Hysteresis in the gas sorption isotherms of metal-organic cages accompanied by subtle changes in molecular packing.

Structural deformation in response to gas sorption is rarely observed for porous molecular solids, when compared to porous framework materials. Here, we describe the effect of chemical modification on the exterior of lantern-type metal-organic cages on the emergence and then disappearance of cooperative gas uptake. The results suggest that supramolecular design of ligands can be used to reveal this behaviour.