(E)-N′-(5-Bromo-2-hydroxybenzylidene)-3-methylbenzohydrazide

In the title molecule, C15H13BrN2O2, an intramolecular O—H⋯N hydrogen bond influences the molecular conformation; the two benzene rings form a dihedral angle of 13.6 (3)°. In the crystal, intermolecular N—H⋯O hydrogen bonds link the molecules into chains along the a axis and weak intermolecular C—H⋯O hydrogen bonds further link these chains into layers parallel to the ac plane.

In the title molecule, C 15 H 13 BrN 2 O 2 , an intramolecular O-HÁ Á ÁN hydrogen bond influences the molecular conformation; the two benzene rings form a dihedral angle of 13.6 (3) . In the crystal, intermolecular N-HÁ Á ÁO hydrogen bonds link the molecules into chains along the a axis and weak intermolecular C-HÁ Á ÁO hydrogen bonds further link these chains into layers parallel to the ac plane.

Comment
Considerable attention has been focused on hydrazones and their medicinal applications (Hillmer et al., 2010;Raj et al., 2007). The crystal structures of such compounds are of particular interest (Vijayakumar et al., 2009). As a continuation of our work with hydrazone compounds (Liu & You, 2010;Liu & Wang, 2010), we report herein the crystal structure of the title compound, (I).
In the crystal structure, molecules are linked through N-H···O hydrogen bonds (Table 1), to form one-dimensional chains running along the a axis (Fig. 2). Weak intermolecular C-H···O hydrogen bonds (Table 1) link further these chains into layers parallel to ac plane.

Experimental
The title compound was prepared by the condensation reaction of 5-bromosalicylaldehyde (0.05 mol, 10.0 g) and 3-methylbenzohydrazide (0.05 mol, 7.5 g) in anhydrous methanol (100 ml) at ambient temperature. Colourless block-shaped single crystals suitable for X-ray structural determination were obtained by slow evaporation of the solution for 5 d.

Refinement
H2 was located from a difference Fourier map and refined isotropically, with the N-H distance restrained to 0.90 (1) Å.
The remaining H atoms were positioned geometrically and constrained to ride on their parent atoms, with C-H distances of 0.93-0.96 Å, O-H distance of 0.82 Å, and with U iso (H) = 1.2U eq (C) and 1.5U eq (O1 and C15). Fig. 1. The molecular structure of (I). Displacement ellipsoids are drawn at the 30% probability level. Hydrogen atoms are shown as spheres of arbitrary radius and the intramolecular hydrogen bond is drawn as a dashed line. 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.