Donor-acceptor type [4+3] covalent organic frameworks: sub-stoichiometric synthesis and photocatalytic application

Three unprecedented 2D [4+3] covalent organic frameworks (TTCOF-1, TTCOF-2, and TTCOF-3) have been prepared by sub-stoichiometric condensation of tetratopic and tritopic monomers, overcoming the limitations of the design rules of conventional topologies. By reticulating the tetraphenylethylene (TPE)-based and triazine-based moieties into COF frameworks, novel electron donor-acceptor (D-A) type structures were obtained. These TTCOFs have good photocatalytic activity in aerobic C(sp3)–H bond functionalization and arylboronic acid oxidation driven by visible light, with yields up to 94%. This can expedite possibilities of COFs with new structural and topological complexities and can also expand the application of COF-based photocatalysis in synthetic chemistry.