Light-Controlled Exposure/Blockage of Permanent Cavities in Metal-Organic Cages-Based Type II Porous Liquids

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Chemical Engineering

Background:

• Photoresponsive porous liquids (PPLs) modulate gas uptake via light.
• Existing PPLs alter photoresponsive motifs but not permanent pores.
• Controlling permanent pore accessibility in PPLs remains a challenge.

Purpose of the Study:

• To fabricate type II PPLs with light-tunable adsorption capacities.
• To investigate light-controlled exposure/blockage of permanent cavities.
• To enhance CO2 uptake performance in PPLs.

Main Methods:

• Synthesized a photoresponsive porous host (MOC-SO3Na-Azo) by modifying MOC-SO3Na with 3-phenylazopyridine.
• Dissolved the host in a bulky ionic liquid ([P6,6,6,14][Cl]) to form the PPL.
• Measured CO2 uptake under varying light conditions.

Main Results:

• Achieved high CO2 uptake (9.9 cm3 g-1) in the type II PPL (PPL-MSA), surpassing existing type II PPLs.
• Demonstrated a 49.3% change in CO2 uptake under different light conditions.
• Attributed the photoresponsive efficiency to light-induced exposure/blockage of permanent cavities.

Conclusions:

• Successfully fabricated type II PPLs with light-tunable permanent cavities.
• PPL-MSA exhibits significantly enhanced CO2 uptake and photoresponsive efficiency.
• This work presents a novel strategy for designing advanced porous materials.