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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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Zinc calixarene complexes for the ring opening polymerization of cyclic esters
Mark J Walton1, Simon J Lancaster, Joseph A Wright
1Energy Materials Laboratory, School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK.
Dalton Transactions (Cambridge, England : 2003)
|October 30, 2014
Summary
New zinc complexes with calixarene ligands were synthesized and tested for ring-opening polymerization. Compound 4, featuring a zinc silylamide, showed high activity in polymerizing lactide at room temperature.
Area of Science:
- Organometallic Chemistry
- Polymer Chemistry
- Supramolecular Chemistry
Background:
- Calixarenes are versatile macrocyclic hosts with tunable properties.
- Zinc complexes are of interest for catalysis, particularly in polymerization reactions.
Purpose of the Study:
- To synthesize novel zinc complexes incorporating calixarene and oxacalixarene ligands.
- To investigate the catalytic activity of these complexes in ring-opening polymerization (ROP).
Main Methods:
- Synthesis of zinc complexes using various zinc precursors and calixarene ligands.
- Structural characterization of new complexes using X-ray crystallography.
- Evaluation of catalytic performance in ROP of ε-caprolactone and rac-lactide.
Main Results:
- Isolation and structural determination of four new zinc-calixarene complexes.
- Zinc complexes with Zn-C6F5 bonds showed poor pre-catalyst activity.
- Complex 4, [Zn{N(SiMe3)2}2L(1)], demonstrated high activity in ROP of rac-lactide, achieving 65% conversion at room temperature.
Conclusions:
- The nature of the zinc ligand significantly impacts catalytic activity in ROP.
- Zinc silylamide complexes with calixarene frameworks are promising catalysts for lactide polymerization.
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