Recyclable, Biobased Polycarbonates and Polyesters by Naphthoxy-Imine Zinc and Magnesium Complexes.

Naphthoxy-imine pyridine zinc and magnesium complexes were synthesized and fully characterized by nuclear magnetic resonance (NMR). In the presence of an alcohol as initiator, both complexes promoted the ring-opening polymerization (ROP) of L-lactide (L-LA), ε-caprolactone (ε-CL), β-butyrolactone (β-BL), trimethylene carbonate (TMC), and 1-methyl trimethylene carbonate (Me-TMC), which was purposely synthesized from CO and the appropriate diol. The zinc complex exhibited notably high activity, particularly in the polymerization of lactide and TMC, and was subsequently employed in the synthesis of polytrimethylene carbonate-based diblock and random copolymers with both ε-CL and L-LA. Furthermore, the zinc complex demonstrated its ability to close the life cycle of the synthesized materials by successfully depolymerizing both polytrimethylene carbonate (PTMC) and its copolymers.