Solid-state NMR of small molecule adsorption in metal-organic frameworks (MOFs)

Metal-organic frameworks (MOFs) have gained significant attraction in the scientific community in the last two decades for their structural variety and because of that their multiple potential applications. These ordered, typically porous materials are well-suited for characterization with methods of solid-state NMR (SSNMR). The different elements involved in the MOF structure can be studied by multinuclear solid-state NMR. Furthermore, the porous structure allows for the adsorption of various small molecules. The characterization of orientation, adsorption sites, and dynamics of these small molecules in the porous MOF structure is perfectly suited for SSNMR methods ranging from relaxation time analysis, spectroscopy to diffusion studies. In this report, the focus is on adsorption studies in MOFs with solid-state NMR methods. After a general introduction to the field, typical aspects of certain MOFs and certain adsorbed molecules will be discussed. The combination with calculations and the different experimental approaches are also discussed.