Copper-promoted domino cyanation/Ullmann coupling toward difunctionalized acenaphthylenes with various optoelectronic properties

Tremendous progress has been made on aromatic fusion of acenaphthylene towards organic semiconductors. However, scarce studies focus on the functionalization of acenaphthylene without resort to aromatic extension, although vinylene double bond is highly reactive ascribed to the ring strain of the fused cyclopentene. Herein, for the first time we employ copper-promoted domino cyanation/Ullmann coupling to achieve a series of difunctionalized acenaphthylene imides (ANIs) with varied optoelectronic properties. Both Ullmann homocoupling and crosscoupling can be combined with cyanation for difunctionalization of ANIs. The introduction of cyano groups influences oppositely not only the energy levels but also the antiaromaticity of the five-membered rings in ANIs relative to the dimethylamino substituent due to the electron donating or withdrawing effects. By altering the functional units, the optical and electrical characteristics have been tailored rationally; thus p, n or ambipolar semiconducting properties can be achieved for the ANI derivatives. This article opens up possibilities to the development of organic semiconducting materials based on ANIs without aromatic extension, which is promising for applications in organic electronics.

Automated summary

In this study, a series of difunctionalized acenaphthylene imides (ANIs) with varied optoelectronic properties were successfully synthesized through copper-promoted domino cyanation/Ullmann coupling. The optical and electrical characteristics of the ANI compounds could be rationally tailored by altering the functional units, leading to the achievement of p, n or ambipolar semiconducting properties. This research opens up possibilities for the development of organic semiconducting materials based on ANIs without aromatic extension, showing promising applications in organic electronics.