Gradient Isotactic Multiblock Polylactides from Aluminum Complexes of Chiral Salalen Ligands

Aluminum complexes of enantiomerically pure aminomethylpyrrolidine-based salalen ligands and their application in the stereoselective polymerization of lactide are described. Poly­(lactic acid) featuring the new gradient isotactic multiblock microstructure was synthesized by isoselective catalysts, which operate by a combination of enantiomorphic-site and chain-end control mechanisms.