Covalent organic frameworks (COFs) are an emerging class of crystalline porous organic materials which are fabricated via reticular chemistry. Their topologic structures can be precisely predicted on the basis of the structures of building blocks. However, constructing COFs with complicated structures has remained a great challenge, due to the limited strategies that can access to the structural complexity of COFs. In this work, we have developed a new approach to produce COFs bearing three different kinds of pores. The design is fulfilled by the combination of vertex-truncation with multiple-linking-site strategy. On the basis of this design, a "V"-shaped building block carrying two aldehyde groups on the end of each branch has been synthesized. Condensation of it with 1,4-diaminobenzene or benzidine leads to the formation of two triple-pore COFs, TP-COF-DAB and TP-COF-BZ, respectively. The topological structures of the triple-pore COFs have been confirmed by PXRD studies, synchrotron small-angle X-ray scattering (SAXS) experiments, theoretical simulations, and pore size distribution analyses. Furthermore, for the first time, an in situ COF-to-COF transformation has also been achieved by heating TP-COF-BZ with 1,4-diaminobenzene under solvothermal condition, which leads to the formation of TP-COF-DAB via in situ replacing the benzidine linkers in TP-COF-BZ with 1,4-diaminobenzene linkers.

Few layer COFs was incorporated with rGO to provide composite cathode materials with improved energy storage capability.

We herein report the construction of a new heteropore COF which consists of two different kinds of micropores with unprecedented shapes. It exists as hollow microspheres and exhibits an extremely high volatile iodine uptake (up to 481 wt%) by encapsulating iodine in the inner cavities and porous shells of the microspheres.