Synthesis, Characterization And Catalytic Activity Of Organolanthanide Complexes With Me₂Si-Bridged Substituted Indenyl Ligands

All experiments were carried out under the dry and oxygen-free argon atmosphere by using standard Schlenk techniques.Reaction of C₄H₇OCH₂OTs with 1 equiv of C₉H₇Li in THF at 0℃yielded C₄H₇OCH₂C₉H₇(1)in 83%yield. Treatment of(1)with 1 equiv of n-BuLi in Et₂O at -78℃,followed by reaction with 0.5 equiv of Me₂SiCl₂ yielded(C₄H₇OCH₂C₉H₆)₂SiMe₂(2)in 34% yield.Treatment of[(Me₃Si)₂N]₃Yb^â…¢(μ-Cl)Li(THF)₃ and[(Me₃Si)₂N]₃Eu^â…¢(μ-Cl)Li(THF)₃ with 1 equiv of(2)in refluxing toluene,gave the bivalent complexes[η⁵;η¹-(C₄H₇OCH₂C₉H₅)₂SiMe₂]Yb^â…¡(3)in 67%yield,[η⁵;η¹-(C₄H₇O CH₂C₉H₅)₂SiMe₂]Eu^â…¡(4)in 54%yield.Reaction of[(Me₃Si)₂N]₃Sm^â…¢(μ-Cl)Li(THF)₃,[(Me₃Si)₂N]₃Nd^â…¢(μ-Cl)Li (THF)and[(Me₃Si)₂N]₃Y^â…¢(μ-Cl)Li(THF)₃ with 1 equiv of(2)in refluxing toluene,gave the three tervalent complexes[η⁵;η¹-(C₄H₇OCH₂C₉H₅)₂SiMe₂] Sm^â…¢Cl(C₆H₁₄)(5)in 44%yield,[η⁵;η¹-(C₄H₇OCH₂C₉H₅)₂SiMe₂]Nd^â…¢Cl(C₆H₁₄) (6)in 41%yieldå’Œ[η⁵;η¹-(C₄H₇OCH₂C₉H₅)₂SiMe₂]Y^â…¢Cl(1/2C₆H₁₄)(7)in 46% yield.All the complexes were fully characterized by elemental and spectroscopic analyses.The activities of lanthanide complexes as single-component catalysts in catalyzing MMA andε-CL polymerization were examined.It was found that the activities of the catalysts,stereo-regularity of PMMA,and the molecular weight of polymers were dependent on the solvents,temperature and the central metal of the catalysts.