Three-dimensional covalent organic frameworks, due to their structured nanochannels, open pore environment and good stability, have gained more and more attention, and have shown good application prospects in the fields of gas storage and separation, catalysis, photoelectric sensing and drug transportation.
For the first time, we synthesized two new 3D COFs using icosahedral carborane with high stability as the building unit of 3D covalent organic frame materials, which enriches the types of 3D COFs. The crystal structure and porous properties of TAA-DFPB-COF and TAPM-DFPB-COF materials were confirmed by powder XRD, FT-IR, 11B NMR, 13C NMR, ICP-MS, TEM and BET. TGA and conventional solvent immersion experiments confirm that the COF material has excellent thermal and chemical stability.
TAA-DFPB-COF and TAPM-DFPB-COF have good stability and high specific surface area, and the interpenetrating microporous channels are rich in a large number of carborane structural units, which can efficiently separate hexane isomers through B−Hδ−•••Hδ+−C dihydrogen bond interaction. At the industrial separation temperature of hexane isomers, both materials showed good single-component adsorption performance for hexane isomers. Meanwhile, TAA-DFPB-COF showed excellent separation performance for hexane isomers based on thermodynamic separation mechanism and molecular sieve separation effect, and TAPM-DFPB-COF showed excellent separation effect for hexane isomers based on thermodynamic separation mechanism.