Zinc Complexes Containing Coumarin-Derived Anilido-Aldimine Ligands as Catalysts for Ring Opening Polymerization of l-Lactide

The coumarin-derived ligand precursors L(1)H–L(6)H have been prepared. Treatment of these ligand precursors with 1.2 equiv. of ZnEt(2) in toluene affords zinc ethyl complexes (LZnEt) 1–6 (where L = coumarin-derived ligands bearing different functional groups). Reaction of ligand precursor L(3)H with 1.5 equiv. of Zn[N(SiMe(3))(2)](2) in toluene affords the zinc amide complex, L(3)ZnN(SiMe(3))(2), 7. All these compounds were characterized by NMR spectroscopy and elemental analysis. The molecular structures are reported for 1 and 7. The catalytic activities of complexes 1–7 towards the ring opening polymerization of l-lactide in the presence of 9-AnOH have been investigated.