Rationally modulating thiophene‐ and porphyrin‐based donor‐acceptor type covalent organic framework for effective photocatalytic organic reactions

Abstract

In order to specifically demonstrate the improvement of photocatalytic activity attributed to the donor‐acceptor (D‐A) structure rather than other contributing factors, two highly comparable COFs incorporating porphyrin and thiophene species are synthesized in this work. The first COF, named BTDA‐Por, is composed of porphyrin (Por) as the donor unit and 2,2′‐bithiophene (BTDA) as the acceptor moiety. The second COF, referred to as TT‐Por, is constructed using Por and thieno[3,2‐b]thiophene (TT) units while lacking a D‐A structure. These synthesized COFs serve as effective models for investigating the role of D‐A structures in improving photocatalytic activity. Photoelectronic property studies and density function theory calculations indicate that the D‐A configuration can significantly enhance the efficiency of charge carrier generation, separation, and migration. Consequently, the D‐A type BTDA‐Por exhibits superior performance in photochemical reactions such as oxidative homocoupling of aromatic amine and reversible complexation‐mediated radical polymerization when compared to the non‐D‐A type TT‐Por.