(Z)-3-(9-Anthryl)-2-(4-nitro-1H-imidazol-1-yl)-1-p-tolylprop-2-en-1-one

In the title molecule, C27H19N3O3, the imidazole and benzene rings make dihedral angles of 64.72 (4) and 64.02 (4)°, respectively, with the anthracene ring system (r.m.s. deviation = 0.043 Å). The nitro group is coplanar with the imidazole ring [dihedral angle = 1.1 (1)°]. The crystal packing is stabilized by weak π–π interactions with centroid–centroid distances of 3.7342 (10) and 3.7627 (9) Å.


Related literature
Chalcones or 1,3-diaryl-2-propen-1-ones are natural or synthetic compounds belonging to the flavonoid family (Vogel et al., 2008). They exhibit diverse kinds of biological activities. Hence, chalcones are considered as an important class of therapeutic agents. A series of chalcone derivatives containing a imidazole ring have been synthesized in our lab and crystal structues of some of them have been reported (Lu et al., 2009;Wang et al., 2009). We report here the crystal structure of the title compound.
In the molecular structure of the title compound ( Fig. 1), the imidazole and benzene ring of the tolyl group form dihedral angles of 64.72 (4)° and 64.02 (4)°, respectively, with the anthracene ring system (r.m.s. deviation 0.043 Å). The nitro group is coplanar with the imidazole ring [dihedral angle 1.1 (1)°].
The crystal structure is stabilized by weak π-π interactions between imidazole and benzene ring of the tolyl group (centroid to centroid distance = 3.7627 (9) Å) and those between the rings of the anthracene ring system (centroid to centroid distance = 3.7342 (10) Å).

S2. Experimental
The title compound was synthesized according to the procedure of Erhardt et al. (1985). Single crystals suitable for X-ray analysis was grown from a chloroform solution by slow evaporation at room temperature.

S3. Refinement
H atoms were placed at calculated positions with C-H = 0.93 Å (aromatic) and 0.96 Å (methyl). The U iso (H) values were set equal to 1.2U eq (C aromatic ) and 1.5U eq (C methyl ).  The molecular structure of the title compound, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

(Z)-3-(9-Anthryl)-2-(4-nitro-1H-imidazol-1-yl)-1-p-tolylprop-2-en-1-one
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.