Unexpected diffusion anisotropy of carbon dioxide in the metal–organic framework Zn₂(dobpdc)

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Here, we investigate the diffusion of CO₂ within the pores of Zn₂(dobpdc) using pulsed field gradient nuclear magnetic resonance spectroscopy and molecular dynamics simulations. In addition to observing CO₂ diffusion through the channels parallel to the crystallographic c-axis, we unexpectedly find that CO₂ is also able to diffuse between the hexagonal channels in the crystallographic ab plane, despite the walls of these channels appearing impermeable in molecular dynamics simulations. This suggests the presence of defects that enable effective multidimensional CO₂ transport in a metal–organic framework with nominally one-dimensional porosity.

Recommended citation: Forse, Alexander C. et al. (2018). “Unexpected diffusion anisotropy of carbon dioxide in the metal–organic framework Zn₂(dobpdc).” J. Am. Chem. Soc. 140(5). 1663-1673.