Oriented PolyMOFs Enabled by Bridging Coligand for CO₂ Separation.

Abstract

Despite enormous research efforts in recent years, polymer-metal-organic framework (polyMOF) development still faces several drawbacks, such as the substantial decrease in surface area, poor crystallinity, and monophyletic chemical structure of polyMOFs. Herein, we overcome the constraints of the coordination mode of conventional polyMOFs and report a bridging coligand strategy to prepare new types of polyMOFs, where the MOFs featuring accessible Cu^II sites are compelled to orientally regrow within the confined channels of semirigid PIM-1 in dimethyl sulfoxide. Coordination-substitution characteristics and solvent-modulated synthesis enable the Cu centers in MOFs to coordinate with the N atoms from PIM-1 by bridging coligand mode. The reduced particle size, enhanced ultramicroporosity, preferential orientation, and superior filler-matrix compatibility endow the polyMOF-based mixed matrix membrane with excellent CO₂ separation performance, with a CO₂ permeability of 4669 Barrer, and with a CO₂/N₂ selectivity of ∼30. This polyMOF design concept exploits a viable avenue for developing more inorganic-organic hybrid materials.