N′-[(E)-1-Phenylethylidene]benzohydrazide

The title compound, C15H14N2O, crystallized with two independent molecules in the asymmetric unit. Both molecules are non-planar and have an E configuration with respect to the C=N bond. The dihedral angles between the two benzene rings are 11.1 (2)° in one molecule and 12.40 (19)° in the other. In the crystal structure, the molecules are linked by N—H⋯O hydrogen bonds and weak C—H⋯O interactions into infinite one-dimensional chains along [1 0 0]. The crystal structure is further stabilized by N—H⋯O hydrogen bonds, weak C—H⋯O and very weak C—H⋯π interactions.

The title compound, C 15 H 14 N 2 O, crystallized with two independent molecules in the asymmetric unit. Both molecules are non-planar and have an E configuration with respect to the C N bond. The dihedral angles between the two benzene rings are 11.1 (2) in one molecule and 12.40 (19) in the other. In the crystal structure, the molecules are linked by N-HÁ Á ÁO hydrogen bonds and weak C-HÁ Á ÁO interactions into infinite one-dimensional chains along [1 0 0]. The crystal structure is further stabilized by N-HÁ Á ÁO hydrogen bonds, weak C-HÁ Á ÁO and very weak C-HÁ Á Á interactions.
In the asymmetric unit of the title compound ( Fig. 1), there are two independent molecules A and B. Bond lengths in molecules A and B are slightly different but all are in normal ranges (Allen et al., 1987). Both molecules are not planar and exist in the E configuration which respect to the C═N bond. The dihedral angles between the two benzene rings are 11.1 (2)°i n A and 12.40 (19)° in B. In molecule A, the interplanar angle between the mean plane through N2A/O2A/C8A/C9A and N1A/N2A/C6A/C7A/C15A planes = 20.8 (2)°. In molecule B atoms N1B, N2B, C7B and C15B lie on the same plane and this plane makes the dihedral angle with the mean plane through N2B/O2B/C8B/C9B = 20.4 (2)°.  (Table 1); Cg 1 , Cg 2 , Cg 3 and Cg 4 are the centroids of the C1A-C6A, C1B-C6B, C9A-C14A and C9B-C14B rings, respectively.

Experimental
The title compound was obtained by refluxing phenyl hydrazide (0.01 mol) and acetophenone (0.01 mol) in ethanol (30 ml) by adding 3 drops of concentrated Sulfuric acid for 3 hr. Excess ethanol was removed from the reaction mixture under reduced pressure. The solid product obtained was filtered, washed with ethanol and dried. Colorless single crystals of the title compound suitable for x-ray structure determination were grown by slow evaporation of an ethanol solution at room temperature.

Refinement
All H atoms were constrained in a riding motion approximation with N-H = 0.73 and 0.91 Å, C aryl -H=0.93 and C methyl -H=0.96 Å. The U iso values were constrained to be 1.5U eq of the carrier atom for methyl H atoms and 1.2U eq for the remaining H atoms. A rotating group model was used for the methyl groups. The highest residual electron density sup-2 peak is located at 0.76 Å from C10A and the deepest hole is located at 0.72 Å from H1AA. As there is no large anomalous dispersion for the determination of the absolute structure, a total of 2250 Friedel pairs were merged before final refinement. Fig. 1. The asymmetric unit of (I), showing 50% probability displacement ellipsoids and the atomic numbering.

Special details
Experimental. The low-temperature data was collected with the Oxford Cyrosystem Cobra low-temperature attachment. 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 > σ(F 2 ) is used only for calculating Rfactors(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. supplementary materials sup-9