Abstract
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 language | English |
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Pages (from-to) | 17183-17189 |
Number of pages | 7 |
Journal | Chemistry - A European Journal |
Volume | 26 |
Issue number | 71 |
DOIs | |
State | Published - 18 Dec 2020 |
Keywords
- isoselectivity
- living polymerization
- magnesium
- poly(lactic acid)
- ring-opening polymerization
All Science Journal Classification (ASJC) codes
- Catalysis
- Organic Chemistry