1,2-Bis[(1,3-benzodioxol-5-yl)methylidene]hydrazine

The complete molecule of the title compound, C16H12N2O4, is generated by the application of a centre of inversion. The (1,3-benzodioxol-5-yl)methylidene fused-ring system is approximately planar (r.m.s. deviation = 0.020 Å) and is essentially coplanar with the central hydrazine group [dihedral angle = 5.08 (9)°]. Weak π–π intermolecular interactions are observed [centroid–centroid distance = 3.8553 (8) Å], providing some packing stability.

ASP thanks the University of Mysore for research facilities. JPJ acknowledges the NSF-MRI program (grant No. CHE1039027) for funds to purchase the X-ray diffractometer.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: TK5026). as antimicrobial (El-Masry et al., 2000& Pandey et al., 1999, antifungal (Singh & Dash, 1988), antitumor (Hodnett & Dunn, 1970;Desai et al., 2001), and as herbicides. Schiff bases have also been employed as ligands for complexation of metal ions (Aydogan et al., 2001). On the industrial scale, they have a wide range of applications such as dyes and pigments (Taggi et al., 2002). Compounds containing an azine functionality or a diimine linkage have been investigated in terms of their crystallography and coordination chemistry (Xu et al., 1997;Kundu et al., 2005).

Experimental
A mixture of piperanal (3.0 g, 0.02 mol) and hydrazine hydrate (0.6 ml, 0.012 mol) was refluxed in 15 ml of absolute alcohol containing 2 drops of sulfuric acid, for about 3 hours. On cooling, the solid separated was filtered and dried. Single crystals were grown from DMF by slow evaporation. Yield: 81%. (M.pt.: 476 K).

Refinement
All of the H atoms were placed in their calculated positions and then refined using the riding model with C-H lengths of 0.93 Å (CH) or 0.97 Å (CH 2 ), and with U iso (H) set to 1.19-1.20 (CH, CH 2 ) × U eq (parent atom).

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 > σ(F 2 ) is used only for calculating Rfactors(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 )