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

Che, G.-B., Liu, C.-B., Liu, B., Wang, Q.-W. & Xu, Z.-L. (2008). CrystEngComm, 10, 184–191. Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan. Rigaku (1998). PROCESS-AUTO. Rigaku Corporation, Tokyo, Japan. Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Steck, E. A. & Day, A. R. (1943). J. Am. Chem. Soc. 65, 452–456. Stephenson, M. D. & Hardie, M. J. (2006). Cryst. Growth Des. 6, 423–432. Xi, H.-M. (2008). Acta Cryst. E64, o1981. organic compounds

There are two molecules in the asymmetric unit of the title compound, C 19 H 12 N 4 , with dihedral angles of 2.41 (10) and 10.53 (12) between the fused ring system and the pendant phenyl ring. In the crystal, molecules are linked into chains by N-HÁ Á ÁN hydrogen bonds and aromaticstacking interactions [shortest centroid-centroid distance = 3.6176 (16) Å ] complete the structure.
The asymmetric unit of (I) consists of two independent L molecules ( Fig.1). The two phenyl rings are slightly twisted with respect to the fused-ring system [dihedral angles = 1.34 and 1.54 °], which is different from a related compound that has been reported (Xi, 2008). In the crystal structure, N-H···N hydrogen bonds (Table 1) link the molecules into chains along the b axis. The neighbouring chains interact through π-π contact between two L ligands [centroid separation = 3.541 Å], leading to the ultimate supramolecular structure (Fig. 2).

S2. Experimental
The L ligand was synthesized according to the literature method of Steck & Day (1943): a mixture of L, MnCl 2 and water in a molar ratio of 2:1:5000 was sealed in a Teflon-lined autoclave and heated to 413 K for 3 d. Upon cooling and opening the bomb, accidentally, pale yellow blocks of (I) were obtained.

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

Figure 2
A view of the crystal packing, showing the N-H···N hydrogen bonds and π-π stacking interactions. H atoms have been omitted.

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