Efficient Homodifunctional Bimolecular Ring-Closure Method for Cyclic Polymers by Combining RAFT and...

Area of Science:

• Polymer Chemistry
• Organic Synthesis
• Materials Science

Background:

• Traditional methods for cyclic polymer synthesis often require precise control over reactant stoichiometry.
• Achieving high yields of pure cyclic polymers via bimolecular ring-closure can be challenging.

Purpose of the Study:

• To develop an efficient, metal-free method for synthesizing cyclic polymers.
• To combine reversible addition-fragmentation chain transfer (RAFT) polymerization with a self-accelerating click reaction for polymer ring-closure.

Main Methods:

• Preparation of α,ω-homodifunctional linear polymers with azide terminals via RAFT polymerization and end-group modification.
• Utilizing sym-dibenzo-1,5-cyclooctadiene-3,7-diyne (DBA) as small linkers.
• Employing the self-accelerating double strain-promoted azide-alkyne click (DSPAAC) reaction for bimolecular ring-closure.

Main Results:

• Successfully synthesized well-defined cyclic polymers using the DSPAAC reaction.
• The self-accelerating nature of DSPAAC eliminated the need for equimolar amounts of polymer precursors and linkers.
• Efficient and convenient production of varied pure cyclic polymers was achieved, even with an excess of DBA linkers.

Conclusions:

• A novel, efficient, and metal-free homodifunctional bimolecular ring-closure method for cyclic polymer formation has been established.
• The developed method offers a significant advantage over traditional approaches by bypassing strict stoichiometric requirements.
• This strategy provides a versatile platform for the convenient synthesis of diverse cyclic polymers.