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Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
Published on: November 29, 2018
Cis-selective ring-opening metathesis polymerization with ruthenium catalysts.
Benjamin K Keitz1, Alexey Fedorov, Robert H Grubbs
1Arnold and Mabel Beckman Laboratories of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
Journal of the American Chemical Society
|January 14, 2012
Summary
Ruthenium-based catalysts enable cis-selective ring-opening metathesis polymerization of cyclic alkenes. Polymer cis content, reaching 96%, is tunable via monomer structure and polymerization temperature control.
Area of Science:
- Polymer Chemistry
- Organometallic Chemistry
- Catalysis
Background:
- Ring-opening metathesis polymerization (ROMP) is a versatile method for polymer synthesis.
- Achieving high cis-selectivity in ROMP is crucial for tailoring polymer properties.
- Ruthenium-based catalysts offer tunable reactivity and selectivity in metathesis reactions.
Purpose of the Study:
- To report the cis-selective ring-opening metathesis polymerization of various monocyclic alkenes and norbornene-type monomers.
- To investigate the influence of monomer structure and temperature on polymer cis content.
- To demonstrate the efficacy of a C-H activated ruthenium-based catalyst for controlled polymerization.
Main Methods:
- Utilized a C-H activated, ruthenium-based metathesis catalyst.
- Performed ring-opening metathesis polymerization on diverse monocyclic alkenes, norbornene, and oxanorbornene derivatives.
- Varied polymerization temperature and monomer structure to study their effects on polymer stereochemistry.
Main Results:
- Achieved cis-selective ring-opening metathesis polymerization of the studied monomers.
- Demonstrated that the cis content of the resulting polymers is significantly influenced by monomer structure and reaction temperature.
- Obtained polymers with a high cis content, up to 96%, by optimizing polymerization conditions, specifically by lowering the temperature.
Conclusions:
- The developed ruthenium-based catalyst effectively promotes cis-selective ROMP.
- Polymer stereochemistry in ROMP can be precisely controlled by adjusting monomer design and reaction temperature.
- Lowering polymerization temperature is a key strategy for maximizing cis-selectivity in ROMP.
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