Carbazole–anthraquinone conjugated microporous polymer photocatalysis for aerobic oxidative cyanation of tertiary amines irradiated by green light

Conjugated microporous polymers (CMPs), which can be designed through molecular building units, have been widely exploited as photoactive materials. Herein, carbazole and anthraquinone are utilized to prepare a carbazole–anthraquinone CMP (CzAQ-CMP) for visible light photocatalysis. Theoretical calculations suggest hole and electron are located at carbazole and anthraquinone, respectively. Besides, CzAQ-CMP allows for electron transfer to molecular oxygen via anthraquinone, forming superoxide. The hole of CzAQ-CMP drives aerobic oxidative cyanation of N,N-dimethylaniline in methanol. Intriguingly, in the presence of acetic acid, the nucleophilic substitution of trimethylsilyl cyanide by superoxide releases cyanide ion to partake in the α-cyanation of N,N-dimethylaniline. Irradiated by green light, the oxidative cyanation of diverse tertiary amines favorably affords the corresponding α-aminonitriles over CzAQ-CMP in high yields. This work illuminates the rational design of CMPs for photocatalytic selective organic transformations.