4,6-Dichloro-2-{[(E)-(3-{[(E)-3,5-dichloro-2-hydroxybenzylidene]amino}-2,2-dimethylpropyl)imino]methyl}phenol

In the title compound, C19H18Cl4N2O2, a potential tetradentate Schiff base ligand, the dihedral angle between the two benzene rings is 48.01 (10)°. The configuration about the two C=N bonds is E and two intramolecular O—H⋯N hydrogen bonds make S(6) ring motifs. In the crystal, molecules are linked along the b axis via intermolecular C—H⋯Cl interactions. The crystal structure is further stabilized by an intermolecular π–π interaction [centroid–centroid distance = 3.5744 (12) Å].

In the title compound, C 19 H 18 Cl 4 N 2 O 2 , a potential tetradentate Schiff base ligand, the dihedral angle between the two benzene rings is 48.01 (10) . The configuration about the two C N bonds is E and two intramolecular O-HÁ Á ÁN hydrogen bonds make S(6) ring motifs. In the crystal, molecules are linked along the b axis via intermolecular C-HÁ Á ÁCl interactions. The crystal structure is further stabilized by an intermolecularinteraction [centroid-centroid distance = 3.5744 (12) Å ].

Comment
In continuation of our work on Schiff base ligands (Kargar et al., 2011;Kia et al., 2010), we present herein the crystal structure of the title compound.

Experimental
The title compound was synthesized by adding 3,5-dichloro-salicylaldehyde (2 mmol) to a solution of 2,2-dimethyl-1,3propanediamine (1 mmol) in ethanol (30 ml). The mixture was refluxed with stirring for 30 min. The resultant solution was filtered. Yellow single crystals of the title compound, suitable for X-ray analysis, were obtained by recrystallization from ethanol on slow evaporation of the solvent at room temperature over several days.

Refinement
The OH H-atoms were located in a difference Fourier map and were allowed to ride on the parent O-atom with U iso (H) = 1.5U eq (O). The C-bound H-atoms were included in calculated positions and treated as riding atoms: C-H = 0.93, 0.96 and 0.97 Å for CH, CH 3 and CH 2 H-atoms, respectively, with U iso (H) = k × U eq (C), where k = 1.5 for CH 3 H-atoms, and k = 1.2 for all other H-atoms. Fig. 1. A view of the molecular structure of the title compound, showing 40% probability displacement ellipsoids and the atomic numbering. The dashed lines indicate the intramolecular N-H···O hydrogen bonds (see Table 1 for details).

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