4-Bromo-2-[(E)-(4-chlorophenyl)iminomethyl]phenol

In the title compound, C13H9BrClNO, the dihedral angle between the substituted benzene rings is 43.90 (11)°. Strong intramolecular O—H⋯N hydrogen bonds generate S(6) ring motifs. The crystal structure features short intemolecular Br⋯Br [3.554 (2) Å] and Cl⋯Cl [3.412 (2) Å] contacts. The crystal packing is further stabilized by intermolecular C—H⋯O and C—H⋯π interactions.


Comment
Schiff base ligands are one of the most prevalent systems in coordination chemistry. As part of a general study of Schiff bases, we have determined the crystal structure of the title compound.

Experimental
The title compound was synthesized by adding 5-bromo-salicylaldehyde (2 mmol) to a solution of p-chloroaniline (2 mmol) in ethanol (20 ml). The mixture was refluxed with stirring for half an hour. The resulting light-yellow solution was filtered.
Light-yellow single crystals suitable for X-ray diffraction were recrystallized from ethanol by slow evaporation of the solvents at room temperature over several days.

Refinement
H atoms of the hydroxy groups were located by a rotating model and constrained to refine with the parent atoms with U iso (H) = 1.5 U eq (O), see Table 1. The remaining H atoms were positioned geometrically with C-H = 0.93 Å and included in a riding model approximation with U iso (H) = 1.2 U eq (C).

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