![Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F51444.jpg&w=3840&q=50)
Synthesis of Optically Active Polystyrene Catalyzed by Monophosphine Pd Complexes
Matthieu Jouffroy1,2, Dominique Armspach2, Dominique Matt2
1Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, 226-8503, Japan.
Angewandte Chemie (International Ed. in English)
|May 25, 2016
Summary
Cationic palladium complexes with cyclodextrins catalyze styrene polymerization, forming CO-free polymers. These polymers exhibit optical activity due to stereoregular sequences in the atactic material.
Area of Science:
- Coordination chemistry
- Polymer science
- Catalysis
Background:
- Cationic palladium(II) complexes are explored as catalysts in polymerization reactions.
- Cyclodextrins (CDs) are used as ligands to modify catalyst properties.
- Styrene polymerization is a fundamental process in polymer chemistry.
Purpose of the Study:
- To investigate the catalytic activity of cationic Pd(II) monophosphine complexes derived from cyclodextrins in styrene homopolymerization.
- To understand the role of carbon monoxide (CO) in the catalytic cycle.
- To characterize the resulting polystyrene for structural and optical properties.
Main Methods:
- Synthesis of cationic Pd(II) monophosphine complexes incorporating α- and β-cyclodextrins.
- Homopolymerization of styrene under carbon monoxide pressure.
- (13)C NMR spectroscopy using (13)C-enriched CO to study CO coordination.
- Characterization of the resulting polymers for tacticity and optical activity.
Main Results:
- The cyclodextrin-derived palladium complexes effectively catalyze styrene homopolymerization.
- Despite reversible CO coordination observed via (13)C NMR, the polymerization yields CO-free polystyrene.
- The synthesized polystyrene exhibits optical activity, indicating the presence of stereoregular sequences within an atactic polymer chain.
Conclusions:
- Cationic Pd(II)-cyclodextrin complexes are efficient catalysts for producing CO-free polystyrene.
- The presence of stereoregular sequences, despite an overall atactic structure, imparts optical activity to the polymer.
- This study highlights the potential of cyclodextrin-modified palladium catalysts in controlled polymerization.
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