High-pressure induced guest-mediated gate opening behaviour of the Co-based framework ZIF-67.

High-pressure single crystal X-ray diffraction has been used to probe framework–guest interactions in the Co-based metal–organic framework ZIF-67 during compression in 4 : 1 MeOH : EtOH and liquid nitrogen (LN₂) pressure-transmitting media. On increasing pressure, the structure undergoes a gate-opening phase transition, characterised by rotation of the 2-methylimidazolate ligand, at 1.57 GPa in MeOH : EtOH and at 0.43 GPa LN₂. Adsorption of N₂ occurred progressively with increasing pressure into 6 adsorption sites and resulted in the first documented instance of pressure-induced solvatochromism in ZIF-67. [ABSTRACT FROM AUTHOR]