(E)-4-Amino-N′-(5-chloro-2-hydroxybenzylidene)benzohydrazide

The title compound, C14H12ClN3O2, displays an E conformation with respect to the C=N double bond. The dihedral angle between the benzene rings is 41.3 (5)°. The molecular structure is stabilized by an intramolecular O—H⋯N hydrogen bond. In the crystal, N—H⋯O and weak N—H⋯Cl hydrogen bonds link the molecules into a three-dimensional architecture. In addition, there are weak C—H⋯π stacking interactions.

The title compound, C 14 H 12 ClN 3 O 2 , displays an E conformation with respect to the C N double bond. The dihedral angle between the benzene rings is 41.3 (5) . The molecular structure is stabilized by an intramolecular O-HÁ Á ÁN hydrogen bond. In the crystal, N-HÁ Á ÁO and weak N-HÁ Á ÁCl hydrogen bonds link the molecules into a threedimensional architecture. In addition, there are weak C-HÁ Á Á stacking interactions.
Data collection: SMART (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL. These complexes show interesting properties, e.g. their ability to reversibly bind oxygen, catalytic activity in hydrogenation of olefins and transfer of an amino group, photochromic properties, and complexing ability towards toxic metals (Karthikeyan et al., 2006;Khattab, 2005;Kucukguzel et al., 2006). Recently, hydrazone Schiff base compounds (Cao, 2009;Yang, 2009;Zhou & Yang, 2010;Zhang et al., 2009) derived from the reaction of aldehydes with hydrazines have been demonstrated to possess excellent biological activities, such as anti-bacterial, anti-convulsant, and antitubercular (Bernhardt & Caldwell et al., 2003;Bernhardt & Chin et al., 2005;Armstrong et al., 2003). In order to explore new anti-bacterial materials, a new hydrazone derivatives was prepared and characterized. It can be seen that in addition to the presence of the typical functional group -CO-NH-N═ CH-, the compound has chloro, hydroxy and amino substituents, which may enhance its biological properties.  Table 1), linking the molecules into a three-dimensional supramolecular structure. In addition, neighbouring molecules are also interact through weak C-H···π stacking interactions, Table 1.

Experimental
To a methanol solution (20 ml) of 5-chloro-2-hydroxybenzaldehyde (1 mmol, 0.157 g) and 4-aminobenzohydrazide (1 mmol, 0.151 g), a few drops of acetic acid were added. The mixture was refluxed for 2 h and then cooled to room temperature to give a yellow solution. Crystals of the title compound were formed by gradual evaporation of the solvent over a period of six days at room temperature.

Figure 1
The molecular structure of the title compound, with displacement ellipsoids at the 30% probability level.

Figure 2
Crystal packing in the title compound where molecules are linked via N-H···O and N-H···Cl hydrogen bonds (dashed lines). Except for those involved in hydrogen-bonding interactions, H atoms have been omitted for clarity. 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.