A static C NMR spectrum revealed a signal with a chemical shift consistent with physisorbed CO2 as expected, and with a lineshape consistent with an anisotropic chemical shift observed for the adsorbed CO2 (Figure ). While the lineshape is much narrower than that reported for solid CO2, the observed chemical shift anisotropy suggests that CO2 molecules have a preferred average orientation relative to the framework pores, consistent with other studies of similar frameworks. For the conditions studied in Figure , signal intensity at the left hand edge of the spectrum with a chemical shift d// could be assigned to CO2 adsorbed in crystals oriented parallel to the applied magnetic field, while signal intensity at the right hand edge could be assigned to CO2 adsorbed in crystals oriented perpendicular to the applied magnetic field d ⊥ . As was realised in earlier PFG NMR studies, the observation of a chemical shift anisotropy lineshape provides an excellent opportunity for the measurement of anisotropic diffusion. Indeed, as the gradient strength was increased in a series of PFG NMR experiments, clear lineshape changes are observed (Figure ), which arise from the anisotropic diffusion of CO2. In these experiments, the pulsed field gradient was applied along the laboratory z-axis, i.e. co-linear with the main applied magnetic field, B0. Therefore, the rapid decay of signal intensity at the left hand edge of the spectrum corresponds to the relatively fast self-diffusion along the length of the rod-like crystals, i.e. along the hexagonal pores of the metal-organic framework. On the other hand, the much slower decay of signal intensity at the right hand edge of the spectrum reports on the much slower diffusion of CO2 perpendicular to the MOF pores. Inspection of the spectra in Figure therefore confirms the anticipate result that D// >> D ⊥ . The above arguments were also substantiated by additional experiments in which the magnetic field gradients were instead applied along the laboratory x-axis.