3-(1,2-Diphenylethenyl)-2-phenyl-1H-indole

In the title compound, C28H21N, the planar pyrrole ring makes dihedral angles of 1.5 (2), 42.4 (2), 65.4 (2) and 79.7 (1)°, with the least squares planes of the four phenyl rings. The molecular structure and crystal packing are stabilized by weak inter- and intramolecular C—H⋯π interactions.

In the title compound, C 28 H 21 N, the planar pyrrole ring makes dihedral angles of 1.5 (2), 42.4 (2), 65.4 (2) and 79.7 (1) , with the least squares planes of the four phenyl rings. The molecular structure and crystal packing are stabilized by weak inter-and intramolecular C-HÁ Á Á interactions.
MNM and PAM thank the Management of the New College (Autonomous), Chennai, India, for providing the necessary facilities.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: JJ2059).
3-(1,2-Diphenylethenyl)-2-phenyl-1H-indole P. A. A. Mahaboob, M. NizamMohideen, G. Bhaskar and P. T. Perumal Comment The indole ring system exists ubiquitously in natural products, and exhibits biological and pharmaceutical properties (Sundberg, 1996). Ferrer and co-workers reported a systematic investigation on the gold-catalyzed intra-and intermolecular addition of indoles to alkynes (Ferrer et al., 2007). Cheng and co-workers investigated the reaction of indoles with alkynyl alcohols employing platinum as a catalyst (Cheng et al., 2007). Development of heteroarene functionalization has attracted much attention of their wide range of applications such as fluorescent dyes, synthetic analogues of natural products, and pharmaceuticals (Ritleng et al., 2002). There has been considerable interest in the catalytic use of indium(III) halides in organic synthesis (Nair et al., 2004), due to their unique properties such as non-toxicity, stability in air, and water tolerance (Sakai et al., 2006). Indium(III) bromide is known to catalyze intramolecular cyclization of 2-alkynylanilines (Sakai et al., 2008). In continuation of our work in this area, the title compound, C 28 H 21 N, (I) has been prepared and its crystal structure is reported.

Experimental
A mixture of diphenylacetylene (2.4 mmol), 2-Phenyl indole (2 mmol), indium tribromide (0.2 mmol) in toluene (4 ml) was stirred at 383° K temperature for 2.5 h. After completion of the reaction as indicated by TLC, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were dried over anhydrous Na 2 SO 4 , concentrated in vacuo and purified by column chromatography on silica gel (Merck, 100 -200 mesh) to afford the desired product after crystallization.  Fig. 1. The molecular structure of the title compound with the atom numbering scheme and 50% probability displacement ellipsoids. H atoms are presented as a small spheres of arbitrary radius.