Homolysis Of The Ln-N Bond. Synthesis, Characterization And Catalytic Activity Of Lanthanide (â…¡) Complexes With 3-Picolyl-Functionalized Indenyl Ligands

All experiments were carried out under a dry and oxygen-free argon atmosphere by using standard Schlenk techniques. Reaction of 3- (C1CH2)C5H4N?HCl with 2 equiv of C9H7Li in THF at 0℃ yielded 3-(3- C5H4NCH2)C9H7(1)in 69% yield ,1 reacted with 1 equiv. of n-BuLi yielded 3-(3-C5H4NCH2)C9H6Li . Interaction of 3-(3-C5H4NCH2)C9H6Li with excess Me3SiCl yielded 1-SiMe3-3-(3-C5H4NCH2)C9H6 (2) in 87% yield. Interactions of [(Me3Si)2N]3Ln(μ-Cl)Li(THF)3(Ln = Yb, Eu, Sm) with 2 equiv. of compound 1 in toluene gave [η5:η1-3-(3-C5H4NCH2) C9H6]2Yb (3), [η5:η1-3-(3-C5H4NCH2)C9H6]2Eu (4) and [η5:η1-3-(3-C5H4NCH2) C9H6] 2Sm (5). The similar reactions of [(Me3Si)2N]3Ln (μ-Cl)Li(THF)3(Ln = Yb, Eu, Sm ) with 2 equiv. of compound 2 in reflux toluene, yielded the corresponding organolanthanide(Ⅱ) complexes [η5:η1-1-SiMe3-3-(3- C5H4NCH2)C9H5]2Yb (6) , [η5:η1-1-SiMe3-3-(3-C5H4NCH2)C9H5]2Eu (7) and [η5:η1-1-SiMe3-3-(3-C5H4NCH2)C9H5]2Sm (8) . All the complexes were characterized by IR , 1H-NMR , 13C-NMR and Elemental Analysis. On the basis of the above experimental results, we found that these experiments further certify the heteroatom coordination promoted homolytic reaction of the Ln-N bond. This work demonstrates that the methodology for preparation of organolanthanide(II) complexes by homolysis of the Ln-N bond can be extended to 3-Picolyl functionalized Indenyl Ligands.At the same time, the organolanthanide(II) complexes function as single- component MMA polymerization catalysts were studied. The results showed that all the complexes behave good catalytic activeity in catalyzing MMA polymerization in solvents THF and DME. It found that temperatures, inonic radius and solvents have influenes on activities of catalysts. Studies also showed that high transformation could be achieved by selecting catalysts, solvents and temperature. These catalysts may have potential industrial applications.