MOP × MOF: Collaborative Combination of Metal-Organic Polyhedra and Metal-Organic Framework for Proton Conductivity.

We report a hybrid solid system, UMOM-100-a and UMOM-100-b, synthesized by incorporation of Cu-based metal-organic polyhedra (MOPs) into a porous metal-organic framework (MOF) host, PCN-777. The MOP guests have acid (SO3-) functional groups, acting as functionalized nanocages, whereas the porosity is still maintained for proton conductivity. The key parameter for the UMOM-100 series is the number of MOPs inside a MOF, which controls the ratio between meso- and micropores, polarity, and finally proton conductivity. This is an example demonstrating a new design strategy for porous solids to add active components into porous MOFs, opening up possibilities in other applications such as solid-state electrolytes and heterogeneous catalysts.