(E)-4-Amino-N′-(3-nitrobenzylidene)benzohydrazide

In the title compound, C14H12N4O3, the dihedral angle between the benzene rings is 7.6 (4)°. In the crystal, infinite sheets linked by N—H⋯O and bifurcated N—H⋯(O,N) hydrogen bonds propagate in the (10-1) plane, in which R 4 4(36) loops are apparent. Neighbouring layers may interact by way of very weak π–π stacking interactions [centroid–centroid distances = 3.9329 (13) and 4.0702 (13) Å].


Shu-Qing Xu Comment
As an extension of recent studies of hydrazone Schiff bases, (Cao, 2009;Zhou & Yang, 2010), the title compound was prepared and characterized.
As shown in Fig. 1, the asymmetric unit of the title compound, (I), contains one independent molecule displaying an E configuration with respect to its C═N double bond. The dihedral angle between the two benzene rings is 7.6 (4) °. The bond lengths and angles are as expected for a compound of this type and agree with the other ligands belonging to the hydrazone series. The C8═N3 and C7═O1 bond lengths of 1.283 (2) and 1.228 (2) Å, respectively, conform to the values for double bonds. Whereas the C1-N1, C8-N3, C11-N4 and N2-N3 [1.385 (2), 1.360 (2), 1.466 (2) and 1.378 (2) Å, respectively] bond lengths correspond to a single bond. In the crystal packing, it is noted that one of amino H (H1A) and amide H2 are involved in forming intermolecular N-H···O and N-H···N hydrogen bonds, which link the molecules into a R 4 4 (36) graph-set notation ( Fig. 2 and Table 1). These rings form an alternating sequence, in turn, linking the molecules into a two-dimensional supramolecular sheet structure parallel to (101). Neighboring layers are further interacting with each other through weak π-π stacking interactions [centroid to centroid distances of the benzene C1/C6 and C9/C14 rings are 3.93 (6) and 4.07 (6) Å].
The mixture was stirred for 6 hours at room temperature to give a yellow solution. Yellow prisms were formed by gradual evaporation of the solvent over a period of 5 days at room temperature.

Refinement
H-atoms were placed in calculated positions (C-H = 0.93 and N-H = 0.86-0.89 Å) and were included in the refinement in the riding model approximation, with U iso (H) set to 1.2U eq (C or N).  The molecular structure of the title compound, with displacement ellipsoids at the 30% probability level.

Figure 2
Crystal packing in the title compound where molecules are linked via N-H···O hydrogen bonds (dashed lines). Except for those involved in hydrogen-bonding interactions, H atoms have been omitted for clarity.

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.