Engineering Switchable Rotors in Molecular Crystals with Open Porosity

The first example of a porous molecular crystal containing rotors is presented. The permanently porous crystal architecture is sustained by rotor-bearing molecular rods which are connected through charge-assisted hydrogen bonds. The rotors, as fast as 108 Hz at 240 K, are exposed to the crystalline channels, which absorb CO2 and I2 vapors at low pressure. The rotor dynamics could be switched off and on by I2 absorption/desorption, showing remarkable change of material dynamics by the interaction with gaseous species and suggesting the use of molecular crystals in sensing and pollutant management.