(E)-4-Chloro-2-{[4-(dimethylamino)benzylidene]amino}phenol

In the title aromatic Schiff base compound, C15H15ClN2O, the molecule exists in a trans conformation with respect to the C=N bond. The dihedral angle between the benzene rings is 14.49 (6)°. In the crystal, weak C—H⋯π interactions link molecules into supramolecular chains propagated along the a-axis direction.

In the title aromatic Schiff base compound, C 15 H 15 ClN 2 O, the molecule exists in a trans conformation with respect to the C N bond. The dihedral angle between the benzene rings is 14.49 (6) . In the crystal, weak C-HÁ Á Á interactions link molecules into supramolecular chains propagated along the aaxis direction.

Comment
Schiff bases are widely used for synthetic purposes both by organic and inorganic chemists (Arora et al., 2002) and have uses as biological, analytical, polymer and liquid crystalline materials (Tanaka & Shiraishi, 2000). Schiff bases are reported to show a variety of biological activities such as antibacterial (Jarrahpour & Khalili, 2006;Jarrahpour et al., 2004;El-masry et al., 2000), antifungal (More et al., 2001;Singh & Dash, 1988), anticancer (Desai et al., 2001;Phatak et al., 2000) and herbicidal activities (Samadhiya & Halve, 2001). As an extension of our work on Schiff bases, we report here the crystal structure of the title compound (I).

Experimental
A mixture of 3,4-dimethoxyaniline (1 mmol) and 4-nitrobenzaldehyde (1 mmol) was added and heated to form a clear solution. To this a few drops of conc. H2SO4 was added as a catalyst and refluxed for 6 h. After cooling the solution, After stirring at 80°C for 20 min the formed precipitate was filtered off and washed with ice ethanol to give pure Schiff base as an yellow solid in an 80% yield. The crude product was dissolved in ethanol and two spoons of activated charcoal were added. The mixture was filtered over celite&reg; and the product was crystallized from ethyl acetate, yellow crystal was obtained after two weeks.

Refinement
Anisotropic thermal parameters were applied to all non hydrogen atoms. The organic hydrogen atoms attached to C atoms and N atom were fixed geometrically and treated as riding with C-H = 0.93 Å (aromatic) or 0.96 Å (methyl) and N-H = 0.86 Å with U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2U eq (C,N) for the others.  View of the molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level.

Data collection
Bruker APEXII CCD diffractometer Radiation source: sealed tube Graphite monochromator phi and ω scans 14319 measured reflections 2346 independent reflections 1895 reflections with I > 2σ(I) Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses 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 observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs 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.