Self-coupling of electron acceptor units in conjugated microporous polymers strengthening local donor-acceptor interaction for improving photocatalytic activity.

The partial self-coupling of donor or acceptor unit during donor-acceptor (D-A) type CMPs synthesis is often overlooked for the effect on photocatalytic activity. Herein, we developed three D-A type CMPs, named SATE-CMP-n (n=1–3) , which were constructed from triazine (TEPT) unit (A) and three salen units (D). With the rigidity of salen units increasing (the rigidity: salen-1 < salen-2 < salen-3), the self-coupling proportion of TEPT decreases. The experiments and DFT calculations reveal that salen-1 has the stronger electron-donating ability compared to salen-2 and salen-3 , and that the self-coupling of TEPT units also enhances the electron-accepting ability. Therefore, SATE-CMP-1 exhibits the strongest D-A interaction and the highest separation and transfer efficiency of charge carriers, and has been used a photocatalyst for S−S and S−N coupling reactions. This work proves that the self-coupling of monomers in the construction of CMPs is not overlooked for adjusting the photocatalytic activity of catalyst. [Display omitted] • An effective method for detecting the proportion of monomer self-coupling in CMPs has been developed. • Three D-A type salen-based CMPs with different self-coupling proportion of acceptor unit were designed and synthesized. • In D-A type CMPs, partial self-coupling of acceptor units can improve photocatalytic efficiency. • The S-S and S-N coupling reactions can be efficiently catalyzed using D-A type salen-based CMPs as photocatalysts. [ABSTRACT FROM AUTHOR]