Unprecedented 3,4-Isoprene and cis-1,4-Butadiene Copolymers with Controlled Sequence Distribution by Single Yttrium Cationic Species

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• 作者：Bo Liu ; Xingbao Wang ; Yupeng Pan ; Fei Lin ; Chunji Wu ; Jingping Qu ; Yi Luo ; Dongmei Cui
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：December 23, 2014
• 年：2014
• 卷：47
• 期：24
• 页码：8524-8530
• 全文大小：330K
• ISSN：1520-5835

文摘

Precisely controlling the stereochemistry of a copolymerization by single catalyst, and achieving copolymers with predicted sequences, is a challenging project in organometallic and macromolecular sciences. This article reports that the copolymerization of isoprene and butadiene with the 3,4- and cis-1,4 different regioselectivities has been accessed through employing a pyridylmethylene functionalized fluorenyl ligated yttrium cationic species. The thus unprecedented regularity combination is attributed mainly to the backbiting interaction of the penultimate unit of the polymer chain to the active central metal ion according to the DFT calculation. Moreover, the compositions can be adjusted by regulating the monomer feed ratio according to the copolymerization kinetics study.