(E)-1-(2,4-Dinitrophenyl)-2-[1-(3-nitrophenyl)ethylidene]hydrazine

In the asymmetric unit of the title compound, C14H11N5O6, there are three crystallographically independent molecules with similar conformations but some differences in bond angles. The molecules are slightly twisted with the dihedral angles between the benzene rings being 10.02 (14), 8.41 (15) and 1.40 (14)°. In each molecule, an intramolecular N—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, molecules are linked by weak C—H⋯O interactions into a three-dimensional network. π–π interactions with centroid–centroid distances of 3.5635 (17)–3.8273 (18) Å are observed.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 et al., 2010;Krishnamoorthy et al., 2011;Raja et al., 2012;Sathyadevi et al., 2012). In our on-going research on bioactivity of hydrazones, the title compound (I) was synthesized and evaluated for antioxidant activity by DPPH scavenging (Molyneux, 2004) and was found to be weakly active with 30% inhibition. It was also screened for antibacterial activity and found to be inactive. Herein we report the synthesis and crystal structure of (I).
In the crystal structure (Fig. 2), the molecules are linked by C-H···O weak interactions (Table 1) into a threedimensional network. π-π interactions were presented with the distances of Cg1···Cg6

Experimental
The title compound (I) was synthesized by dissolving 2,4-dinitrophenylhydrazine (0.40 g, 2 mmol) in ethanol (10.00 ml) and H 2 SO 4 (conc.) (98%, 0.50 ml) was slowly added with stirring. 3-Nitroacetophenone (0.35 g, 2 mmol) in ethanol (10.00 ml) was then added to the solution with continuous stirring. The solution was refluxed for 1 hr yielding an yellow solid which 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 ethanol by slow evaporation of the solvent at room temperature over several days (m.p. 507-508 K).

Refinement
All H atoms were positioned geometrically and allowed to ride on their parent atoms, with N-H = 0.88 Å, C-H = 0.95 Å for aromatic and 0.98 Å for CH 3 atoms. The U iso (H) 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.   The crystal packing diagram of the title compound viewed approximately along the c axis. Hydrogen bonds are shown as dashed lines.

(E)-1-(2,4-Dinitrophenyl)-2-[1-(3-nitrophenyl)ethylidene]hydrazine
Crystal data (1) (Cosier & Glazer, 1986) operating at 120.0 (1) K. Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > 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 )