1-(4-Methylphenyl)-2-[4-(trifluoromethyl)phenyl]-1H-phenanthro[9,10-d]imidazole

In the title compound, C29H19F3N2, the tetracyclic ring system is essentially planar [maximum deviation from the best plane = 0.076 (1) Å] and makes dihedral angles of 78.10 (5) and 33.71 (4)° with the methylphenyl and fluorophenyl rings, respectively. An intramolecular C—H⋯π interaction occurs. In the crystal, pairs of C—H⋯π interactions link inversion-related molecules.

In the title compound, C 29 H 19 F 3 N 2 , the tetracyclic ring system is essentially planar [maximum deviation from the best plane = 0.076 (1) Å ] and makes dihedral angles of 78.10 (5) and 33.71 (4) with the methylphenyl and fluorophenyl rings, respectively. An intramolecular C-HÁ Á Á interaction occurs. In the crystal, pairs of C-HÁ Á Á interactions link inversionrelated molecules.
The 1H-phenanthro[9,10 -d]imidazole is a promising building block in the field of molecular materials. It has many desirable properties such as good heat stability, ease of introduction into molecules used as chromophores, fluorescent in nature and readily tunable absorption wavelengths.
The study of organic electroluminescent materials and devices (Loy et al., 2002, Adachi et al., 1995 is therefore of great importance. The photophysical, electrochemical and mobility properties of phenanthroimidazole derivatives have been reported (Yuan et al., 2011).
As our research group deals with organic light emitting devices, we are interested in the title compound (I), Figure 1, as a ligand for inorganic complexes.
The dihedral angle between the phenanthrene moiety and the flourobenzene ring is 33.71 (4)° and to that of the benzene ring of methylphenyl is 78.10 (5)°. The dihedral angle between methylphenyl and benzene ring of trifluorobenzene ring is 72.60 (5)°. The maximum deviation of C12 atom from the mean plane of phenanthrotetracyclic system is 0.076 (1)°. The crystal structure is stabilized by C-H···π interactions. One of these, C12-H12···Cg1 is an intramolecular interaction. The other, C26-H26···Cg2 links the molecules into centrosymmetically related pairs across the centre-of-symmetry at (0.5, 0, 0.5), Figure 2. Cg1 and Cg2 are the centres of gravity of the benzene rings C15-C20 and C8-C13 respectively.

Refinement
All the hydrogen atoms were geometrically fixed and allowed to ride on their parent atoms with C-H = 0.93 -0.96 Å and U iso (H) = 1.3Ueq(C).
The methyl group attached to atom C28 was refined as 6 half hydrogen atoms since a diiference map did not reveal any distinct peaks.
A difference map in the plane of the F atoms of the CF 3 revealed 3 distinct peaks with evidence of oscillation around the C-C bond connecting the CF 3 group to the main molecule. The highest difference map peaks were located in the vicinity supplementary materials of the F atoms. Attempts were made to obtain a disordered model but none were satisfactory. These distinct maxima in the difference map were used as the starting positions of F atoms despite problem with thermal parameters during th refinement refinement.
The crystal was a non-merohedral twin. Refinement was carried out using BASF and HKLF 5. The twin data was obtained from PLATON TwinRotMat function, (Spek, 2009).
The twin component ratio is 0.961/0.039.

Figure 1
The molecular structure and labelling scheme for (I) with displacement ellipsoids for non-H atoms are drawn at the 30% probability level.   Dashed lines indicate C-H···π interactions. Hydrogen atoms not involved in the interactions are omitted for clarity. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.72 e Å −3 Δρ min = −0.38 e Å −3 Extinction correction: SHELXL97 (Sheldrick, 2008), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.022 (2) 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 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 Occ. (