A Symmetrically π‐Expanded Carbazole Incorporating Fluoranthene Moieties

A novel doubly cyclopentannulated carbazole which is accessible through a successive π‐expansion of di(1‐naphthylamine) is disclosed. The carbazole moiety is generated in the final step through intramolecular oxidative coupling. The π‐expansion of carbazole resulted in strongly altered optoelectronic and electrochemical properties. The solid‐state structure features an interesting packing motif with alternating face‐to‐face π⋅⋅⋅π and edge‐to‐face C−H⋅⋅⋅π interactions. The experimental findings were corroborated by theoretical calculations. Building big. A symmetrically π‐expanded carbazole incorporating fluoranthene moieties was assembled through a five‐step synthetic route. In comparison to parent N‐phenyl‐substituted carbazole the compound features significantly bathochromically shifted UV‐Vis absorption and emission maxima with considerably increased photoluminescence quantum yield. The π‐expansion results in facilitated oxidation with improved reversibility, while at the same time, the aromaticity of the central carbazole moiety remains unaffected.