(E)-5-Phenyl-N′-(1-phenylethylidene)-1H-pyrazole-3-carbohydrazide

In the molecule of the title compound, C18H16N4O, the intramolecular N—H⋯N hydrogen bond results in the formation of a planar five-membered ring, which is also co-planar with the adjacent five-membered ring, being oriented at a dihedral angle of 1.23 (3)°. The dihedral angles formed by the planar pyrazole ring with the adjacent phenyl ring and the other phenyl ring are 7.29 and 11.21°, respectively. The dihedral angle between the two phenyl rings is 18.07°. In the crystal structure, intermolecular N—H⋯O hydrogen bonds link the molecules.

In the molecule of the title compound, C 18 H 16 N 4 O, the intramolecular N-HÁ Á ÁN hydrogen bond results in the formation of a planar five-membered ring, which is also coplanar with the adjacent five-membered ring, being oriented at a dihedral angle of 1.23 (3) . The dihedral angles formed by the planar pyrazole ring with the adjacent phenyl ring and the other phenyl ring are 7.29 and 11.21 , respectively. The dihedral angle between the two phenyl rings is 18.07 . In the crystal structure, intermolecular N-HÁ Á ÁO hydrogen bonds link the molecules.   Table 1 Hydrogen-bond geometry (Å , ). Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: NRCVAX (Gabe et al., 1989); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL/PC (Siemens, 1990); software used to prepare material for publication: WinGX (Farrugia, 1999).

Related literature
(E)-5-Phenyl-N'-(1-phenylethylidene)-1H-pyrazole-3-carbohydrazide Y. Qin, F. Jian, H. Xiao and J. Zhang Comment Schiff bases have been used extensively as ligands in the field of coordination chemistry (Ogretir et al., 2006). As dinegatively charged ligands, Schiff bases show potential as antimicrobial and anticancer agents (Tarafder et al., 2000;Deschamps et al., 2003) and so have biochemical and pharmacological applications. In addition, the chemical behavior of metal complexes with Schiff base ligands has attracted much attention because of their catalytic activity in some industrial and biochemical processes (Wu et al., 2006). The title compound, (I), was synthesized as part of our study of these ligands and we report herein its crystal structure.
In the molecule of (I), ( In the crystal structure, intermolecular N-H···O hydrogen bonds (Table 1) link the molecules, in which they may be effective in the stabilization of the structure.

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