2-{(E)-[(3-Iodo-4-methylphenyl)imino]methyl}-4-(trifluoromethoxy)phenol

The title compound, C15H11F3INO2, adopts the enol–imine tautomeric form. The molecule displays an E conformation with respect to the imine C=N double bond. The dihedral angle between the two benzene rings is 12.4 (2)°. The molecular conformation is stabilized by an intramolecular O—H⋯N hydrogen bond, which generates an S(6) ring motif. The trifluoromethoxyphenyl group is disordered over two sites with an occupancy ratio of 0.621 (6):0.379 (6). The crystal structure features C—H⋯π interactions.

The title compound, C 15 H 11 F 3 INO 2 , adopts the enol-imine tautomeric form. The molecule displays an E conformation with respect to the imine C N double bond. The dihedral angle between the two benzene rings is 12.4 (2) . The molecular conformation is stabilized by an intramolecular O-HÁ Á ÁN hydrogen bond, which generates an S(6) ring motif. The trifluoromethoxyphenyl group is disordered over two sites with an occupancy ratio of 0.621 (6):0.379 (6). The crystal structure features C-HÁ Á Á interactions.   Table 1 Hydrogen-bond geometry (Å , ).
Schiff base compounds display interesting photochromic and thermochromic properties in the solid state and can be classified in terms of these features (Cohen et al., 1964). Photo-and thermochromism arise via H-atom transfer from an hydroxy O atom to the imine N atom (Hadjoudis et al., 1987;Xu et al., 1994). Such proton-exchanging materials can be used for the design of various molecular electronic devices (Alarcon et al., 1999). In general, Schiff bases display two possible tautomeric forms, the phenol-imine (OH) and the keto-amine (NH) forms. Depending on the tautomers, two sort of intramolecular hydrogen bonds are observed in Schiff bases: O-H···N in phenol-imine (Gül et al., 2007) and N-H···O in keto-amine tautomers (Şahin et al., 2005).
As an extension of the work on the structural characterization of Schiff base compounds, the crystal structure of the title compound is reported here. Our researchs show that compound (I) adopts the phenol-imine tautomeric form. The molecular structure of the title compound is shown in Fig.1. The molecule contains two aromatic rings linked through a imine group. The dihedral angle between the two benzene ring is 12.4 (2)°. The C5-N1-C13-C7 torsion angle is 179.4 (3)°. The C13═N1 bond distance [1.272 (5) Å] is consistent with related structures (Aǧar et al., 2010;Tecer et al., 2010;Ceylan et al., 2011;Demirtaş et al., 2009).
The trifluoromethyl group is disordered and have been refined as such (see refinement details). The F atoms are disordered over two positions with refined site occupancies of 0.621 (6): 0.379 (6).

Refinement
The H1 atom was located in a difference map and refined subject to a DFIX (SHELXL97; Sheldrick, 2008) restraint of O -H=0.82 (2) Å. All other H atoms were placed in calculated positions and constrained to ride on their parents atoms, with C-H = 0.93-0.96 Å and U iso (H) = 1.2U eq (C) or 1.5U eq (C).

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.