(1E,2E)-1,2-Bis[1-(3-nitrophenyl)ethylidene]hydrazine

The asymmetric unit of the title compound, C16H14N4O4, contains one half-molecule of (nitrophenyl)ethanimine and the complete molecule is generated by a crystallographic inversion centre. The molecule has an E conformation with respect to each C=N double bond. The central C=N—N=C plane is twisted from the benzene rings with a dihedral angle of 24.76 (11)°. In the crystal, C—H⋯O interactions link the molecules to form sheets that lie parallel to (10-4).

The asymmetric unit of the title compound, C 16 H 14 N 4 O 4 , contains one half-molecule of (nitrophenyl)ethanimine and the complete molecule is generated by a crystallographic inversion centre. The molecule has an E conformation with respect to each C N double bond. The central C N-N C plane is twisted from the benzene rings with a dihedral angle of 24.76 (11) . In the crystal, C-HÁ Á ÁO interactions link the molecules to form sheets that lie parallel to (104).
Owing to our medicinal chemistry research on hydrazones, we previously reported the synthesis and crystal structures of some hydrazone derivatives Fun, Nilwanna et al., 2011;Jansrisewangwong et al., 2010;Nilwanna et al., 2011). The title compound was synthesized to study for antibacterial activity and fluorescence properties in order to get more detail on the structural activity relationship through comparing with other closely related compounds.

Experimental
The title compound was synthesized by mixing a solution (1:2 molar ratio) of hydrazine hydrate (0.10 ml, 2 mmol) and 3nitroacetophenone (0.66 g, 4 mmol) in ethanol (20 ml). The resulting solution was refluxed for 4 h, yielding the yellow crystalline solid. The resultant solid was filtered off and washed with methanol. Yellow block-shaped single crystals of the title compound suitable for X-ray structure determination were recrystalized from acetone by slow evaporation of the solvent at room temperature over several days (m.p. 469-471 K).

Refinement
All the H atoms were positioned geometrically and refined using a riding model with C-H = 0.93 and 0.96 Å. The U iso values were constrained to be 1.5U eq of the carrier atom for methyl H atoms and 1.2U eq for the remaining H atoms. A rotating group model was used for the methyl groups.

Figure 1
The structure of the title compound, showing 50% probability displacement ellipsoids. H atoms are shown as spheres of arbitrary radius.   where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.21 e Å −3 Δρ min = −0.18 e Å −3 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.