Related Experiment Video
Updated: May 8, 2026
05:48
Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
Published on: November 21, 2017
Ring-opening polymerization with Zn(C6F5)2-based Lewis pairs: original and efficient approach to cyclic polyesters
Estefanía Piedra-Arroni1, Catherine Ladavière, Abderrahmane Amgoune
1Laboratoire Hétérochimie Fondamentale et Appliquée, UMR CNRS 5069, Université de Toulouse , F-31062 Toulouse, France.
Journal of the American Chemical Society
|August 31, 2013
Summary
Dual catalyst systems using zinc and organic bases enable controlled polymerization of lactide and caprolactone. This method produces high molecular weight cyclic polyesters and cyclic block copolymers.
Area of Science:
- Polymer Chemistry
- Organometallic Chemistry
Background:
- Ring-opening polymerization (ROP) is a key method for synthesizing polyesters.
- Controlled ROP is crucial for tailoring polymer properties and creating complex architectures.
- Lewis acid/base pairs offer unique activation mechanisms for monomer polymerization.
Purpose of the Study:
- To investigate dual catalyst systems for controlled ROP of lactide and ε-caprolactone.
- To explore the cooperative effects of zinc complexes and organic bases in polymerization.
- To synthesize well-defined cyclic polyesters and block copolymers.
Main Methods:
- Utilizing dual systems comprising Zn(C6F5)2 and organic bases (amines, phosphines).
- Performing controlled ring-opening polymerization of lactide and ε-caprolactone.
- Employing chain-extension techniques for block copolymer synthesis.
Main Results:
- The dual systems effectively promoted controlled ROP of both monomers.
- Well-defined cyclic polyesters with high molecular weights were obtained.
- Efficient chain-extension led to the formation of cyclic block copolymers.
Conclusions:
- Cooperative Lewis pairs of Zn(C6F5)2 and organic bases are highly effective for controlled ROP.
- This approach provides access to high molecular weight cyclic polyesters and block copolymers.
- The developed method offers a pathway to advanced polymer architectures.
Related Concept Videos
01:16Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...
01:17Ziegler–Natta Chain-Growth Polymerization: Overview
Ziegler–Natta polymerization is another form of addition or chain‐growth polymerization used for synthesizing linear polymers over branched polymers. The catalyst used for polymerization is the Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, who developed it in 1953. This catalyst is an organometallic complex of titanium tetrachloride and triethyl aluminum, with the active form of the catalyst being an alkyl titanium compound. Using the Ziegler–Natta catalyst, high molecular...
00:57Cationic Chain-Growth Polymerization: Mechanism
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the generated carbocation,...
02:26Base-Catalyzed Ring-Opening of Epoxides
Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...
01:13Olefin Metathesis Polymerization: Overview
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
02:35Free-Radical Chain Reaction and Polymerization of Alkenes
The conversion of alkenes to macromolecules called polymers is a reaction of high commercial importance. The structure of the polymer is defined by a repeating unit, while the terminal groups are considered insignificant. The average degree of polymerization represents the number of repeating units in the polymer molecule and is denoted by the subscript n.