(E)-N′-(3-Fluorobenzylidene)-4-methylbenzohydrazide

In the title compound, C15H13FN2O, the dihedral angle between the benzene rings is 16.9 (2)°. The F atom and the O atom are in a syn conformation. In the crystal, molecules are linked by N—H⋯O hydrogen bonds to generate C(4) chains propagating along the b-axis direction.


D-HÁ
Data collection: SMART (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL. The molecular structure of the title compound is shown in Fig. 1. The two benzene ring system are inclined at a dihedral angle of 16.9 (2)°. All the bond lengths are comparable to those observed in related structures (Xu et al., 2009;Shafiq et al., 2009) and those we reported previously.
In the crystal structure, molecules are linked through N-H···O hydrogen bonds, to form one-dimensional chains running along the b axis ( Fig. 2 and Table 1).

Experimental
The title compound was prepared by the condensation reaction of 3-fluorobenzaldehyde (0.05 mol, 6.2 g) and 4-methylbenzohydrazide (0.05 mol, 7.5 g) in anhydrous methanol (100 ml) at ambient temperature. Colourless blocks were obtained by slow evaporation of the solution for several days.

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, and with U iso (H) = 1.2U eq (C) and 1.5U eq (C15).  The molecular structure of the title compound. Displacement ellipsoids are drawn at the 30% probability level.

Figure 2
The molecular packing of the title compound, viewed along the a axis. Hydrogen bonds are shown as dashed lines.
Hydrogen atoms not involved in hydrogen bonding have been omitted. 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.