Metal-Organic Frameworks Stabilize Solution-Inaccessible Cobalt Catalysts for Highly Efficient Broad-Scope Organic...

Area of Science:

• Catalysis
• Materials Science
• Organic Chemistry

Background:

• Precious metal catalysts are essential but costly and unsustainable for chemical production.
• Earth-abundant metal catalysts are needed to replace precious metals for sustainable synthesis.
• Metal-organic frameworks (MOFs) offer a promising platform for designing novel catalysts.

Purpose of the Study:

• To design and synthesize robust, active, and reusable cobalt-based MOF catalysts.
• To explore the catalytic applications of these MOFs in hydrogenation and hydroboration reactions.
• To elucidate the mechanism of catalysis and understand the role of MOF structure.

Main Methods:

• Synthesis of cobalt-bipyridine and cobalt-phenanthroline based MOFs.
• Testing MOF catalysts in alkene hydrogenation, hydroboration, and C-H borylation reactions.
• Utilizing structural, computational, and spectroscopic techniques for mechanistic studies.

Main Results:

• MOF catalysts demonstrated high activity and stability in alkene hydrogenation with turnover numbers up to ~2.5 × 10^6.
• The catalysts were effective for various reactions including hydroboration and C-H borylation.
• Site isolation within MOFs prevented deactivation and stabilized reactive cobalt species.
• A novel catalytic mechanism involving a (bpy(•-))Co(I)(THF)2 ground state was proposed.

Conclusions:

• Cobalt-based MOFs are highly effective and reusable catalysts for sustainable chemical synthesis.
• MOFs provide a unique platform for developing new base-metal catalysts.
• The findings pave the way for broader applications of MOFs in catalysis.