Synthesis, Characterization And Catalytic Activity Of Divalent Lanthanide Complexes With Tetrahydro-2H-pyranyl-Functionalized Indenyl Ligands

All experiments were performed under an atmosphere of dry argon with the rigid exclusion of air and moisture using standard Schlenk techniques. Reaction of C5H9OCH2Cl with 1 equiv of C9H7Li in THF yielded C5H9OCH2C9H7 (1) in 73% yield. Treatment of 1 with 1 equiv of n-BuLi, followed by reaction with 2 equiv of Me3SiCl in THF yielded C5H9OCH2C9H6SiMe3 (2) in 96% yield.Treatment of [(Me3Si)2N]3YbIII(μ-Cl)Li(THF)3 with 2 equiv of 1,2 in toluene at 80°C via a homolytic reaction, gave the ytterbium(II) complexes [η5:η1-(C5H9OCH2C9H6)]2YbII (3) in 76% yield, [η5:η1-(C5H9OCH2C9H5 SiMe3)]2YbII(4) in 67% yield. Treatment of [(Me3Si)2N]3EuIII(μ-Cl)Li (THF)3 with 2 equiv of 1 and 2 in toluene at 60°C via a homolytic reaction, gave the europium(II) complexes [η5:η1-(C5H9OCH2C9H6)]2EuII(5) in 65% yield, [η5:η1-(C5H9OCH2 C9H5SiMe3)]2EuII(6) in 41% yield. Recrystallization of 6 from hexane gave the europium(II) complexe [η5:η1-(C5H9OCH2C9H5SiMe3)]2 EuII·1/2C6H14 (7). All the compounds were fully characterized by spectroscopic methods and elemental analyses. Complexes 4 and 7 were additionally characterized by a single-crystal X-ray diffraction study. These results further certify the heteroatom coordination promoted homolytic reaction of the Ln-N(Ln = Yb,Eu) bond. This work further extends the new methodology to prepare organolanthanide (II) complexes.At the same time, We have studied the catalytic activity of the organolanthanide(II) complexes as single-component polymerization catalysts of Methyl methacrylate andε-caprolactone. Studies showed that 3 and 5 have no catalytic activity in catalyzing polymerization, but 4 and 6 have catalytic...