Three MOFs samples with high hydrogen storage capacities at 77K, and high surface area, are willing to be analyzed. In order to investigate hydrogen interactions within the porous framework host, we propose experiments to probe hydrogen dynamics in three MOFs samples, from which it should be possible to obtain information on the topology of their nanocavities, as well as on the guest-host interactions. TOSCA is the most suitable instrument due to its high resolving power in the energy range where the translational motion of hydrogen in the nanometric cages is expected to contribute to the inelastic spectra. We plan 3 runs per activated sample at 20K(thermal activation) including a blank run and 2 hydrogen loadings at 1bar and 9bar with respectively a cryostat at 20K and 30K and the sample at 77K while loading. Prior to the experiment should the thermal activation of each sample be done.