Programmed Pore-Shape Fixing in a Soft Porous Molecular Crystal-Navigating the Phase Interconversion Landscape.

Pore-shape fixing effects (PSFEs) in soft porous crystals are a relatively unexplored area of materials chemistry. We report the PSFE in the prototypical dynamic van der Waals solid p-tert-butylcalix[4]arene (TBC4). Starting with the high-density guest-free phase, two porous shape-fixed phases were programmed using the stimuli of CO pressure and temperature.