Crystal structure of 9-butyl-3-(9-butyl-9H-carbazol-3-yl)-9H-carbazole

In the title carbazole derivative, C32H32N2, the molecule resides on a crystallographic twofold axis, which runs through the central C—C bond. The carbazole ring system is almost planar, with a maximum deviation of 0.041 (1) Å for one of the ring-junction C atoms. The crystal packing is stabilized by C—H⋯π interactions only, which form a C(7) chain-like arrangement along [110] in the unit cell.

Cg is the centroid of the C7-C12 ring.

S1. Comment
Carbazole based materials play vital roles in various areas of research. Various carbazole based heterocycles exhibit a diverse range of biological activities including pim kinase inhibitory (Giraud et al., 2014), anti-inflammatory, antioxidant (Bandgar et al., 2012), antimicrobial (Gu et al., 2014), antitumor (Wang et al., 2011), and anti-Alzheimer (Thiratmatrakul et al., 2014) activities etc. On the other hand, this class of materials has been identified as potential ones for OLED applications (Shi et al., 2012.;Tavasli et al., 2012;Kim et al., 2011;Zhuang et al., 2012). As an intermediate for the development of new carbazole based materials for biological/OLED applications, a dibutylbicarbazole has been synthesized and single crystals were grown by slow evaporation in ethanol.
The X-ray study confirmed the molecular structure and atomic connectivity of the title compound, as illustrated in The carbazole ring system is planar with a maximum deviation of -0.041 (1) Å for atom C7. The atom C13 attached to the carbazole ring system deviates by 0.250 (1) Å from the best plane of the carbazole ring system.

S2. Experimental
In a round-bottomed flask (250 ml), iron(III) chloride (44.80 mmol) in chloroform (100 ml) was taken under nitrogen atmosphere. Then, 9-butyl-9H-carbazole (11.20 mmol) (Ramalingan et al., 2010) in chloroform (50 ml) was added in a drop-wise fashion and was stirred at ambient temperature for 1 hour. After the addition of a sodium hydroxide solution (10%), the organic phase was separated and the aqueous phase was extracted with chloroform. The combined organic phases were dried and concentrated to obtain the crude product which was dissolved in chloroform (15 ml) and reprecipitated slowly using methanol (200 ml). The product, thus, obtained was filtered, dried under vacuum at ambient temperature. Single crystals of (I) were obtained by slow evaporation of ethanol solution of the title compound at room temperature.

S3. Refinement
H atoms were placed in idealized positions and allowed to ride on their parent atoms, with C-H distances of 0.93-0.97 Å, and U iso (H) = 1.5U eq (methyl C) and U iso (H) = 1.2U eq for other C atoms. The molecular structure of the title compound, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

Figure 2
Molecular packing of the title compound, viewed along the a axis; C-H···π interactions are shown as dashed lines.For the sake of clarity, H atoms, not involved in hydrogen bonds, have been omitted for clarity. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.24 e Å −3 Δρ min = −0.19 e Å −3 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.