Magnesium complexes containing bis-amido-oxazolinate ligands as efficient catalysts for ring opening polymerisation of l-lactide

Abstract

A series of magnesium bis(amido-oxazolinate) complexes have been described. Reactions of six amido-oxazolinate ligand precursors, HNC₂^MeOxa, HNC₂^OMeOxa, HNC₂^StBuOxa, HNPhOxa, HNPh^OMeOxa or HNPh^SMeOxa, with half molar equivalent of MgⁿBu₂ in hexane yield the magnesium bis(amido-oxazolinate) complexes, (NC₂^EOxa)₂Mg [C₂^E = propyl, (NC₂^MeOxa)₂Mg (1); C₂^E = 2-methoxyethyl, (NC₂^OMeOxa)₂Mg (2); C₂^E = 2-tert-butylthioethyl, (NC₂^StBuOxa)₂Mg (3)], or magnesium bis(anilido-oxazolinate) complexes, (NArOxa)₂Mg [Ar = phenyl, (NPhOxa)₂Mg (4); Ar = 2-methoxyphenyl, (NPh^OMeOxa)₂Mg (5); Ar = 2-methylthiophenyl, (NPh^SMeOxa)₂Mg (6)], respectively. The molecular structures are reported for compounds 1, 2, 5 and 6. Their catalytic activities toward the ring opening polymerisation of L-lactide in the presence of benzyl alcohol are also under investigation.