2-Phenyl-1H-1,3,7,8-tetraazacyclopenta[l]phenanthrene

There are two molecules in the asymmetric unit of the title compound, C19H12N4. One is almost planar [dihedral angle between the fused-ring system and the phenyl ring = 2.16 (13)°] and one is somewhat twisted [dihedral angle = 13.30 (14)°]. In the crystal, the molecules are linked by N—H⋯N hydrogen bonds to result in chains.


Related literature
The author thanks Beihua University for supporting this work.

S2. Experimental
1,10-Phenanthroline-5,6-dione (1.5 mmol) and benzaldehyde (1.5 mmol) were dissolved in CH 3 COOHCH 3 COONH 4 (1:1) solution (30 ml). The mixture was refluxed for 3 h under argon, after cooling, this mixture was diluted with water and neutralized with concentrated aqueous ammonia, immediately resulting a yellow precipitate, which was washed with water, acetone and diethyl ether respectively. Crystals of the title compound were obtained by recrystallization from dichloromethane.

S3. Refinement
C-and N-bound H atoms were positioned geometrically (N-H = 0.86 Å and C-H= 0.93 Å) and refined as riding, with U iso (H)= 1.2 U eq (carrier).  The structure of (I), showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

Data collection
Bruker APEX CCD area-detector diffractometer Radiation source: fine-focus sealed tube Graphite monochromator φ and ω scans Absorption correction: multi-scan (SAINT; Bruker, 1998) T min = 0.981, T max = 0.982 23942 measured reflections 5721 independent reflections 2627 reflections with I > 2σ(I) Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 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 C1