Tuning the Connectivity, Rigidity, and Functionality of Two-Dimensional Zr-Based Metal-Organic Frameworks

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) offer tunable properties for various applications.
• Zirconium-based MOFs (Zr-MOFs) are known for their stability and versatility.
• Controlling the node connectivity in MOFs is crucial for tailoring their structure and function.

Purpose of the Study:

• To synthesize and characterize novel, highly stable Zr-based MOFs.
• To investigate the tunability of Zr₆ node connectivity using specific linkers.
• To explore the potential of these MOFs as platforms for catalysis.

Main Methods:

• Synthesis of Zr-based MOFs utilizing bowl-shaped tetratopic linkers.
• Structural analysis to determine node connectivities (e.g., 8-c, 4-c, 10-c).
• One-pot synthesis and postsynthetic linker installation strategies.
• Evaluation of thermal stability and temperature-dependent flexibility.
• Postsynthetic metalation for catalytic applications (Heck coupling).

Main Results:

• Development of highly stable, two-dimensional Zr-based MOFs.
• Demonstration of tunable Zr₆ node connectivity from 8-c to 4-c via linker steric hindrance.
• Achieved 10-c connectivity by incorporating secondary linear dicarboxylate linkers.
• Enhanced rigidity, thermal stability, and controlled temperature-dependent flexibility.
• Successful postsynthetic metalation with Pd(II) for Heck coupling catalysis.

Conclusions:

• Novel Zr-based MOFs with tunable node connectivity were successfully synthesized.
• The steric bulk of nonplanar linkers and secondary linker insertion are effective strategies for controlling framework topology.
• These MOFs exhibit improved thermal stability and flexibility, and serve as effective platforms for catalytic reactions.