Microporous Lead-Organic Framework for Selective CO₂ Adsorption and Heterogeneous Catalysis

Area of Science:

• Materials Science
• Inorganic Chemistry
• Catalysis

Background:

• Metal-organic frameworks (MOFs) are promising porous materials for gas storage and catalysis.
• Developing MOFs with high surface area and specific functionalities is crucial for advanced applications.
• The methanetetrabenzoate (MTB) ligand offers a versatile platform for MOF construction.

Purpose of the Study:

• Synthesize and characterize a novel MOF based on lead and the MTB ligand.
• Investigate the gas adsorption properties, particularly for carbon dioxide (CO2).
• Evaluate the catalytic performance of the MOF in Knoevenagel condensation reactions.

Main Methods:

• Solvothermal synthesis and single-crystal X-ray diffraction for structural characterization.
• Gas sorption analysis (Brunauer-Emmett-Teller) to determine surface area and adsorption capacity.
• Density functional theory (DFT) calculations to understand CO2 interactions.
• Heterogeneous catalysis experiments for Knoevenagel condensation.

Main Results:

• A novel microporous MOF, {[Pb4(μ8-MTB)2(H2O)4]·5DMF·H2O}n (1), was successfully synthesized.
• The desolvated MOF (1') exhibits a record high Brunauer-Emmett-Teller surface area of 980 m2·g-1 within the MTB group.
• Compound 1' demonstrated high CO2 uptake and selectivity over N2 and CH4, crucial for atmospheric CO2 capture.
• 1' showed excellent catalytic activity and selectivity in Knoevenagel condensation reactions, highlighting the role of accessible lead(II) sites.

Conclusions:

• The synthesized MOF possesses a unique structure with significant potential for gas adsorption and separation.
• The high CO2 selectivity of MOF 1' is promising for greenhouse gas mitigation strategies.
• The material's efficacy as a heterogeneous catalyst opens avenues for its use in green organic synthesis.