Docking of CuI and AgI in Metal–Organic Frameworks for Adsorption and Separation of Xenon

We present a metal docking strategy utilizing the precise spatial arrangement of organic struts as metal chelating sites in a MOF. Pairs of uncoordinated N atoms on adjacent pyrazole dicarboxylate linkers distributed along the rod-shaped Al–O secondary building units in MOF-303 [Al(OH)(C5H2O4N2)] were used to chelate CuI and AgI with atomic precision and yield the metalated Cu- and Ag-MOF-303 compounds [(CuCl)0.50Al(OH)(C5H2O4N2) and (AgNO3)0.49Al(OH)(C5H2O4N2)]. The coordination geometries of CuI and AgI were examined using 3D electron diffraction and extended X-ray absorption fine structure spectroscopy techniques. The resulting metalated MOFs showed pore sizes matching the size of Xe, thus allowing for binding of Xe from Xe/Kr mixtures with high capacity and selectivity. In particular, Ag-MOF-303 exhibited Xe uptake of 59 cm3 cm−3 at 298 K and 0.2 bar with a selectivity of 10.4, placing it among the highest performing MOFs.