The 2025 Nobel prize in Chemistry and the ILL

MOFs are porous materials that are made up of metal atoms linked by organic (carbon-based) molecules called ligands. Together, the metal ions and the ligands form crystals with large cavities, in which molecules can flow in and out.

MOFs are about how molecules can be built together into structures – the Nobel committee called it "molecular architecture" – and this turns out to be an extremely rich playground for chemists and materials scientists, in, which chemical and phsical properties, and function, can be finely tuned – currently about 100 000 MOFs have been reported and half a million are predicted to exist.

By varying the building blocks used in the MOFs, chemists can design them to capture and store specific substances. Researchers have used them to harvest water from desert air, extract pollutants from water, capture carbon dioxide and store hydrogen.

MOFs can have inner surface areas of several thousand square metres per gramme! This is a measure of their capacity to adsorb or store small molecules, for example H2 for energy applications and CO2 for sequestration. The pores can be tuned in size, which also makes them very useful for molecular sieving applications.

Neutron scattering is an invaluable tool for studying materials and processes occurring at different time and length scales. Neutrons are ideal probes of MOFs since they ‘see’ the metals and organic molecules equally well. Many scientists at ILL are involved in research concerning a variety of MOFs for a wide range of applications. Neutron techniques like diffraction and quasielastic and inelastic neutron scattering enable structures to be determined precisely, including the adsorption sites of guest molecules like H₂ and CO₂, as well as the dynamics of the framework and encaged molecules.

Worth mentioning in this context is the work of ILL scientists with the now Nobel laureate Susumu Kitagawa and his colleagues on a spin crossover MOF in which the magnetic (spin) state of the iron centre can act as a switch for the rotation dynamics of a ring-shaped molecule (ref 7). 

MOFs have been, are and will continue to be an important area of activity at ILL - we estimate that several hundred experiments have been performed on MOFs at ILL, leading to about one hundred publications, and there are currently three PhD projects running at ILL.