Bis(imino)phenoxide complexes of zirconium: synthesis, structural characterization and solvent-free ring-opening polymerization of cyclic esters and lactides

Bis(imino)phenoxide complexes of zirconium possess spectacular reactivity towards the solvent-free polymerization of cyclic ester monomers and lactides. Polymerization of lactide is living and the resulting product has exceptionally high number average molecular weights (M-n). Polymerization of b-butyrolactone gives syndiotactic poly(3-hydroxybutyrate) with good M-n and molecular weight distribution (MWD).