Guest‐Induced Structural Transformations in a Porous Halogen‐Bonded Framework

Structural evidence obtained from in situ X‐ray diffraction shows that halogen bonding is responsible for the formation of a dynamic porous molecular solid. This material is surprisingly robust and undergoes reversible switching of its pore volume by activation or by exposure to a series of gases of different sizes and shapes. Volumetric gas sorption and pressure‐gradient differential scanning calorimetry (P‐DSC) data provide further mechanistic insight into the breathing behavior.