1-(But-2-enylidene)-2-(2-nitrophenyl)hydrazine

The molecule of the title Schiff base compound, C10H11N3O2, adopts an E geometry with respect to the C=N double bond. The molecule is roughly planar, with the largest deviation from the mean plane being 0.111 (2) Å, The enylidene-hydrazine group is, however, slightly twisted with respect to the phenyl ring, making a dihedral angle of 6.5 (3)°. An intramolecular N—H⋯O hydrogen bond may be responsible for the planar conformation. An intermolecular N—H⋯O hydrogen bond links two molecules around an inversion center, building a pseudo dimer.

The molecule of the title Schiff base compound, C 10 H 11 N 3 O 2 , adopts an E geometry with respect to the C N double bond. The molecule is roughly planar, with the largest deviation from the mean plane being 0.111 (2) Å , The enylidenehydrazine group is, however, slightly twisted with respect to the phenyl ring, making a dihedral angle of 6.5 (3) . An intramolecular N-HÁ Á ÁO hydrogen bond may be responsible for the planar conformation. An intermolecular N-HÁ Á ÁO hydrogen bond links two molecules around an inversion center, building a pseudo dimer.

Comment
The chemistry of Schiff base has attracted a great deal of interest in recent years. These compounds play an important role in the development of various proteins and enzymes (Kahwa et al., 1986;Santos et al., 2001). As part of our in the study of the coordination chemistry of Schiff bases, we synthesized the title compound and determined its crystal structure.
The molecule is roughly planar with the largest deviation from the mean plane being -0.111 (2) Å at O1 (Fig. 1). The enylidene-hydrazine group is however slightly twisted with respect to the phenyl ring making a dihedral angle of 6.5 (3)° .
Intramolecular N-H···O bond may be responsible for the planar conformation whereas intermolecular N-H···O links two molecules around the inversion center buiding a pseudo dimer (Table 1, Fig. 2).
Experimental 2-Nitrophenylhydrazine (1 mmol, 0.153 g) was dissolved in anhydrous ethanol (15 ml), The mixture was stirred for several minitutes at 351 K, but-2-enal (1 mmol, 0.070 g) in ethanol (8 mm l) was added dropwise and the mixture was stirred at refluxing temperature for 2 h. The product was isolated and recrystallized from methanol, red single crystals of (I) was obtained after 3 d.

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 > σ(F 2 ) is used only for calculating Rfactors(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.