Cooperative C–H…N and C–H…π bonded molecular dimers of 5-aryl-7,8,13,14-tetrahydro-dibenzo[a,i]phenanthridine

As a result of our new high-yielding one-pot reaction procedure, the investigation on a series of heterocyclic 5-aryl-7,8,13,14-tetrahydro-dibenzo[a,i]phenanthridine compounds was possible and reported: 5-(4-ethyl-phenyl)-7,8,13,14-tetrahydro-dibenzo[a,i]phenanthridine, 5-(4-cyano-phenyl)-7,8,13,14-tetrahydro-dibenzo[a,i]phenanthridine, and 5-(2-ethyl-phenyl)-7,8,13,14-tetrahydro-dibenzo[a,i]phenanthridine. Half-chair conformation of alicyclic rings gives rise to a slightly folded structure of central tricyclic phenanthridine. The structure analysis showed the formation of a well-defined dimeric unit in the crystals. Dimeric association essentially involves cooperative C–H…N and C–H…π close contacts between molecules related by a center of inversion. The first two compounds are isomorphous with noticeable differences in steric packing. The first structural elucidation on 5-aryl-7,8,13,14-tetrahydro-dibenzo[a,i]phenanthridine compounds indicates the prominent mode of interactions, which has use in structure-based drug discovery and optoelectronic applications.