(E)-N′-(3-Fluorobenzylidene)-2-hydroxybenzohydrazide

The title compound, C14H11FN2O2, adopts an E or trans configuration with respect to the C=N bond. An intramolecular N—H⋯O hydrogen bond contributes to the relatively planarity of the molecular conformation; the two benzene rings are inclined to one another by 12.5 (2)°. In the crystal structure, intermolecular O—H⋯O hydrogen bonds link the molecules into chains running parallel to the c axis.

The title compound, C 14 H 11 FN 2 O 2 , adopts an E or trans configuration with respect to the C N bond. An intramolecular N-HÁ Á ÁO hydrogen bond contributes to the relatively planarity of the molecular conformation; the two benzene rings are inclined to one another by 12.5 (2) . In the crystal structure, intermolecular O-HÁ Á ÁO hydrogen bonds link the molecules into chains running parallel to the c axis.   Table 1 Hydrogen-bond geometry (Å , ). Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); 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.  (Kucukguzel et al., 2006;Khattab, 2005;Karthikeyan et al., 2006;Okabe et al., 1993). As part of an ongoing study of such compounds, we report here on the crystal structure of the title compound.

Related literature
The molecular structure of the title compound is shown in Fig. 1. It can be seen to display a trans configuration about the C=N bond. There is an intramolecular N-H···O hydrogen bond, involving the NH H-atom and the O-atom of the hydroxyl substituent (Table 1), and the dihedral angle between the two benzene rings is 12.5 (2)°.
In the crystal molecules are linked by intermolecular O-H···O hydrongen bonds to form chains running parallel to the c axis ( Fig. 2 and Table 1).

Experimental
Equimolar amounts of 2-Hydroxybenzohydrazide and 3-fluorobenzohydrazide were reacted in ethanol (10 ml) for 1 h. After allowing the resulting solution to stand in air for 10 days yellow block-shaped crystals were formed, on slow evaporation of the solvent.

Refinement
Phenyl ring C9-C14 was treated as a regular hexagon, and refined as a rigid body. The F-atom was found to be disordered over two positions, F1/F1', and given occupancies of 0.5/0.5. The H-atoms at C11 and C13 were also given occupancies of 0.5/0.5. All the H-atoms were placed in calculated positions and treated as riding: O-H = 0.82 Å, N-H = 0.86 Å, C-H = 0.93 Å, with U iso (H) = 1.5U eq (parent O and N-atom, and = 1.2U eq (parent C-atom).   Table 1).

Special details
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles 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.