(665b) Computational Study of Small Molecules with the Open Metal Sites in Cu-BTC and CPO-Ni-27

The existence of open metal sites in metal organic frameworks (MOFs) plays an important role in the adsorption of molecules in these MOFs. We investigated the interaction of water, CO, and NO with the open metal sites in Cu-BTC and CPO-27-Ni using spatially periodic density functional theory. The magnetic state of the MOFs is found to make significant difference in the stability of the material. In Cu-BTC, two water molecules readily bind to a Cu dimer, as is known from experimental studies of the hydrated structure, but only one NO molecule can be adsorbed on a Cu dimer. We have also examined binding of larger molecules such as pyridine with the same methods and will discuss the potential for reversible binding of ligands of this type in MOFs as an avenue for manipulating the adsorption selectivity of MOFs for light gases in adsorption and membrane applications.