Organolanthanide-Initiated Living Polymerizations of ε-Caprolactone, δ-Valerolactone, and β-Propiolactone
Organolanthanide-Initiated Living Polymerizations of ε-Caprolactone, δ-Valerolactone, and β-Propiolactone
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DOI：
10.1021/ma951400n
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发表时间：
1996-02
期刊：
影响因子：
5.5
通讯作者：
M. Yamashita;Yasunori Takemoto;E. Ihara;H. Yasuda
中科院分区：
文献类型：
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作者：
M. Yamashita;Yasunori Takemoto;E. Ihara;H. Yasuda
稀土金属有机配合物SmMe（C5 Me 5）2（THF）和[SmH（C5 M5）2]2可引发ε-己内酯和δ-戊内酯的活性聚合，得到分子量分布极窄（Mw/Mn < 1.08）的高分子量聚酯（Mn > 70000），而这些引发剂对β-丙内酯的聚合完全呈惰性。与镧系烷基络合物相比，镧系醇盐如SmOEt（C5 Me 5）2（OEt 2）、[YOMe（C5 H5）2]2和YOMe（C5 Me 5）2（THF）对β-丙内酯、δ-戊内酯和ε-己内酯的聚合显示出相当好的催化活性。本文从稀土金属有机化合物与内酯的等摩尔反应出发，讨论了LnMe（C5 Me 5）2（THF）（Ln = Sm，Yb）或LnOR（C5 R '5）2（Ln = Sm，Y）引发内酯聚合的引发机理。
Organolanthanide complexes such as SmMe(C5Me5)2(THF) and [SmH(C5M5)2]2 initiate the living polymerizations of e-caprolactone and δ-valerolactone to give high molecular weight polyesters (Mn > 70 000) with extremely narrow molecular weight distributions, Mw/Mn < 1.08, while these initiators are completely inert for the polymerization of β-propiolactone. In contrast to lanthanide alkyl complexes, lanthanide alkoxides such as SmOEt(C5Me5)2(OEt2), [YOMe(C5H5)2]2, and YOMe(C5Me5)2(THF) exhibit fairly good catalytic activity for polymerizations of β-propiolactone, δ-valerolactone, and e-caprolactone. The initiation mechanisms for the polymerization of lactones by LnMe(C5Me5)2(THF) (Ln = Sm, Yb) or LnOR(C5R‘5)2 (Ln = Sm, Y) initiators are discussed on the basis of equimolar reactions between organolanthanides and lactones.