Zinc complexes supported by N,O-bidentate amino-alkoxyl ligands: synthesis, characterization and catalytic property for the ring-opening polymerization of L-lactide

A series of new zinc complexes based on the amino-alkoxyl ligands [1-HOC(R 1 R 2 )-2-NMe 2 C 6 H 4 [R 1 = H, R 2 = Ph ( L 1 H), R 1 = Et, R 2 = Ph ( L 2 H), R 1 = H, R 2 = 2-FPh ( L 3 H), R 1 = H, R 2 = 2-BrPh ( L 4 H)] were synthesized. The zinc complexes were characterized by NMR spectroscopy and elemental analysis, as well as by an X-ray diffraction study. The solid-state structures of 2 and 3 reveal that the Zn centers adopt four-coordinated distorted tetrahedral geometries. These complexes show high activities in the ring-opening polymerization of L-lactide in the presence of benzyl alcohol in a living fashion. Complex 3 (R 1 = H, R 2 = 2-FPh) shows the highest activity among complexes 1 - 4 .