Aromatizing olefin metathesis by ligand isolation inside a metal-organic framework

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Extended porous frameworks offer unique environments for chemical transformations.
• Metal-organic frameworks (MOFs) can be functionalized post-synthesis to introduce new properties.
• Olefin metathesis is a powerful tool for carbon-carbon bond formation.

Purpose of the Study:

• To investigate the catalytic potential of an extended porous framework for aromatizing ring-closing metathesis.
• To synthesize a noninterpenetrated MOF (SALEM-14) and convert it into a PAH-containing MOF (PAH-MOF-1).
• To explore the selective formation and release of polycyclic aromatic hydrocarbons (PAHs) within a MOF structure.

Main Methods:

• Solvent-assisted linker exchange (SALE) was employed to construct the initial framework.
• Post-synthesis modification using olefin metathesis was performed on the SALEM-14 framework.
• The Hoveyda-Grubbs catalyst was utilized for the metathesis reaction.
• Acidic conditions in dimethylsulfoxide were used to release the PAH products.

Main Results:

• The noninterpenetrated SALEM-14 framework was successfully synthesized.
• Catalytic conversion of SALEM-14 yielded PAH-MOF-1 with polycyclic aromatic hydrocarbon pillars.
• The MOF structure prevented intermolecular olefin metathesis, favoring intramolecular cyclization.
• Polycyclic aromatic hydrocarbons were successfully released from the framework.

Conclusions:

• Extended porous frameworks can host and direct complex chemical reactions like aromatizing ring-closing metathesis.
• SALEM-14 serves as a platform for synthesizing PAH-MOF-1, demonstrating the utility of SALE and post-synthesis modification.
• The MOF architecture plays a crucial role in controlling reaction pathways and enabling selective product formation and release.