Metal-Organic Framework/Organocatalyst Combinations as Powerful Multicatalytic Systems for Aerobic Oxidations

Area of Science:

• Catalysis
• Materials Science
• Organic Chemistry

Background:

• Aerobic oxidation is a sustainable method for synthesizing organic compounds.
• Achieving high selectivity in aerobic oxidation reactions remains a significant challenge.
• Biomimetic systems can mimic enzymatic processes for enhanced catalytic efficiency.

Purpose of the Study:

• To develop a tunable, semiheterogeneous biomimetic multicatalytic system for selective aerobic oxidation.
• To mimic the cooperative action of enzyme/coenzyme pairs using Metal-Organic Frameworks (MOFs) and organocatalysts.
• To demonstrate the versatility of this approach for various challenging oxidation reactions.

Main Methods:

• Utilized a Zr-MOF-808/1,8-dihydroxynaphthalene system for aniline oxidation.
• Employed electron transfer at the MOF/organocatalyst interface to generate reactive oxygen species.
• Expanded the methodology to include thiol and benzylamine oxidations using different MOFs and co-catalysts.

Main Results:

• Achieved excellent yields and selectivity in the aerobic oxidation of anilines to azoxybenzenes.
• Demonstrated successful aerobic oxidation of thiols to disulfides by altering the co-catalyst.
• Showcased the aerobic oxidation of benzylamines to coupled products using a Ti-based MOF (Ti-MIL-125).

Conclusions:

• The MOF/organocatalyst multicatalytic system offers a sustainable and highly selective route for challenging aerobic oxidations.
• This biomimetic approach operates under mild conditions without external stimuli like light.
• Highlights the potential of MOF/organocatalyst combinations for green chemistry applications.