Computational study of propylene and propane binding in metal-organic frameworks containing highly exposed Cu⁺ or Ag⁺ cations

A synthetic route to create highly exposed, monovalent metal cations within the linkers of metal-organic frameworks (MOFs) is proposed and analyzed computationally. Quantum chemical calculations demonstrate the thermodynamic feasibility of incorporating Cu⁺ or Ag⁺ into a MOF containing an acetylene-bearing linker via postsynthesis modification. These highly exposed metal sites are predicted to bind propylene much more strongly than propane, suggesting their utility in adsorption separations. The nature of the propylene/metal binding is analyzed, and potential difficulties in activating the metal sites are discussed.