2,4-Diiodo-6-[(propylimino)methyl]phenol

The title compound, C10H11I2NO, was prepared by the reaction of 3,5-diiodosalicylaldehyde with propylamine in ethanol. The molecule adopts an E conformation with respect to the C=N bond and the aromatic ring. The aromatic ring and the imino unit are close to being coplanar, with a dihedral angle of 2.6 (3)° between their planes. This planarity is assisted by the formation of an intramolecular O—H⋯O hydrogen bond.

The title compound, C 10 H 11 I 2 NO, was prepared by the reaction of 3,5-diiodosalicylaldehyde with propylamine in ethanol. The molecule adopts an E conformation with respect to the C N bond and the aromatic ring. The aromatic ring and the imino unit are close to being coplanar, with a dihedral angle of 2.6 (3) between their planes. This planarity is assisted by the formation of an intramolecular O-HÁ Á ÁO hydrogen bond.

Experimental
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SJ5194). Schiff bases have been extensively studied because of their biological activity (Chohan et al., 2012;Yan et al., 2011;Zhang et al., 2011). In addition, Schiff bases have been shown to be versatile ligands for the preparation of coordination complexes (You et al., 2008;Xu et al., 2009;Chen et al., 2010;Cui et al., 2011). In the present paper, the structure of the new title Schiff base compound is reported.
Experimental 3,5-Diiodosalicylaldehyde (0.37 g, 1 mmol) and propylamine (0.06 g, 1 mmol) were mixed in ethanol (20 ml). The mixture was stirred at room temperature for 30 min to give a yellow solution. Yellow block-shaped single crystals were obtained by slow evaporation of this solution in air.

Refinement
H1 was located from a difference Fourier map and refined isotropically, with the O-H distance restrained to 0.90 (1) Å.
The remaining H-atoms were positioned geometrically and refined using a riding model, with C-H = 0.93-0.97 Å, and with U iso (H) set to 1.2U eq (C) and 1.5U eq (C10).

2,4-Diiodo-6-[(propylimino)methyl]phenol
Crystal data Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > 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.