Diffusion of long chain n-alkanes in the metal-organic framework MIL-47(V): A combination of neutron scattering experiments and molecular dynamics simulations

The self-diffusion of long chain n-alkanes in the metal-organic framework MIL-47(V) has been investigated by combining quasi-elastic neutron scattering (QENS) and molecular dynamics (MD) simulations. The experimental diffusivities, which are about one order of magnitude higher than in the zeolite silicalite, show a non-monotonous decrease with increasing chain length. Further, the activation energies for diffusion of C-9-C-16 are lower than in silicalite, indicating less conformational changes in this 1D-channel type MOF compared with the zeolite. MD simulations bring further insights into the microscopic diffusion mechanism in play confirming that diffusion proceeds via a jump sequence as suggested experimentally. (C) 2012 Elsevier Inc. All rights reserved.