Thermolabile Cross-Linkers for Templating Precise Multicomponent Metal-Organic Framework Pores

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Multicomponent metal-organic frameworks (MOFs) offer potential for mimicking enzyme active sites.
• Current strategies lack the structural versatility and molecular precision required for complex active site replication.

Purpose of the Study:

• To develop a general method for templating functional groups within MOF pores.
• To achieve greater structural versatility and molecular precision in MOF design.
• To create precisely positioned functional groups for building complex cooperative active sites.

Main Methods:

• Utilizing thermolabile ligand cross-linkers for functional group templating.
• Employing tertiary ester-based cross-linkers for installing carboxylic acid pairs.
• Demonstrating framework incorporation and thermolysis using mesoporous, terphenyl expanded MOF-74 analogues.
• Cleaving ester linkages via microwave heating to reveal free carboxylic acids.

Main Results:

• Successfully synthesized and incorporated tertiary ester cross-linkers into MOF-74 analogues.
• Demonstrated the cleavage of tertiary ester linkages upon microwave heating, revealing free carboxylic acids.
• Modeling studies showed precise placement of carboxylic acids (∼7 Å apart) in a single configuration within pore channels when using short cross-linkers.

Conclusions:

• A general method for templating functional groups within MOF pores using thermolabile cross-linkers has been established.
• Precisely positioned carboxylic acid pairs serve as valuable synthetic handles for constructing complex cooperative active sites.
• This approach enhances structural versatility and molecular precision in MOF design, paving the way for advanced functional materials.