Equilibrium molecular dynamics simulations were performed to calculate self, corrected, and transport diffusivities of H-2 in the metal-organic frameworks NU-100 and UiO-68 with varying numbers of Mg alkoxide functionalizations per organic linker at 243 K. Preferred hydrogen siting locations, as well as H-2-H-2 radial distribution functions were calculated. Increasing functionalization leads to a decrease in the diffusivity values, especially at low hydrogen loadings. Although the functionalization effects on the mobility of hydrogen molecules are appreciable, diffusivity values are still large in all cases. (C) 2013 Elsevier B.V. All rights reserved.