Phosphinate MOF formed from tetratopic ligands as proton conductive materials

Metal organic frameworks (MOFs) are attracting attention as potential proton conductors. There are two main advantages of MOFs in this application: the possibility of rational design and tuning of the properties, and clear conduction pathways given by their crystalline structure. We hereby present two new MOF structures, ICR-10 and ICR-11, based on tetratopic phosphinate ligands. The structures of both MOFs were determined by 3D electron diffraction. They both crystallize in the P-3 space group and contain arrays of parallel linear pores lined with hydrophilic non-coordinated phosphinate groups. This, together with the adsorbed water molecules, facilitates proton transfer via the Grotthuss mechanism, leading to the proton conductivity up to 4.26∙10-4 S cm-1 for ICR-11.