(E)-N′-(2-Hydroxy-3,5-diiodobenzylidene)-3-methylbenzohydrazide

In the title compound, C15H12I2N2O2, the dihedral angle between the benzene rings is 26.5 (3)° and the molecule has an E configuration about the C=N bond. An intramolecular O—H⋯N hydrogen bond is observed in the molecule. In the crystal, molecules are linked by N—H⋯O hydrogen bonds, forming chains along the c axis.


Related literature
Hydrogen-bond geometry (Å , ). Financial support from the Jiaying University research fund is gratefully acknowledged.

Comment
Hydrazone compounds have received much attention in biological and structural chemistry in the last few years (Rasras et al., 2010;Pyta et al., 2010;Angelusiu et al., 2010;Fun et al., 2008;Singh & Singh, 2010;Ahmad et al., 2010). As a continuation of our work on the structural study on such compounds (Tang, 2010(Tang, , 2011, the author reports herein the crystal structure of the new title hydrazone compound. In the title compound ( Fig. 1), the dihedral angle between the two benzene rings is 26.5 (3)°. An intramolecular O1-H1···N1 hydrogen bond (Table 1) is observed in the molecule, which has an E configuration about the N1═C7 bond.
Bond lengths in the compound are normal (Allen et al., 1987) and comparable to those in the similar compounds mentioned above. In the crystal, molecules are linked through intermolecular N-H···O hydrogen bonds, forming chains along the c axis ( Fig. 2 and Table 1).
Experimental 2-Hydroxy-3,5-diiodobenzaldehyde (0.1 mmol, 37.5 mg) and 3-methylbenzohydrazide (0.1 mmol, 15.0 mg) were dissolved in methanol (20 ml). The mixture was stirred at reflux for 10 min to give a clear colourless solution. Colourless needle-shaped crystals of the compound were formed by slow evaporation of the solvent over several days.

Refinement
The amino H atom was located in a difference Fourier map and refined isotropically, with the N-H distance restrained to 0.90 (1)   The molecular structure of the title compound, showing the atom-numbering and displacement ellipsoids drawn at the 30% probability level. The intramolecular O-H···N hydrogen bond is shown as a dashed line (see Table 1 for details).

Figure 2
Crystal packing of the title compound, viewed along the a axis. Hydrogen bonds are shown as dashed lines (see Table 1 for details). 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.