Crystal structure of (E)-2-[(2-hydroxy-4-methoxyphenyl)(phenyl)methylidene]-N-phenylhydrazine-1-carboxamide

The title compound, has an E conformation about the azomethine double bond and an intramolecular O—H⋯N hydrogen bond involving the phenolic hydrogen and the azomethine N atom. In the crystal, molecules are linked by bifurcated N—H⋯O hydrogen bonds involving the same acceptor atom, forming chains propagating along [001].


Chemical context
Semicarbazones are urea derivatives exhibiting a wide spectrum of biological activities (Beraldo & Gambino, 2004). They have been found to be associated with antitumoral (Afrasiabi et al., 2005), antimicrobial (Siji et al., 2010), antihypertensive, hypolipidemic, antineoplastic, hypnotic and anticonvulsant properties. They can function as excellent ligands to various metal ions (Kala et al., 2007;Aiswarya et al., 2013;Kurup et al., 2011) and can coordinate to metal ions either in the neutral (Siji et al., 2011) or in the anionic forms (Reena et al., 2008). Single crystals of acetophenone semicarbazones are potential organic non-linear optical (NLO) materials and they have a wide transparency window in the entire visible region, making them ideal candidates for NLO device applications (Vijayan et al., 2001). Semicarbazones have been proposed as analytical reagents that can be used in selective and sensitive determination of metal ions (Garg & Jain, 1988). The crystal structure of the dimethylformamide solvate of the title compound has been reported (Annie et al., 2012). ISSN 2056-9890

Structural commentary
In the molecule of the title compound ( Fig. 1), the conformation about the C7 N1 bond is E, and the central hydrazinecarboxamide moiety [-N1-N2-C14( O3)-N3-] is almost planar [the maximum deviation is 0.010 (2) Å for atom C14]. This central moiety is flanked by three aromatic rings (C1-C6, C8-C13 and C15-C20) which are inclined to its mean plane by 24.70 (10), 72.91 (12) and 34.26 (11) , respectively. Rings C1-C6 and C8-C13, attached at the same C atom (C7), are twisted away from each other and make a dihedral angle of 80.59 (12) . They are inclined to the phenylhydrazine ring (C15-C20) by 28.89 (11) and 52.42 (12) , respectively. In the crystal structure of the dimethylformamide solvate of the title compound (Annie et al., 2012), the two rings attached at the same C atom (C7) are inclined to one another by 88.47 (10) , while they are inclined to the phenylhydrazine ring by 14.42 (10) for the phenolic ring, and by 82.35 (11) for the phenyl ring. There is an intramolecular O-HÁ Á ÁN hydrogen bond ( Fig. 2) involving the phenolic hydrogen and the azomethine atom N1 ( Fig. 2 and Table 1). This hydrogen bond is also present in the structure of the dimethylformamide solvate of the title compound mentioned above.

Supramolecular features
In the crystal, the carbonyl O atom (O3) acts as the acceptor in bifurcated hydrogen bonds with the NH atoms of atoms N2 and N3 of the hydrazinic group, leading to the formation of chains propagating along [001]; Table 1  A view of the molecular structure of the title compound, with the atom labelling. Displacement ellipsoids are drawn at the 50% probability level. Table 1 Hydrogen-bond geometry (Å , ). Symmetry codes: (i) x; Ày þ 3 2 ; z À 1 2 ; (ii) x; y; z À 1.

Figure 2
A view of the hydrogen-bonding interactions (dashed lines) in the title compound, forming chains propagating along [001] (see Table 1 for details). There are also parallel slippedinteractions present (Fig. 4), involving inversion-related benzene rings (C15-C20) with a centroid-centroid distance of 3.8850 (14)

Synthesis and crystallization
To a warm methanolic solution (25 ml) of N 4 -phenylsemicarbazide (0.302 g, 2 mmol), a methanolic solution (25 ml) of 2-hydroxy-4-methoxybenzophenone (0.4566 g, 2 mmol) was added and the resulting solution was boiled under reflux for 2 h, after adding three drops of conc. HCl. On slow evaporation at room temperature, colourless crystals separated out. They were filtered off and washed with methanol and ether. Single crystals of the title compound suitable for X-ray analysis were obtained by slow evaporation of a solution in methanol (

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. The OH and NH H atoms were located in a difference Fourier map and refined with distances restraints of 0.88 (1) Å . The C-bound H atoms were placed in calculated positions and refined as riding atoms: C-H = 0.93-0.96 Å with U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2U eq (C) for other H atoms. interaction in the crystal structure of the title compound.

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.