Molecular-Squeeze Triggers Guest Desorption from Sponge-Like Macrocyclic Crystals

Abstract

Desorption in conventional porous sorbents often employ external forces including inert gas blowing, heating, vacuum treatment to trigger guest release through competitive intermolecular interactions. We here report an unprecedented molecular–squeeze triggered guest release behavior from sponge–like macrocyclic crystals. The crystals function as typical sponge to include guest molecules within their microscopic voids that are adaptively formed, thus acting as adsorbents for toluene/pyridine separations. Intriguingly, vaporized ethyl acetate molecules trigger the guest release from the crystals without entering the pores or voids of the adsorbent to replace the guest. Instead, they work as external forces applied directly onto the crystals themselves, squeezing the materials to close the voids and release the guest molecules. Various experimental techniques as well as molecular dynamics simulations reveal the mechanism of the molecular–squeeze induced guest release procedure. The vapor–regenerated crystals can be recycled multiple times without the loss of separation performance. Compared with conventional guest release procedure, this method is manipulated in a mild condition, showing the potential in saving cost and energy.