Synthesis,Structure And Catalytic Activity For Isoprene Polymerization Of Rare-earth Metal Alkyl Complexes Supported By Functionalized 3-(2-tert-butylanilinomethylene) Indolyl Ligands

All experiments were carried out under the dry and oxygen-free argon atmosphere.Reactions of [3-?2-tBuC₆H₄N=CH?C₈H₅NH]?1?with 1equiv of RE?CH₂SiMe₃?₃?thf?₂?RE = Y,Er,Dy?in toluene,gave rare-earth alkyl complexes{[?-?²:?¹:?¹-3-[2-^tBuC₆H₄NCHCH₂Si?CH₃?₃]C₈H₅N]RE[CH₂Si?CH₃?₃]?thf?}2?RE = Y,Er,Dy?.In the process,the imino C=N group was transferred to the amido group by alkyl CH₂SiMe3 insertion.When [3-?2-t BuC₆H₄N=CH?C₈H₅NH]?1?was reduced to[3-?2-tBuC₆H₄NHCH₂?C₈H₅NH]?2?,the reactions of[3-?2-tBuC₆H₄NHCH₂?C₈H₅NH]?2?with RE?CH₂SiMe₃?₃?THF?₂?RE =Yb,Y,Er,Dy?in toluene,obtained the rare earth complexes of functionalized indole {[?-?²:?¹:?¹-3-[2-^tBuC₆H₄NCH₂]C₈H₅N]Yb[CH₂Si?CH₃?₃]?thf?}2?RE = Yb,Y,Er,Dy?.All the complexes were characterized by elemental analyses,IR spectra and X-ray diffraction.The experimental results showed that the complexes could initiate the polymerization of isoprene with a high activity to afford polyisoprenewith high regioselectivity in the presence of cocatalysts.Results also showed that the activity and selectivity were significantlydependent on the solvent,temperature and aluminum alkyl.