4,5-Diaza-9H-fluoren-9-imine

In the title compound, C11H7N3, the diazafluorene rings are almost coplanar with an r.m.s. deviation of 0.0160 Å. In the crystal structure, C—H⋯N hydrogen bonds link molecules into sheets parallel to the ab plane. Molecules are also stacked regularly along the c axis by a variety of π–π interactions with centroid–centroid distances in the range 3.527 (2)–3.908 (2) Å.

In the title compound, C 11 H 7 N 3 , the diazafluorene rings are almost coplanar with an r.m.s. deviation of 0.0160 Å . In the crystal structure, C-HÁ Á ÁN hydrogen bonds link molecules into sheets parallel to the ab plane. Molecules are also stacked regularly along the c axis by a variety ofinteractions with centroid-centroid distances in the range 3.527 (2)-3.908 (2) Å .
The molecular structure of (I) is shown in Fig. 1, and the selected geometric parameters are given in Table 1. The bond lengths and angles (Table 1) are within normal ranges (Allen et al., 1987). The diazafluorene rings are almost coplanar with an rms deviation 0.0160 Å.

Experimental
The title compound was synthesized by a method reported in literature (Wang & Rillema, 1997). Crystals were obtained by dissolving the compound (2.0 g, 11.0 mmol) in ethyl acetate(50 ml), and evaporating the solvent slowly at room temperature for about 5 d.

Refinement
H atoms were positioned geometrically, with N-H = 0.75 and C-H = 0.93Å for aromatic C-H, and constrained to ride on their parent atoms, with U iso (H) = xU eq (C/N), where x = 1.2 for aromatic H and x = 1.5 for the N-H. Fig. 1. A drawing of the title molecular structure, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

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.