Solvent-Driven Dynamics: Crafting Tailored Transformations of Cu(II)-Based MOFs.

Area of Science:

• Materials Science
• Chemistry
• Chemical Engineering

Background:

• Metal-organic frameworks (MOFs) are crystalline porous polymers studied for gas uptake.
• Interpenetrated MOFs offer enhanced stability and smaller micropores for capturing nonpolar molecules.
• Ethane/ethylene separation is a critical industrial process.

Purpose of the Study:

• To explore solvent-assisted reversible interpenetration and deinterpenetration of a Cu(II)-based MOF.
• To investigate the adsorptive separation of ethane and ethylene using these MOFs.
• To identify factors influencing gas uptake and selectivity in MOFs.

Main Methods:

• Solvent-assisted synthesis and transformation of MOF-143 (noninterpenetrated) and MOF-14 (doubly interpenetrated).
• Utilized protic solvents (water, methanol, ethanol) for interpenetration and pyridine for deinterpenetration.
• Gas adsorption/desorption experiments to evaluate ethane and ethylene uptake and selectivity.

Main Results:

• Interpenetrated MOF-14 showed higher ethane and ethylene uptakes than noninterpenetrated MOF-143 due to narrower micropores.
• Pristine MOF-14 exhibited higher ethane selectivity than MOF-14 derived from MOF-143.
• The 'fraction of micropore volume' was identified as a critical factor for ethane uptake.

Conclusions:

• Controlled interpenetration and deinterpenetration of MOFs via solvent-assisted strategies are feasible.
• Interpenetrated MOFs with narrower micropores are promising for selective nonpolar gas capture.
• Optimizing MOF crystal size, micropore characteristics, and crystallinity is crucial for efficient gas separation.