First principle calculations of the adsorption of molecular H2 in Cu[Fe(CN)5NO] metal nitroprussides. An insight into H2–host interactions

The adsorption of H 2 inside a 2D-(two-dimensional) graphene-like model of the Cu[Fe(CN) 5 NO] nitroprusside and its anhydrous tetragonal phase has been analyzed using density functional theory. The H 2 –host interactions, geometries, and electronic properties have been studied from first principle calculations. Although the H 2 adsorption energies decrease with the amount of H 2 molecules, Natural Bond order analysis shows that the Kubas-type is the most stabilizing interaction. Weak vdW (van der Waals) forces between the hydrogen molecules (H 2 ⋯H 2 ) and the host structure were characterized with the Reduced Density Gradient function. An atom in molecules analysis shows other important molecular interactions such as CN⋯H (H 2 ) and NO⋯H (H 2 ). Excellent agreement between experimental and theoretical IR-spectra was obtained.