Pd Clusters on Schiff Base-Imidazole-Functionalized MOFs for Highly Efficient Catalytic Suzuki Coupling Reactions

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Subnanometer noble metal clusters offer high catalytic activity due to abundant low-coordinated atoms.
• High surface free energy in small clusters leads to aggregation, limiting their catalytic applications.
• Developing stable, highly dispersed metal clusters is crucial for efficient catalysis.

Purpose of the Study:

• To synthesize novel Schiff base-imidazole-functionalized metal-organic frameworks (MOFs).
• To construct highly dispersed palladium (Pd) clusters on these functionalized MOFs.
• To evaluate the catalytic performance of the resulting Pd clusters in Suzuki coupling reactions.

Main Methods:

• Post-synthetic modification of MOFs to introduce Schiff base-imidazole functionalities.
• Immobilization of highly dispersed palladium (Pd) clusters onto the functionalized MOFs.
• Catalytic testing of the Pd/MOF composite in Suzuki coupling reactions under mild conditions.

Main Results:

• Successfully synthesized Schiff base-imidazole-functionalized MOFs.
• Constructed highly dispersed Pd clusters with an average size of 1.5 nm on the functional MOFs.
• Achieved excellent catalytic activity in Suzuki coupling, yielding >99% biaryl.
• Demonstrated catalyst reusability over six cycles without activity loss.

Conclusions:

• The functionalized MOFs effectively stabilize small Pd clusters, preventing aggregation.
• The surface functional groups promote the formation of metallic Pd(0) clusters, enhancing catalytic performance.
• This approach offers a stable and reusable catalyst for efficient Suzuki coupling under mild conditions.