4-Hydroxy-N′-(3-nitrobenzylidene)benzohydrazide

The title compound, C14H11N3O4, was obtained by a condensation reaction between 3-nitrobenzaldehyde and 4-hydroxybenzohydrazide. The whole molecule is approximately planar, with a dihedral angle of 9.2 (3)° between the benzene rings. The molecule displays an E conformation about the C=N bond. In the crystal, molecules are linked via N—H⋯O, O—H⋯O and O—H⋯N hydrogen bonds, generating sheets parallel to the bc plane.

The title compound, C 14 H 11 N 3 O 4 , was obtained by a condensation reaction between 3-nitrobenzaldehyde and 4hydroxybenzohydrazide. The whole molecule is approximately planar, with a dihedral angle of 9.2 (3) between the benzene rings. The molecule displays an E conformation about the C N bond. In the crystal, molecules are linked via N-HÁ Á ÁO, O-HÁ Á ÁO and O-HÁ Á ÁN hydrogen bonds, generating sheets parallel to the bc plane.

Comment
Hydrazones derived from the condensation reactions of hydrazides with aldehydes show excellent biological properties (Cukurovali et al., 2006;Karthikeyan et al., 2006;Kucukguzel et al., 2006). In the last few years, a great deal of hydrazone compounds have been reported for their crystal structures see (Hou, 2009;Mohd Lair et al., 2009;Fun et al., 2008;Zhang et al., 2009;Khaledi et al., 2008). In this paper, the title new compound, derived from the condensation reaction of 3-nitrobenzaldehyde and 4-hydroxybenzohydrazide was synthesized and structurally characterized.
The molecular structure of the compound is shown in Fig. 1. The whole molecule of the compound is approximately coplanar, with the dihedral angle between the mean planes through the two benzene rings of 9.2 (3)°. The molecule displays an E configuration about the C=N bond. All the bond lengths are within normal ranges (Allen et al., 1987). In the crystal, molecules are linked via N-H···O hydrogen bonds (Table 1), generating two-dimensional sheets (Fig. 2). with stirring for two hours. Yellow single crystals were formed after slow evaporation of the solution in air for a week.

Refinement
H2A was located in a difference Fourier map and refined isotropically, with the N-H distance restrained to 0.90 (1) Å.
The other H atoms were placed in idealized positions and constrained to ride on their parent atoms with C-H distances of 0.93 Å, O-H distance of 0.82 Å, and with U iso (H) set at 1.2U eq (C) and 1.5U eq (O).

Figure 2
Molecular packing diagram, viewed along the b axis. Hydrogen bonds are shown as dashed lines.

Special details
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.