Dialkyllanthanide Complexes Containing New Tridentate Monoanionic Ligands with Nitrogen Donors
Dialkyllanthanide Complexes Containing New Tridentate Monoanionic Ligands with Nitrogen Donors
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DOI：
10.1021/om7010936
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发表时间：
2008-01
期刊：
影响因子：
2.8
通讯作者：
Xin Xu;Xiaoyan Xu;Yao-Quan Chen;Jie Sun
中科院分区：
文献类型：
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作者：
Xin Xu;Xiaoyan Xu;Yao-Quan Chen;Jie Sun
合成了3个新的三齿NNN配体前体CH3C(2，6-(IPR)2C6H3NH)CHC(CH3)(NCH2CH2−D)(D=NMe2，NET2，N((CH2CH2)2CH2))。随后与原位生成的Ln(CH2SiMe3)3(THF)n(Ln=Nd，Sm，Y，Lu)进行金属化反应，得到了6个无溶剂的二烷基稀土配合物。用单晶X-射线衍射法对其中5个稀土配合物进行了表征，结果表明，悬臂D在固态下与稀土离子成键。这些配合物在C6D6中的核磁共振谱表明，这种配位在溶液中保持不变。这些二烷基稀土配合物对ϵ-己内酯的开环聚合表现出很高的活性，生成了窄多分散聚合物。悬臂的大小对所得聚合物的相对分子质量有显著影响。与含有−NMe2基团的Y络合物相比，含有−NET2和−N((CH2CH2)2CH2)基团的Y络合物得到的聚合物相对分子质量要高得多(60000比20000)。
Three new tridentate NNN ligand precursors, CH3C(2,6-(iPr)2C6H3NH)CHC(CH3)(NCH2CH2−D) (D = NMe2, NEt2, N((CH2CH2)2CH2)), were synthesized. Subsequent metalations with in situ generated Ln(CH2SiMe3)3(THF)n (Ln = Nd, Sm, Y, Lu) provided six solvent-free dialkyllanthanide complexes. Five of the lanthanide complexes were characterized by single-crystal X-ray diffraction, which showed that the pendant arm D bonds to the lanthanide ion in the solid state. The NMR spectra of these complexes in C6D6 showed that such coordination is retained in solution. These dialkyllanthanide complexes show high activities for the ring-opening polymerization of ϵ-caprolactone, in which narrow-polydispersity polymers were produced. The size of the pendant arm has a significant effect on the molecular weight of the polymer obtained. In comparison to the Y complex with a −NMe2 group, the Y complexes with −NEt2 and −N((CH2CH2)2CH2) groups yield much higher molecular weight polymer (60 000 vs 20 000).