Tandem mechanochemical engineering yields highly crystalline metal-organic frameworks

Area of Science:

• Materials Science
• Chemical Engineering
• Crystallography

Background:

• Highly crystalline metal-organic frameworks (MOFs) formation requires reversible metal-ligand (M-L) bonds for defect annealing.
• Solvothermal synthesis is common, but mechanochemical synthesis offers a greener alternative.
• Solid-state mechanochemical reactions limit molecular mobility, hindering defect annealing and crystallization.

Purpose of the Study:

• To develop a tandem mechanochemical strategy for synthesizing highly crystalline MOFs.
• To investigate the cooperative dynamics between dual reversible bonds (M-L and imine condensation).
• To overcome limitations of solid-state mechanochemical reactions for MOF crystallization.

Main Methods:

• Employing a tandem mechanochemical engineering strategy.
• Incorporating imine condensation alongside traditional M-L coordination.
• Utilizing high-connectivity ligand analogues with irreversible covalent linkages for comparison.

Main Results:

• The synergistic effect of dual reversible bonds enhances crystallization kinetics.
• Efficient mechanochemical synthesis of MOFs with improved crystallinity under ambient conditions was achieved.
• Ligands with irreversible linkages failed to produce quality crystalline MOF phases under mechanochemical conditions.

Conclusions:

• Tandem mechanochemical strategy enables efficient synthesis of highly crystalline MOFs.
• Cooperative dynamics between M-L and imine reversible bonds are crucial for MOF quality.
• This approach offers a greener and more effective route for MOF production, especially for high-connectivity ligands.