2-{[2-(2-Hydroxy-3-methoxybenzylidene)hydrazin-1-ylidene]methyl}-6-methoxyphenol

The title compound, C16H16N2O4, was obtained from the reaction of hydrazine hydrate and o-vanilin in absolute ethanol. The molecule is almost planar (except for the methyl H atoms), with a mean deviation from the plane of 0.0259 Å. The molecular structure also exhibits an approximate non-crystallographic twofold axis. Intramolecular O—H⋯N hydrogen bonds occur. In the crystal, intermolecular C—H⋯O hydrogen bonds generate molecular zigzag sheets. The sheets stack through C—H⋯π interactions, leading to a three-dimensional-network.

The title compound, C 16 H 16 N 2 O 4 , was obtained from the reaction of hydrazine hydrate and o-vanilin in absolute ethanol. The molecule is almost planar (except for the methyl H atoms), with a mean deviation from the plane of 0.0259 Å . The molecular structure also exhibits an approximate noncrystallographic twofold axis. Intramolecular O-HÁ Á ÁN hydrogen bonds occur. In the crystal, intermolecular C-HÁ Á ÁO hydrogen bonds generate molecular zigzag sheets. The sheets stack through C-HÁ Á Á interactions, leading to a three-dimensional-network.

Related literature
For the properties and applications of the title compound or similar structural compounds and their metal complexes, see: Lin et al. (2009); Davidson et al. (2006); Lin & Zeng (2006 Table 1 Hydrogen-bond geometry (Å , ).

Comment
The title compound, (I) (Fig. 1), with various chelating atoms, could coordinate with many transition metals (Davidson et al., 2006) and lanthanides (Lin and Zeng, 2006;Lin et al. , 2009) to form functional complexes. The molecule crystallizes in the monoclinic space group P21/c and appears to be almost completely planar (except for the methyl hydrogen atoms) with a mean deviation from the plane ooff 0.0259 Å. The molecule also exhibits a non-crystallographic 2-fold axis. There are intramolecular O-H···N hydrogen bonds, intermolecular C-H···O hydrogen bonds and C-H···π hydrogen bonds.
Molecules are linked by the C-H···O hydrogen bonds, generating molecular zigzag sheets, as shown in Fig. 2. The C-H···π hydrogen bonds and stacking interaction of these sheets leads to a three-dimensional-network. (Fig. 3).

Experimental
The title compound was obtained from the reaction of hydrazine hydrate and o-vanilin in absolute ethanol. Hydrazine hydrate (500 mg, 10 mmol) was added to a solution of o-vanilin (3.04 g, 20 mmol) in absolute ethanol (200 ml) and heated to reflux for 2 h. The resulting solution was allowed to evaporate at rt to give a yellow crystal, which was collected by filtration and dried under vacumn;; yield 89.3%. The single-crystal of the title compound suitble for X-ray diffraction was obtained by recrystalization from absolute ethanol.

Refinement
H atoms bonded to O atoms were refined isotropically without restraints, and with U iso (H) = 1.2U eq (O). Other H atoms were positioned geometrically and refined using a riding model with C-H = 0.95-0.99 Å and with U iso (H) = 1.2 (1.5 for methyl groups) times U eq (C). Fig. 1. The molecular structure of (I), with atom labels and 30% probability displacement ellipsoids for non-H atoms.