(2E)-N′-[(E)-2-Hydroxybenzylidene]-3-phenylprop-2-enohydrazide

In the non-planar title compound, C16H14N2O2, the dihedral angle between the phenyl rings is 16.67 (8)°. An E conformation is found for each of the imine [1.286 (2) Å] and ethylene [1.335 (2) Å] bonds. The amide O and H atoms are anti, and an intramolecular hydroxy O—H⋯N hydrogen bond is noted. The formation of N—H⋯O(hydroxy) hydrogen bonds in the crystal packing leads to helical chains along the b axis. Supramolecular layers in the ab plane are formed as the chains are linked by C—H⋯O interactions.

In the non-planar title compound, C 16 H 14 N 2 O 2 , the dihedral angle between the phenyl rings is 16.67 (8) . An E conformation is found for each of the imine [1.286 (2) Å ] and ethylene [1.335 (2) Å ] bonds. The amide O and H atoms are anti, and an intramolecular hydroxy O-HÁ Á ÁN hydrogen bond is noted. The formation of N-HÁ Á ÁO(hydroxy) hydrogen bonds in the crystal packing leads to helical chains along the b axis. Supramolecular layers in the ab plane are formed as the chains are linked by C-HÁ Á ÁO interactions.
The use of the EPSRC X-ray crystallographic service at the University of Southampton, England, and the valuable assistance of the staff there is gratefully acknowledged. JLW acknowledges support from CAPES (Brazil). Structural studies are supported by the Ministry of Higher Education (Malaysia) through the High-Impact Research scheme (UM.C/HIR/MOHE/SC/3).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB6860).  (Carvalho et al., 2012a). For example, (I), exhibits considerable trypanocidal activity (Carvalho et al., 2012b). Herein, the crystal structure determination of (I) is described.
In (I), Fig. 1, there is a twist in the molecule as seen in the dihedral angle between the phenyl rings of 16.67 (8) Table 1; the layers inter-digitate along the c axis, Fig. 4.

Experimental
The title compound was prepared as reported (Carvalho et al., 2012b). The sample used in the crystallographic study was grown from its EtOH solution and intensity data was collected at the National Crystallographic Service, England (Coles & Gale, 2012).

Refinement
The C-bound H atoms were geometrically placed (C-H = 0.95 Å) and refined as riding with U iso (H) = 1.2U eq (C). The Oand N-bound H atoms were located from a difference map and refined with the distance restraint O-H = 0.84±0.01 and N-H = 0.88±0.01 Å, and with U iso (H) = zU eq (carrier atom); z = 1.5 for O and z = 1.2 for N. In the absence of significant anomalous scattering effects, 1033 Friedel pairs were averaged in the final refinement. One reflection, i.e. (20 0 0) was omitted from the final refinement owing to poor agreement.

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s 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 > 2σ(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.