The recently designed CPO-27-M, where M=Mg,Mn,Fe,Co,Ni, and Zn represent a family of metal-organic framework compounds with the highest density of coordinatively unstaurated metal sites. Thermodynamically, the adsorption of hydrogen in these have been characterised in detail showing that the binding strenght increases with the increase of the atomic number of the constituent metal atom before dropping down in the case of Zn where the adsorption heat almost equals that for Mg. In the present application we propose to measure the INS spectra of H2 adsorbed in three selected structures in order to determine the adsorption sites potential strenght and shape for using these in PIMC model calculations employing both classical and DFT potential surfaces.