Pore Shape Modification of a Microporous Metal–Organic Framework Using High Pressure: Accessing a New Phase with Oversized Guest Molecules

Pressures up to 0.8 GPa have been
used to squeeze a range of sterically
“oversized” C5–C8 alkane guest molecules into
the cavities of a small-pore Sc-based metal–organic framework.
Guest inclusion causes a pronounced reorientation of the aromatic
rings of one-third of the terephthalate linkers, which act as “torsion
springs”, resulting in a fully reversible change in the local
pore structure. The study demonstrates how pressure-induced guest
uptake can be used to investigate framework flexibility relevant to “breathing”
behavior and to understand the uptake of guest molecules in MOFs relevant
to hydrocarbon separation.