Anhydride Post-Synthetic Modification in a Hierarchical Metal-Organic Framework

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Metal-organic frameworks (MOFs) are versatile porous materials crucial for various applications.
• Post-synthetic modification (PSM) enhances MOF properties by functionalizing organic linkers.
• Existing PSM methods have limitations in incorporating diverse molecules and complexes.

Purpose of the Study:

• To establish a novel platform for PSM of MOFs using an anhydride functional group.
• To leverage the reactivity of anhydrides and hierarchical porosity for MOF functionalization.
• To demonstrate the platform's capability in incorporating a wide range of guest molecules and metal complexes.

Main Methods:

• Introduction of an anhydride functional group into a hierarchically porous MOF (MIL-121).
• Covalent binding of various guest molecules (alcohols, amines, thiols) to the anhydride group.
• Incorporation of noble metal (Pt(II)/Pt(IV)) complexes into the functionalized MOF.
• Demonstration of hierarchical pore utilization for guests of varying sizes.

Main Results:

• The anhydride-functionalized MOF (MIL-121) exhibited high reactivity towards diverse guest molecules.
• Hierarchical pores facilitated the incorporation of small (methanol) to large (polyaromatic amines) guest species.
• Noble metal complexes, including Pt(II)/Pt(IV), were successfully integrated into the MOF structure.
• A Pt-based electrocatalyst was synthesized, showing excellent activity for the oxygen reduction reaction (ORR).

Conclusions:

• A novel and effective PSM platform for MOFs based on anhydride functionalization has been developed.
• This approach offers a versatile strategy for incorporating diverse organic molecules and metal complexes.
• The developed MOF-based electrocatalyst demonstrates significant potential for applications in fuel cells and energy storage.