2-{[4-(Diethylamino)phenyl]iminomethyl}-4,6-diiodophenol

In the title compound, C17H18I2N2O, the dihedral angle between the aromatic rings is 5.4 (1)°. An intramolecular O—H⋯N hydrogen bond generates an S(6) ring motif. The crystal packing is stabilized by C—H⋯π and π–π interactions [centroid–centroid distance = 3.697 (1) Å].

Cg1 is the centroid of the C8-C13 ring. Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: XPREP (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 Schiff base compounds have received considerable attention for many years, primarily due to their importance in the development of coordination chemistry related to magnetism (Weber et al., 2007), catalysis (Chen et al., 2008) and biological processes (May et al., 2004). Against this background, and in order to obtain detailed information on molecular conformations in the solid state, an X-ray study of the title compound has been carried out.
The molecular structure is illustrated in Fig. 1. The geometric parameters of the title molecule agrees well with those reported for a similar structure (Manvizhi et al., 2010). The dihedral angle between the aromatic rings is 5.4 (1)°, showing that both the rings are almost coplanar.

Experimental
An ethanoic solution (30 ml) and N,N-diethyl aniline (10 mmol) was magnetically stirred in a round bottom flask followed by dropwise addition of 3,5-diiodosalicylaldehyde (10 mmol). The reaction mixture was then refluxed for two hours and upon cooling to 273K a yellow crystalline solid precipitated from the mixture. Single yellow crystals were obtained, filtered off, washed with ice cold ethanol and air dried.

Refinement
All the H atoms were positioned geometrically, with O-H = 0.82 Å and and C-H = 0.93 -0.98 Å and constrained to ride on their parent atom, with U iso (H)=1.2U eq . Fig. 1. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are presented as a small cycles of arbitrary radius.

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.