2-[(Z)-(3-{[(Z)-2-Hydroxy-3,5-diiodobenzylidene]amino}propylimino)methyl]-4,6-diiodophenol

In the title compound, C17H14I4N2O2, there are two intramolecular O—H⋯N hydrogen bonds, which make S(6) ring motifs. In the crystal, there are no significant intermolecular interactions present.

In the title compound, C 17 H 14 I 4 N 2 O 2 , there are two intramolecular O-HÁ Á ÁN hydrogen bonds, which make S(6) ring motifs. In the crystal, there are no significant intermolecular interactions present.

Related literature
For standard bond lengths, see: Allen et al. (1987). For hydrogen-bond motifs, see: Bernstein et al. (1995). For background to Schiff base ligands, see, for example: Kargar et al. Mo K radiation = 6.10 mm À1 T = 291 K 0.30 Â 0.14 Â 0.14 mm  Table 1 Hydrogen-bond geometry (Å , ).  In continuation of our work on the crystal structures of Schiff base ligands (Kargar et al., 2011;Kia et al., 2010), we synthesizes and carried out the X-ray structure analysis of the title compound.

Data collection
In the title compound, Fig. 1 (Bernstein et al., 1995). The bond lengths (Allen et al., 1987) and angles are within the normal ranges and are comparable to those reported for a similar structure (Kargar et al., 2012).
In the crystal, there are no significant intermolecular interactions present.

Experimental
The title compound was synthesized by adding 3,5-dibromosalicylaldehyde (2 mmol) to a solution of propylenediamine (1 mmol) in ethanol (30 ml). The mixture was refluxed with stirring for 30 min. The resultant solution was filtered. Lightyellow prismatic single crystals of the title compound, suitable for X-ray structure determination, were obtained by recrystallization from ethanol by slow evaporation of the solvents at room temperature over several days.

Refinement
The OH H atoms were located in a difference Fourier map and were constrained to ride on the parent O atom with U iso (H) = 1.5U eq (O). The C-bound H atoms were included in calculated positions and treated as riding atoms: C-H = 0.93 and 0.97 Å, with U iso (H) = 1.2U eq (C).  The molecular structure of the title compound, showing 40% probability displacement ellipsoids and the atomic numbering. 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.