Catalytic living ring-opening metathesis polymerization with Grubbs' second- and third-generation catalysts

Area of Science:

• Polymer Chemistry
• Organic Synthesis
• Materials Science

Background:

• Conventional living ring-opening metathesis polymerization (ROMP) requires stoichiometric ruthenium complexes, leading to high catalyst loadings for short polymers.
• High catalyst loadings increase costs and environmental impact due to the use of expensive and toxic ruthenium complexes.

Purpose of the Study:

• To develop a more economical and environmentally friendly method for living ROMP.
• To achieve living polymerization characteristics using only catalytic amounts of ruthenium complexes.

Main Methods:

• Utilized a reversible chain-transfer agent in conjunction with Grubbs' ruthenium complexes.
• Employed norbornene derivatives as monomers, including those with functional moieties like ferrocene, coumarin, and protected alcohols.
• Investigated a degenerative chain-transfer process to control polymerization.

Main Results:

• Successfully produced living ROMP polymers from norbornene derivatives using catalytic ruthenium complexes.
• Achieved excellent molecular weight control and narrow molecular weight dispersities.
• Demonstrated the ability to form block copolymers.
• Showcased the polymerization of functionalized monomers in a living fashion.

Conclusions:

• The developed method enables living ROMP with catalytic ruthenium, significantly reducing catalyst usage.
• This approach is more cost-effective and sustainable than traditional living ROMP methods.
• The technique allows for the synthesis of well-defined polymers with diverse functionalities.