title compound, C 14 H 10 N 4 O 5 , the molecule exists in a trans conformation with respect to the methylidene unit. The dihedral angle between the benzene rings is 9.8 (2) . In the crystal, molecules are linked through N-HÁ Á ÁO hydrogen bonds to form chains along the c axis.   Table 1 Hydrogen-bond geometry (Å , ). (4) 159 (4) Symmetry code: (i) x; Ày þ 3 2 ; z þ 1 2 .

Comment
In recent years, hydrazone compounds have attracted much attention due to their syntheses and crystal structures (Hashemian et al., 2011;Lei, 2011;Shalash et al., 2010). As a continuation of our work on such compounds (Li, 2011a,b), the author reports herein on the crystal structure of the new title hydrazone compound.
The title compound ( Fig. 1) exists in a trans configuration with respect to the methylidene unit. The dihedral angle between the C1-C6 and C9-C14 benzene rings of the molecule is 9.8 (2)°. The N1/O1/O2 and N4/O4/O5 nitro groups are tilted by 11.0 (2) and 15.5 (2)° with respect to the attached benzene rings. In the crystal, molecules are linked through N-H···O hydrogen bonds (Table 1) to form chains along the c axis ( Fig. 2).

Experimental
A mixture of 3-nitrobenzaldehyde (0.151 g, 1 mmol) and 3-nitrobenzohydrazide (0.181 g, 1 mmol) in 30 ml of ethanol containing few drops of acetic acid was refluxed for about 1 h. On cooling to room temperature, a solid precipitate was formed. The solid was filtered and then recrystallized from methanol. Yellow crystals, suitable for X-ray diffraction analysis, were obtained by slow evaporation of the solvent.

Refinement
The amino H atom was located from a difference Fourier map and refined isotropically with the N-H distance restrained to 0.90 (1) Å. The remaining H-atoms were positioned geometrically and refined using a riding model, with C-H = 0.93 Å, and with U iso (H) set to 1.2U eq (C).  The molecular structure of the title compound, showing displacement ellipsoids drawn at the 30% probability level. 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq N1 0.8246 (4