N′-(5-Bromo-2-methoxybenzylidene)-2-hydroxybenzohydrazide

The title Schiff base compound, C15H13BrN2O3, is derived from the condensation of 5-bromo-2-methoxybenzaldehyde with 2-hydroxybenzohydrazide in an ethanol solution. The dihedral angle between the two aromatic rings is 6.9 (9)°. The methoxy group is coplanar with the attached ring [C—O—C—C = 3.1 (12)°]. An intramolecular N—H⋯O hydrogen bond is observed. In the crystal structure, the molecules are linked into chains along the [001] direction by intermolecular O—H⋯N, O—H⋯O and C—H⋯O hydrogen bonds.

The title Schiff base compound, C 15 H 13 BrN 2 O 3 , is derived from the condensation of 5-bromo-2-methoxybenzaldehyde with 2-hydroxybenzohydrazide in an ethanol solution. The dihedral angle between the two aromatic rings is 6.9 (9) . The methoxy group is coplanar with the attached ring [C-O-C-C = 3.1 (12) ]. An intramolecular N-HÁ Á ÁO hydrogen bond is observed. In the crystal structure, the molecules are linked into chains along the [001] direction by intermolecular O-HÁ Á ÁN, O-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds.

Comment
As part of our investigation of the crystal structures of Schiff bases derived from the condensation of aldehydes with benzohydrazides (Lu et al., 2008a,b,c), we report here the crystal structure of the title new Schiff base compound.
In the title molecule ( Fig. 1), the bond lengths have normal values (Allen et al., 1987), and are comparable to those observed in similar compounds (Nie, 2008;He, 2008;Shi et al., 2007). The methoxy group is coplanar with the attached ring [C15-O1-C2-C3 = 3.1 (12)°]. The dihedral angle between the two aromatic rings is 6.9 (9)°, indicating that the molecule is approximately planar. An intramolecular N-H···O hydrogen bond is observed in the molecule (Table 1).
In the crystal structure, the molecules are linked into chains ( (Table 1).

Experimental
The title compound was prepared by the Schiff base condensation of 5-bromo-2-methoxybenzaldehyde (0.1 mol) and 2-hydroxybenzohydrazide (0.1 mol) in 95% ethanol (50 ml). The excess ethanol was removed by distillation. The colourless solid obtained was filtered and washed with ethanol. Single crystals suitable for X-ray diffraction were obatined by slow evaporation of a 95% ethanol solution at room temperature.

Refinement
The imino H atom was located in a difference map and refined with a N-H distance restraint of 0.90 (1) Å and a fixed U iso of 0.08 Å 2 . The other H atoms were positioned geometrically (C-H = 0.93-0.96 Å, O-H = 0.82 Å) and refined using a riding model, with U iso (H) = 1.2U eq (C) and 1.5U eq (C methyl and O). A rotating group model was used for methyl and hydroxyl groups.The ratio of observed to unique reflections is low (37%), which is due to the poor diffraction quality of the crystal. Fig. 1. The molecular structure of the title compound, showing 30% probability displacement ellipsoids and the atom-numbering scheme. The intramolecular hydrogen bond is shown by a dashed line.

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.