(E)-4-Hydroxy-N′-(2-hydroxy-3,5-diiodobenzylidene)-3-methoxybenzohydrazide methanol monosolvate

In the title compound, C15H12I2N2O4·CH3OH, the hydrazone molecule exists in an E conformation with respect to the C=N bond. The dihedral angle between the rings is 11.9 (2)°. There is one intramolecular O—H⋯N hydrogen bond in the hydrazone molecule. In the crystal, the hydrazone and methanol molecules are linked through O—H⋯O and N—H⋯O hydrogen bonds and C—H⋯O interactions to form two-dimensional networks lying parallel to (001).


Xiao-Yan Li Comment
In recent years, hydrazone compounds have attracted much attention due to their syntheses and crystal structures (Hashemian et al., 2011;Lei, 2011;Shalash et al., 2010). As a continuation of our work on such compounds (Li, 2011a,b), the author reports herein on the crystal structure of the new title hydrazone compound.
In the crystal, the hydrazone and methanol molecules are linked through O-H···O and N-H···O hydrogen bonds and C-H···O interactions (Table 1), to form a two-dimensional network lieing parallel to the ab plane (Fig. 2).

Experimental
A mixture of 2-hydroxy-3,5-diiodobenzaldehyde (0.374 g, 1 mmol) and 4-hydroxy-3-methoxybenzohydrazide (0.182 g, 1 mmol) in 30 ml of ethanol containing few drops of acetic acid was refluxed for about 1 h. On cooling to room temperature, a solid precipitate was formed. The solid was filtered and then recrystallized from methanol. Colourless crystals, suitable for X-ray diffraction analysis, were obtained by slow evaporation of a solution of the title compound in methanol.

Refinement
Hydrogen atoms H2, H3, and H5 were located in a difference Fourier map and were freely refined. The remaining Hatoms were positioned geometrically and refined using a riding model: O-H = 0.82 Å, C-H = 0.93 and 0.96 Å for CH and CH 3 H atoms, respectively, with U iso (H) = k × U eq (O,C), where k = 1.5 for OH and CH 3 H-atoms, and k = 1.2 for all other H-atoms.   Table 1 for details).  Crystal packing of the title compound, viewed along the b axis. Hydrogen bonds are indicated by dashed lines (see Table   1 for details). The C-bound H-atoms have been omitted for clarity.

Special details
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles 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 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.