Recently we reported a series of highly active Al(III)-complexes bearing a catalen ligand support for lactide polymerisation, observing unprecedented activity in the melt.35 Herein we report diversification of the metal to furnish a series of well-defined dimeric Zn(II)- and Mg(II)-complexes, which were fully characterised by X-ray crystallography and NMR spectroscopy. The production of biocompatible atactic PLA from rac-LA in solution and under industrially preferred solvent-free conditions was demonstrated, typically observing good activity and Mn control with a broad range of dispersities (Đ = 1.08 – 2.04). Mg(II)-complexes were shown to facilitate the relatively mild methanolysis of PLA, achieving up to 64% conversion to Me-LA within 8 h at 80 °C in THF. Further kinetic analysis found [Mg(1,3)]2 to have kapp values of 0.628 ± 0.0536 {4 wt% cat. loading} and 0.265 ± 0.0193 h-1 {8 wt% cat. loading} respectively for the rate of consumption of PLA. Preliminary work extended polymer scope to PET from various sources, demonstrating catalyst versatility.
Original languageEnglish
JournalPolymer Chemistry
Early online date13 Jan 2021
Publication statusE-pub ahead of print - 13 Jan 2021

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