(E)-N′-(3,5-Dibromo-2-hydroxybenzylidene)-2-methoxybenzohydrazide

The title compound, C15H12Br2N2O3, was synthesized by the reaction of 3,5-dibromo-2-hydroxybenzaldehyde with an equimolar quantity of 2-methoxybenzohydrazide in methanol. The dihedral angle between the two benzene rings is 3.4 (2)° and intramolecular O—H⋯N and N—H⋯O hydrogen bonds are observed in the molecule. The crystal studied was an inversion twin with a 0.513 (19):0.487 (19) domain ratio.


Experimental
The Vital Foundation of Ankang University (project No. 2008AKXY012), and the Special Scientific Research Foundation of the Education Office of Shanxi Province (Project No. 02JK202) are gratefully acknowledged.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB5004).

Comment
Study on the crystal structures of hydrazone derivatives is a hot topic in structural chemistry. In the last few years, the crystal structures of a large number of hydrazone compounds have been reported (Mohd Lair et al., 2009;Fun et al., 2008;Li & Ban, 2009;Zhu et al., 2009;Yang, 2007;You et al., 2008). As a continuation of our work in this area (Qu et al., 2008;Yang et al., 2008), the title new hydrazone compound, (I), derived from the reaction of 3,5-dibromo-2-hydroxybenzaldehyde with an equimolar quantity of 2-methoxybenzohydrazide is reported.

Experimental
The title compound was prepared by refluxing equimolar quantities of 3,5-dibromo-2-hydroxybenzaldehyde with 2-methoxybenzohydrazide in methanol. Colorless blocks of (I) were formed by slow evaporation of the solution in air.

Refinement
Atom H2 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 (C-H = 0.93-0.96 Å, O-H = 0.82 Å) and refined as riding with U iso (H) = 1.2U eq (C) or 1.5U eq (O and methyl C). The crystal studied was an inversion twin with a 0.513 (19):0.487 (19) domain ratio. Fig. 1. The molecular structure of (I) with ellipsoids drawn at the 30% probability level and hydrogen bonds indicated by dashed lines.

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 calculat-supplementary materials sup-3 ing 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.