2-Fluoro-N′-(2-hydroxybenzylidene)benzohydrazide

In the title compound, C14H11FN2O2, an intramolecular O—H⋯N hydrogen bond influences the molecular conformation; the two benzene rings form a dihedral angle of 18.4 (3)°. The F atom is disordered over two positions in a 0.717 (5):0.283 (5) ratio. In the crystal, intermolecular N—H⋯O hydrogen bonds link the molecules into chains extending along the c axis.

In the title compound, C 14 H 11 FN 2 O 2 , an intramolecular O-HÁ Á ÁN hydrogen bond influences the molecular conformation; the two benzene rings form a dihedral angle of 18.4 (3) . The F atom is disordered over two positions in a 0.717 (5):0.283 (5) ratio. In the crystal, intermolecular N-HÁ Á ÁO hydrogen bonds link the molecules into chains extending along the c axis.

Comment
As a contribution to a structural study of hydrazone compounds (Han & Zhao, 2010;Zhou & Yang, 2010;Huang & Wu, 2010;Shalash et al., 2010), we present here the crystal structure of the title compound.
There is an intramolecular O-H···N hydrogen bond (Table 1) in the molecule of the title compound (Fig. 1). The molecule exists in a trans configuration with respect to the methylidene unit. The molecule is twisted, with the dihedral angle between the two benzene rings of 18.4 (3)°. The torsion angle C7-N1-N2-C8 is 8.1 (3)°. The bond lengths are within normal ranges (Allen et al., 1987) and are comparable with those observed in the similar compounds (Xu et al., 2011).
In the crystal structure, molecules are linked through intermolecular N-H···O hydrogen bonds (Table 1) The mixture was stirred at room temperature to give a clear colorless solution. Colorless well shaped crystals of the title compound were formed by gradual evaporation of the solvent over a period of three days at room temperature.

Refinement
All H atoms were placed in geometrically idealized positions, with C-H = 0.93 Å, O-H = 0.82 Å, N-H = 0.86 Å, and refined as riding, with U iso (H) = 1.2U eq (C,N) and 1.5U eq (O). Atom F1 has been refined as disordered between two positions in a ratio 0.717 (5):0.283 (5) being attached either to C10 or C14, respectively. Fig. 1. The molecular structure of the title compound, with displacement ellipsoids drawn at the 30% probability level. The disordered fluorine atom F1 is shown in the major position. Dashed line denotes hydrogen bond. 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.

Figures
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )