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Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
Published on: November 21, 2017
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CO2-Based Polycarbonates through Ring-Opening Polymerization of Cyclic Carbonates Promoted by a NHC-Based Zinc
Federica Tufano1,2, Claudia Napolitano1,2, Mina Mazzeo1,2
1Department of Chemistry and Biology "Adolfo Zambelli" University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy.
Biomacromolecules
|June 25, 2024
Summary
A novel N-heterocyclic carbene zinc catalyst enables controlled ring-opening polymerization of trimethylene carbonate (TMC) to poly(trimethylene carbonate) (PTMC). This method yields polymers with tunable molecular mass and low dispersity, minimizing side reactions.
Area of Science:
- Polymer Chemistry
- Organometallic Chemistry
- Materials Science
Background:
- Ring-opening polymerization (ROP) is crucial for synthesizing biodegradable polymers.
- N-heterocyclic carbene (NHC) complexes offer tunable catalytic properties.
- Controlled polymerization of cyclic carbonates remains a challenge.
Purpose of the Study:
- To develop an effective catalyst for the ROP of trimethylene carbonate (TMC).
- To achieve controlled molecular mass and low dispersity in poly(trimethylene carbonate) (PTMC) synthesis.
- To explore the catalyst's ability to polymerize substituted cyclic carbonates and form block copolymers.
Main Methods:
- Utilized a backbone-substituted NHC zinc complex with alcohol initiators for ROP.
- Characterized PTMC using MALDI-ToF and NMR spectroscopy.
- Investigated polymerization kinetics and mechanism in solution.
- Synthesized and polymerized substituted cyclic carbonates derived from renewable feedstocks.
- Prepared polycarbonate/polyether and polycarbonate/polylactide block copolymers.
Main Results:
- Achieved controlled ROP of TMC to PTMC with molecular mass (2500–10000) and low dispersity (Đ ≈ 1.2).
- Demonstrated the formation of PTMC with various end-groups, including telechelic polymers, by changing alcohol initiators.
- Confirmed the controlled/living nature of the ROP system, minimizing transesterification side reactions.
- Showcased the polymerization of substituted cyclic carbonates with good regioselectivity (Xreg up to 0.92) for 2-Me TMC.
- Successfully synthesized triblock and di-/triblock copolymers using PEG and polylactide.
Conclusions:
- The NHC zinc complex is a highly effective catalyst for controlled ROP of TMC.
- The system allows for precise control over polymer architecture, molecular weight, and end-group functionality.
- This catalytic approach is versatile, enabling the synthesis of complex polymer structures from renewable resources.
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