Hydrogen Bond Donors in the Catalytic Pocket: The Case of the Ring-Opening Polymerization of Cyclic Esters Catalyzed by an Amino-Propoxide Aluminum Complex.

A new aluminum complex (NSO)AlMe featuring a hydrogen bond donor on the ligand backbone has been synthesized via the reaction of AlMe with 1-((2-(isopropylamino)phenyl)thio)propan-2-ol (NSO-H) and spectroscopically characterized. In the complex, the aluminum atom is in a distorted tetrahedral coordination sphere determined by the anionic oxygen and neutral nitrogen atoms of the ligand and by the two carbon atoms of the alkyl groups. After proper activation, the complex (NSO)AlMe was able to promote the ring-opening polymerization of -, -lactide, -caprolactone and --butyrolactone.