Pore-Space-Partitioned Metal-Organic Frameworks with Acyclic Diene Linkers for C₂H₂/CO₂ Separation

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) are crucial for gas adsorption and separation.
• Isoreticular tuning is a key strategy for optimizing MOF properties.
• Conventional tuning methods often increase framework bulkiness.

Purpose of the Study:

• To explore a new isoreticular tuning pathway using acyclic diene linkers.
• To reduce framework bulkiness in pore-space-partitioned MOFs.
• To enhance acetylene (C2H2) and carbon dioxide (CO2) separation.

Main Methods:

• In situ ligand transformation of trans-butene-1,4-dicarboxylic acid (tbdc) to s-cis-trans, trans-muconate (scMA).
• Construction of a new series of scMA-based MOFs (scMA-pacs).
• Comparison of scMA-pacs with conformational isomer stMA-pacs and length-matched bdc-pacs.

Main Results:

• scMA-based frameworks showed reduced CO2 affinity and maintained high C2H2 capacity.
• InNi-scMA-pacs achieved a C2H2/CO2 capacity ratio of 3.2 at 298 K and 1 bar.
• Demonstrated superior performance in breakthrough separation compared to analogues.

Conclusions:

• Acyclic diene replacement is an effective isoreticular tuning strategy.
• This method optimizes pore environments for improved gas separation.
• The developed MOFs show promise for selective acetylene capture.