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Crystalline CO(2)-based polycarbonates prepared from racemic catalyst through intramolecularly interlocked assembly
The crystalline stereocomplexed polycarbonates can be prepared by mixing enantiopure polymers with opposite configuration, which derived from the asymmetric copolymerization with CO(2) using enantiopure catalyst or/and chiral epoxides. Herein, we develop a powerful strategy for producing crystalline...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Pub. Group
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4634215/ https://www.ncbi.nlm.nih.gov/pubmed/26469884 http://dx.doi.org/10.1038/ncomms9594 |
Sumario: | The crystalline stereocomplexed polycarbonates can be prepared by mixing enantiopure polymers with opposite configuration, which derived from the asymmetric copolymerization with CO(2) using enantiopure catalyst or/and chiral epoxides. Herein, we develop a powerful strategy for producing crystalline intramolecular stereocomplexed polycarbonates from racemic catalysts, which possess similar thermal stability and crystalline behaviour in comparison with the stereocomplexes by mixing opposite enantiopure polymers. Living polymer chains shuttle between catalyst molecules with different configurations to produce diastereomeric active species which is suggested to be responsible for the formation of isotactic multiblock polycarbonates in racemic bimetallic cobalt catalyst-mediated stereoselective copolymerization of CO(2) and meso-epoxides. Solid-state NMR spectroscopy study suggests that the interaction in the carbonyl and methine regions is responsible for the strong crystallization capacity and compact package structure in the crystalline polycarbonates. |
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