Three-Dimensional Covalent Organic Framework with ceq Topology

Three-dimensional covalent organic frameworks (3D-COFs) are emerging as designable porous materials because of their unique structural characteristics and porous features. However, because of the lack of 3D organic building units and the less reversible covalent bonds, the topologies of 3D-COFs to date have been limited to dia, ctn, ffc, bor, rra, srs, pts, lon, stp, acs, tbo, bcu, and fjh. Here we report a 3D-COF with the ceq topology utilizing a D_3h-symmetric triangular prism vertex with a planar triangular linker. The as-synthesized COF displays a twofold-interpenetrated structure with a Brunauer-Emmett-Teller surface area of 1148.6 m² g^-1. Gas sorption measurements revealed that 3D-ceq-COF could efficiently absorb CO₂, CH₄, and H₂ under a moderate surface area. This work provides new building units and approaches for structural and application exploration of 3D-COFs.