Cationic zinc complexes: a new class of catalyst for living lactide polymerization at ambient temperature

Cationic zinc complexes of a bis(phosphinimine) pincer ligand have been prepared. Methylzinc and zinc-lactate complexes have been structurally characterized, and the latter is the first cationic metal complex to promote coordination-insertion polymerization of lactide at ambient temperature. This novel catalyst system is remarkably active and also exhibits living character. A detailed investigation of the kinetics and mechanism of the polymerization process has been undertaken.