N′-[(E)-2-Fluorobenzylidene]benzohydrazide

The asymmetric unit of the title compound, C14H11FN2O, contains two independent molecules, both of which adopt the E conformation with respect to the azomethine C=N bond. The molecules are non-planar, with dihedral angles of 26.92 (12) and 11.36 (11)° between the benzene and phenyl rings. In the crystal, molecules are linked through N—H⋯O=C and N—H⋯N hydrogen bonds into chains along [101]. C—H⋯O contacts link these chains into layers parallel to (001). The three-dimensional crystal packing is stabilized by π–π interactions, the shortest separation between the centroids of benzene rings being 3.884 (1) Å.

The asymmetric unit of the title compound, C 14 H 11 FN 2 O, contains two independent molecules, both of which adopt the E conformation with respect to the azomethine C N bond. The molecules are non-planar, with dihedral angles of 26.92 (12) and 11.36 (11) between the benzene and phenyl rings. In the crystal, molecules are linked through N-HÁ Á ÁO C and N-HÁ Á ÁN hydrogen bonds into chains along [101]. C-HÁ Á ÁO contacts link these chains into layers parallel to (001). The three-dimensional crystal packing is stabilized by interactions, the shortest separation between the centroids of benzene rings being 3.884 (1) Å . H atoms treated by a mixture of independent and constrained refinement Á max = 0.21 e Å À3 Á min = À0.17 e Å À3 Table 1 Hydrogen-bond geometry (Å , ).

Comment
The coordination chemistry of acyl and aroyl hydrazones have been a subject of competitive research as they are multipurpose class of ligands. Apart from exhibiting physiological and biological activities (Sreeja et al., 2004), they also function as catalysts (Heravi et al., 2007) as well as inhibitors for many enzymes (Tamasi et al., 2005).
The title compound crystallizes in monoclinic space group P2 1 /n. The asymmetric unit contains two molecules, both of which adopt the E configuration with respect to the C═N bond ( Fig. 1). They exist in the amido form with a C8═O1 bond length of 1.231 (2) Å and C22═O2 of 1.223 (2) Å, which are very close to the reported C═O bond length in closely related structure (Nair et al., 2012). Both molecules adopt the Z conformation with respect to the amido C-N bonds, with torsion angles of -7.2 (3)° and 5.5 (3)°.

Experimental
The title compound was prepared by adapting a reported procedure (Mangalam & Kurup, 2011). Benzoic acid hydrazide (1 mmol, 0.136 g) was dissolved in methanol and refluxed with methanolic solution of 2-fluorobenzaldehyde (1 mmol 0.124 g), in presence of a few drops of glacial acetic acid for 6 h. On cooling the reactant media, crystals of hydrazone were separated out. The crystals were filtered and washed with minimum quantity of methanol and dried over P 4 O 10 in vacuo. Good quality crystals suitable for X-ray analysis were obtained from methanolic solution by slow evaporation.

Refinement
All H atoms on C were placed in calculated positions, guided by difference maps, with C-H bond distances of 0.93 Å. H atoms were assigned U iso (H) values of 1.2Ueq(carrier). H atoms of N2-H2′ and N4-H4′ bonds were located from difference maps and the bond distances are restrained to 0.88±0.01 Å.   Hydrogen-bonding interactions of the title compound.  Packing diagram of the title compound along the a axis direction.