(E,E)-2,5-Bis(5-chloro-2-methoxyphenyl)-3,4-diazahexa-2,4-diene

The title compound, C18H18Cl2N2O2, was synthesized by the reaction of 1-(5-chloro-2-methoxyphenyl)ethanone with hydrazine hydrate. The molecule lies on a crystallographic twofold axis passing through the mid-point of the N—N bond with one half-molecule in the asymmetric unit. The dihedral angle between the two aromatic rings is 44.33 (4)°. In the crystal, intermolecular C—H⋯O interactions link the molecules into columns along the c axis

The title compound, C 18 H 18 Cl 2 N 2 O 2 , was synthesized by the reaction of 1-(5-chloro-2-methoxyphenyl)ethanone with hydrazine hydrate. The molecule lies on a crystallographic twofold axis passing through the mid-point of the N-N bond with one half-molecule in the asymmetric unit. The dihedral angle between the two aromatic rings is 44.33 (4) . In the crystal, intermolecular C-HÁ Á ÁO interactions link the molecules into columns along the c axis
Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.  Recently, a number of azine compounds containing both a diimine linkage and N-N bonding have been investigated in terms of their crystallography and coordination chemistry (Kundu et al., 2005;Kesslen et al., 1999). As an extension of the work on the structural characterization of azine derivatives, the title compound, (I),was synthesized and its crystal structure is reported here.

Structure Reports Online
The molecule lies on a crystallogrpahic 2-fold axis passing through the mid-point of the N-N bond to give 1/2 molecule per asymmetric unit. (Fig. 1). The dihedral angle between the two aromatic rings is 44.33 (4)°. The N atom and the phenyl ring liie on opposite side of the C8=N1 bond to give an (E, E) conformation with respect to the C8=N1 bond ( and its symmetry related C8a=N1a double bond ( Fig. 1.). This configuration agrees with those commonly found in similar compounds (Glaser et al., 1995;Hunig et al., 2000). Intermolecular C-H···O interactions link the molecules into columns along the c axis (Table 1, Fig. 2).

Experimental
An ethanol solution (30 ml) of hydrazine (0.02 mol) and 1-(5-chloro-2-methoxyphenyl)ethanone (0.04 mol) was refluxed and stirred for 6 h; the mixture was cooled and the resulting solid product, (I), was collected by filtration. Colourless crystals suitable for single-crystal X-ray diffraction were grown by slow evaporation of a solution in acetone.

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