Synthesis and characterization of N-aryloxo-functionalized β-ketoiminate rare-earth complexes and their catalytic activity for the polymerization of ε-caprolactone

The synthesis and characterization of dimeric rareearth amides stabilized by a dianionic N-aryloxo functionalized β-ketoiminate ligand are described.Reactions of 4-(2-hydroxy-5-methyl-phenyl) imino-2-pentanone(LH2) with Ln[N(SiMe3)2]3(μ-Cl)Li(THF)3 in a 1:1 molar ratio in THF gave the dimeric rare-earth amido complexes [LLn{N(SiMe3)2}(THF)]2 [Ln = Nd(1),Sm(2),Yb(3),Y(4)].These complexes were well characterized,and the definitive molecular structures of complexes 3 and 4 were determined.It was found that complexes 1― 4 can initiate the ring-opening polymerization of ε-caprolactone,and the ionic radii of the central metals have significant effect on the catalytic activity.

The synthesis and characterization of dimeric rare-earth amides stabilized by a dianionic N-aryloxo functionalized ,8-ketoiminate ligand are described. Reactions of 4-（2-hydroxy-5-methyl-phenyl） imino-2-pentanone （LH2） with Ln[N（SiMe3）2]3（μ-Cl）Li（THF）3 in a 1：1 molar ratio in THF gave the dimeric rare-earth amido complexes [LLn{N（SiMe3）2}（THF）]2 [Ln = Nd （1）, Sm （2）, Yb （3）, Y （4）]. These complexes were well characterized, and the definitive molecular structures of complexes 3 and 4 were determined. It was found that complexes 1-4 can initiate the ring-opening polymerization of ε-caprolactone, and the ionic radii of the central metals have significant effect on the catalytic activity.