Isoselective Polymerization of rac-Lactide by Highly Active Sequential {ONNN} Magnesium Complexes

Tomer Rosen, Jitendrasingh Rajpurohit, Sophia Lipstman, Vincenzo Venditto, Moshe Kol*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The coordination chemistry and the activities in the ring-opening polymerization catalysis of racemic lactide (LA) of magnesium complexes of a series of {ONNN}-type sequential monoanionic ligands are described. All ligands include pyridyl and substituted-phenolate as peripheral groups. The ligands bearing either chiral or meso-bipyrrolidine cores led to single diastereomeric complexes, whereas the ligands bearing a diaminoethane core led to diastereomer mixtures. All {ONNN}Mg-X complexes [X=Cl, HMDS (hexamethyldisilazide)] led to highly active and isoselective catalysts. The complexes bearing the chiral bipyrrolidine core exhibited the highest activities (full consumption of 5000 equiv. of rac-LA at RT within 5 min) and highest isoselectivities (Pm=0.91), as well as a living character. The complexes of the meso-bipyrrolidine based ligands were almost as active and slightly less stereoselective, while those of the diaminoethane based ligands exhibited reduced activities and isoselectivities.

Original languageEnglish
Pages (from-to)17183-17189
Number of pages7
JournalChemistry - A European Journal
Issue number71
StatePublished - 18 Dec 2020


  • isoselectivity
  • living polymerization
  • magnesium
  • poly(lactic acid)
  • ring-opening polymerization


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