Ultradynamic Isoreticularly Expanded Porous Organic Crystals

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Nanotechnology

Background:

• Porous organic materials with dynamic frameworks offer advanced adsorption and separation capabilities.
• Porous hydrogen-bonded crosslinked organic frameworks (H_COFs) exhibit guest-responsive size changes but have limited void spaces.
• Existing H_COFs have restricted framework dynamics due to limited void sizes.

Purpose of the Study:

• To synthesize H_COFs with unprecedented solvent-induced size expansion capabilities.
• To overcome the limitations of void size in H_COFs for enhanced framework dynamics.
• To explore the potential of these dynamic frameworks for encapsulating large guest molecules.

Main Methods:

• Isoreticular co-crystallization of complementary hydrogen-bonding building blocks.
• Thiol-ene/yne single-crystal-to-single-crystal transformations for crosslinking.
• Solvent-induced expansion and methanol-induced contraction experiments.

Main Results:

• Synthesized H_COFs with enhanced chemical durability, high crystallinity, and extraordinary framework dynamics.
• H_COF-104 crystals expanded up to 300% in DMF within 1 minute.
• Demonstrated adsorption of guests larger than crystalline pore sizes, followed by encapsulation via contraction.

Conclusions:

• Developed H_COFs with significant, solvent-triggered size expansion, overcoming previous void limitations.
• These dynamic frameworks enable the capture and encapsulation of large guest molecules.
• Presents new avenues for guest encapsulation and targeted delivery applications.