Bis(aniline-phenolate) complexes of group 4 metals: Coordination chemistry and lactide polymerization catalysis

The substituted aniline-phenol ligand binds in the reduced-monoanionic form to the group 4 metals giving fluxional octahedral [(NO)(2)M(OR)(2)]-type complexes. The X-ray structures of the Zr- and Hf-complexes revealed cis-N/trans-O binding and an overall C(1) symmetry. All three complexes exhibited high activities in polymerization of L-lactide and rac-lactide. The Zr- and Hf-complexes led to heterotactically enriched PLA. (C) 2011 Elsevier B.V. All rights reserved.