4-Bromo-2-[(phenylimino)methyl]phenol

The title compound, C13H10BrNO, is essentially planar (r.m.s. deviation = 0.026 Å) and the dihedral angle between the planes of the two aryl rings is 1.5 (3)°. An intramolecular O—H⋯N hydrogen bond generates an S(6) ring.


Synthesis and crystallization
4.0204g (20.0 mmol) 5-bromo-salicylaldehyde was dissolved in 30 mL of absolute ethanol. To it 1.822 mL (20.0 mmol) of aniline was added dropwise with a constant stirring. The reaction mixture was heated under refluxing for 3h. After cooling slowly, the light orange powder was separated out. The separated compound, (I), was filtered, washed thoroughly with absolute ethanol and dried in a vacuum desiccator with P 2 O 5 . Yield 91%. 0.2761g of (I) (1.0mmol) dissolved in 15 mL of absolute ethanol was heated under refluxing until thoroughly dissolved and 0.163 g (1.0 mmol) of VOSO 4 in 5 mL of water was added dropwise with a constant stirring. The reaction mixture was adjusted to pH = 7 with NaOH solution, and then it was heated under refluxing for 3h. After cooling slowly, the yellow-green precipitates were separated out.

Refinement
H atoms attached to C of (I) were placed in geometrically idealized positions with Csp 2 -H = 0.93Å. H atom attached to O of (I) was refined freely with the distance of O-H = 0.89 (6) Å.

Results and discussion
We report here the synthesis and characterization a potentially bidentate Schiff base derivative, (I), and prepared from the condensation reaction of an equimolar proportion of 5-bromo-salicylaldehyde and aniline in absolute ethanol. A Schiff base is condensed by primary amines and carbonyl compounds, containing strong electronegative with atoms O and N, so it is easily coordinated with metal ions to form stable complexes (Rehman et al., 2008). It is reported that metal complexes of schiff base derivatives have a variety of important biological activity,such as anti-bacterial, anti-cancer, anti-tumor, hypoglycemic and so on. (Vanco et al., 2008;Ritter et al., 2009).Our reports indicated that copper and vanadium complexes of Schiff bases are potential inhitors over protein tyrosine phosphatases. As part of the ongoing study of vanadium complexes inhibiting protein tyrosine phosphatases (Han et al., 2012), the aim of us is to synthesize new vanadium complex. Unfortunately, only the crystal structure of the title compound (I) was obtained.
The molecular structure and the crystal packing are depicted in Figure 1. X-ray structural analysis confirmed the title compound,(I), the dihedral angle between the two benzene rings is nearly 180° and and all non-H atoms are roughly coplanar with an r.m.s. deviation of 0.0255 Å for a mean plane fitted atomsin the model. There is a strong intramolecular O-H···N hydrogen bonds with a distance of 2.583 (6) Å between donor and acceptor, which generate S(6) ring.
The strong band in IR at 1614 cm -1 corresponds to the C7===N1, with a bond length of 1.283 (7)   A view of the structure of (I) with displacement ellipsoids drawn at the 50% probability level. Dot line indicates hydrogen bonding interaction. Δρ min = −0.33 e Å −3 Absolute structure: Flack (1983), 924 Friedel pairs Absolute structure parameter: 0.039 (18) 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.