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

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Adsorption Science

Background:

• Conventional porous sorbents rely on external forces like heating or vacuum for guest molecule release.
• Developing novel, energy-efficient desorption methods is crucial for sustainable separation technologies.

Purpose of the Study:

• To report a new molecular-squeeze triggered guest release mechanism from macrocycle crystals.
• To demonstrate the potential of this method for toluene/pyridine separations and adsorbent regeneration.

Main Methods:

• Utilized sponge-like macrocycle crystals as adsorbents.
• Investigated guest release triggered by vaporized ethyl acetate (EA).
• Employed experimental techniques and molecular dynamics simulations to elucidate the mechanism.

Main Results:

• Ethyl acetate (EA) vapor induced guest release via a "molecular squeeze" effect on crystal surfaces.
• EA molecules did not enter the crystal pores, acting as an external force.
• The EA-regenerated crystals maintained separation performance after multiple cycles.

Conclusions:

• The molecular-squeeze mechanism provides a mild and energy-saving alternative for adsorbent regeneration.
• This supramolecular interaction-based release offers a novel approach for separation applications.
• The developed macrocycle crystals show promise for sustainable chemical separations.