(E)-3-Bromo-N′-(5-bromo-2-hydroxybenzylidene)benzohydrazide

The title compound, C14H10Br2N2O2, was synthesized by the reaction of 5-bromosalicylaldehyde with an equimolar quantity of 3-bromobenzohydrazide in methanol. The dihedral angle between the two benzene rings is 10.5 (4)°. In the crystal structure, molecules are linked through intermolecular N—H⋯O hydrogen bonds to form chains parallel to the c axis, and an intramolecular O—H⋯N interaction also occurs.

The title compound, C 14 H 10 Br 2 N 2 O 2 , was synthesized by the reaction of 5-bromosalicylaldehyde with an equimolar quantity of 3-bromobenzohydrazide in methanol. The dihedral angle between the two benzene rings is 10.5 (4) . In the crystal structure, molecules are linked through intermolecular N-HÁ Á ÁO hydrogen bonds to form chains parallel to the c axis, and an intramolecular O-HÁ Á ÁN interaction also occurs.

Comment
We have recently reported some transition metal complexes with Schiff base ligands (Cao, 2007a,b) and a hydrazone compound (Yang et al., 2008). We report herein the crystal structure of the title compound, (I), derived from the reaction of 5-bromosalicylaldehyde with an equimolar quantity of 3-bromobenzohydrazide in methanol.

Experimental
The compound was prepared by refluxing equimolar quantities of 5-bromosalicylaldehyde with 3-bromobenzohydrazide in methanol. Colorless block-like crystals were formed when the solution was evaporated in air for about a week.

Refinement
H2 was located in a difference Fourier map and refined isotropically, with the N-H distance restrained to 0.90 (4) 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, the O-H distance of 0.82 Å, and with U iso (H) set at 1.2U eq (C) and 1.5U eq (O).

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.