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Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
Published on: December 16, 2022
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Tuning the Reactivity of Cyclopropenes from Living Ring-Opening Metathesis Polymerization (ROMP) to Single-Addition
Jessica K Su1, Zexin Jin1, Rui Zhang2
1Department of Chemistry, Stanford University, Stanford, CA, 94305, USA.
Angewandte Chemie (International Ed. in English)
|October 2, 2019
Summary
Cyclopropenes (CPEs) exhibit versatile reactivity in ring-opening metathesis polymerization (ROMP). Modifying CPE substituents switches ROMP from living to single-addition or alternating, offering new copolymer scaffolds.
Area of Science:
- Polymer Chemistry
- Organic Synthesis
Background:
- Ring-opening metathesis polymerization (ROMP) is a crucial living polymerization technique.
- Cyclopropenes (CPEs) are an underexplored class of monomers for ROMP.
Purpose of the Study:
- To investigate the reactivity of substituted cyclopropenes in ROMP.
- To explore the influence of substituent modifications on polymerization modes.
- To develop new functionalizable alternating copolymers.
Main Methods:
- Synthesis of 1-(benzoyloxymethyl)cyclopropene derivatives with methyl and phenyl substituents.
- Ring-opening metathesis polymerization using ruthenium catalysts.
- Analysis of polymerization mechanisms, including steric and chelation effects.
Main Results:
- A simple phenyl-for-methyl substitution on CPEs dramatically altered ROMP behavior.
- Switching from living polymerization to selective single-addition or living alternating ROMP was observed.
- Steric repulsions and potential chelation effects at the ruthenium center influenced propagation rates.
Conclusions:
- Cyclopropenes are versatile monomers for ROMP, enabling diverse polymerization outcomes.
- Mechanistic insights were gained for designing monomers with unique reactivity, like single-addition.
- A new scaffold for functionalizable alternating copolymers with controlled molecular weights and low dispersity was generated.
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