(E)-2-(Benzyliminomethyl)-4,6-dibromophenol

The title compound, C14H11Br2NO, was prepared by the condensation of benzylamine and 3,5-dibromo-2-hydroxybenzaldehyde. The crystal structure is stabilized by aromatic π–π stacking interactions between the phenol rings of neighbouring molecules [centroid–centroid distance = 3.530 (5) Å]. In addition, the stacked molecules exhibit intermolecular C—H⋯π and intramolecular O—H⋯N interactions.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LX2061).

References
Bruker ( et al., 1964). The tautomerism involves proton transfer from the hydroxylic oxygen to the imino nitrogen atom that occurs intramolecularly via a six-membered ring, with the keto species showing bathochromically shifted spectra. As our continuing studies on the relation between the Schiff base geometry in the crystalline state and photochromism and/or thermochromism, here we report the crystal structure of the title compound, (E)-benzyliminomethyl-4,6-dibromophenol ( Fig. 1).
The molecular structure is a typical salicylaldehyde schiff derivative with normal geometric parameters. The molecular packing ( Fig. 2) is stabilized by π-π interactions between the phenol rings of neighbouring molecules. The Cg···Cg ii distance is 3.530 (5) Å (Cg1 is the centroid of the C9-C14 ring, symmetry code as in Fig. 2). The crystal packing (Fig. 2) is further stabilized by the C-H···π interactions between a methylene H atom of the benzyl group and the phenol ring, i.e.

Experimental
Benzylamine (0.02 mol, 2.14 g) and 3,5-dibromo-2-hydroxybenzaldehyde(0.02 mol, 5.498 g) were dissolved in ethanol and the solution was refluxed for 3 h. After evaporation, a crude product was recrystallized twice from ethanol to give a pure yellow product.  Fig. 1. The structure of (I), showing displacement ellipsoids drawn at the 30% probability level.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq