Isoreticular 3D covalent organic frameworks with non-interpenetrated pcu-derived dia topology: pore regulation from micropores to mesopores

Abstract

Three-dimensional (3D) covalent organic frameworks (COFs) offer tremendous potential for a range of applications due to their unique structural and porous features. However, achieving the reticular synthesis of 3D COFs with regulated pores through isoreticular expansion remains a significant challenge, primarily due to the occurrence of interpenetration. In this study, we present a novel strategy that utilizes high-coordinated building blocks, acting as a binodal group of tetrahedral nodes, to synthesize isoreticular 3D COFs (JUC-300 to -302) with tunable pore sizes and uncommon non-interpenetrated pcu-derived dia topology. The pore sizes of these COFs were successfully tuned from 1.6 to 5.2 nm. The mesopores with a size of 5.2 nm in JUC-302 are the largest reported among 3D COFs to date and demonstrated the effective incorporation of a large protein, myoglobin. The strategy provides a new pathway for synthesizing isoreticular 3D COFs with reduced interpenetration, enabling applications that depend on various pore sizes.