N 2-(4-Chlorobenzylidene)-4-nitrobenzene-1,2-diamine

In the title compound, C13H10ClN3O2, the dihedral angle between the two benzene rings is 3.61 (6)°. In the crystal structure, molecules are linked by weak intermolecular C—H⋯O hydrogen bonds, forming layers parallel to the bc plane. Short intermolecular Cl⋯Cl contacts [3.491 (1) Å] are also observed.

In the title compound, C 13 H 10 ClN 3 O 2 , the dihedral angle between the two benzene rings is 3.61 (6) . In the crystal structure, molecules are linked by weak intermolecular C-HÁ Á ÁO hydrogen bonds, forming layers parallel to the bc plane. Short intermolecular ClÁ Á ÁCl contacts [3.491 (1) Å ] are also observed.
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 (Dao et al., 2000). Imine-type Schiff bases derived from aromatic amines and aromatic aldehydes are of growing interests because of their applications in many fields, including biological, inorganic, and analytical chemistry (Akbar Mobinikhaledi et al., 2009). In another application, So et al. (2007) synthesized and characterized a series of Schiff base derivatives, which exhibit liquid crystal properties. Some of these Schiff bases were found to form suitable inner coordination spheres bonding to tin atom with O and N atoms as quadridentate chelates (Teoh et al., 1997). Herein, we report the crystal structure of the title compound (I).

Experimental
The title compound was synthesized by adding 4-chlorobenzaldehyde (0.562 g, 4 mol) to the solution of 4-nitrobenzene-1,2-diamine (0.306 g, 2 mol) in methanol (30 ml). The mixture was refluxed for 3 h and left stirring overnight at room temperature. The resultant solid obtained was then filtered. Yellow needle-shaped single crystals suitable for X-ray structure determination were formed after slow evaporation of solvent at room temperature.

Refinement
The H atoms attached to N2 were located from a difference map and refined isotropically. The remaining H atoms were positioned geometrically and refined using a riding model [C-H = 0.93 Å , U iso (H) = 1.2U eq (C)].    (Cosier & Glazer, 1986) operating at 100.0 (1) K.
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.