Well-defined aminophenolate zinc and magnesium complexes as excellent inhitiators for the ROP of lactides

摘要

A series of molecular homo and heteroleptic zinc and magnesium compounds with aminophenolate ligands [(μ,η~2-L~2)ZnEt] _2 (1), [(η~2-L~2)Zn(μ-BnO)]_2 (2), [Zn(η~2-L~2)_2] (3), [Zn(η ~2-L~3)_2] (4), [Mg(η~2-L ~3)_2] (5) (L~2-H = N-[methylene(2-hydroxy-3,5-di- tert-butylphenyl)]-N-methyl-N-cyclohexylamine, L~3-H = N-[methylene(2-hydroxy-3,5-di-tert-butylphenyl)]-N-methyl-N-methyl-1, 3-dioxolaneamine) have been prepared and characterized. The homoleptic complexes 3-5 are most probably a mixture of diastereoisomers that in solution show an interesting dynamics which plays an important role in their catalytic behavior. The complexes 2-5 are efficient initiators in ring-opening polymerization (ROP) of lactides to produce polymers with desired molecular weight and narrow polydispersity.