Synthesis of Helical Indolophenanthridines Showing Aggregation-Induced Emission.

Helical indolo[2,3-]- and [3,2-]phenanthridines were synthesized from amines by amide formation and Morgan-Walls cyclization. The synthetic routes offer the advantage of late-stage derivatization and do not require protecting groups, which makes the compounds directly suitable for further functionalization. The compounds exhibit remarkable acid-dependent bathochromic shifts of the luminescence, solvatochromism, and aggregation-induced emission (AIE) behavior, which make them especially interesting candidates for studies toward optoelectronic applications.