Metal‐Organic Framework Nanoparticles with Universal Dispersibility through Crown Ether Surface Coordination for Phase‐Transfer Catalysis and Separation Membranes

Dispersing metal-organic framework (MOF) solids in stable colloids is crucial for their availability and processibility. Herein, we report a crown ether surface coordination approach for functionalizing the surface-exposed metal sites of MOF particles with amphiphilic carboxylated crown ether (CE^C ). The surface-bound crown ethers significantly improve MOF solvation without compromising the accessible voids. We demonstrate that CE^C -coated MOFs exhibit exceptional colloidal dispersibility and stability in 11 distinct solvents and six polymer matrices with a wide range of polarities. The MOF-CE^C can be instantaneously suspended in immiscible two-phase solvents as an effective phase-transfer catalyst and can form various uniform membranes with enhanced adsorption and separation performance, which highlights the effectiveness of crown ether coating.