Facile Synthesis of Hydroxyl-Ended, Highly Stereoregular, Star-Shaped Poly(lactide) from Immortal ROP of rac-Lactide and Kinetics Study
Facile Synthesis of Hydroxyl-Ended, Highly Stereoregular, Star-Shaped Poly(lactide) from Immortal ROP of rac-Lactide and Kinetics Study
复制标题
从外消旋丙交酯的不朽 ROP 中轻松合成羟基末端、高度立构、星形聚丙交酯并进行动力学研究
DOI：
10.1021/ma101202g
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发表时间：
2010-07
期刊：
影响因子：
5.5
通讯作者：
Chen, Xuesi
中科院分区：
文献类型：
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作者：
Zhao, Wei;Cui, Dongmei;Liu, Xinli;Chen, Xuesi
三乙醇胺（TEA）与3当量的含O，N，N，O-四齿Salan配体的钇烷基配合物1反应，通过复分解反应得到三核钇醇盐配合物2。配合物2在温和条件下以活性方式引发丙交酯开环聚合。值得注意的是，2是如此宽容的质子TEA，在各种TEA钇的摩尔比范围从1：3到81：1，聚合进行顺利，这表明一个不朽的特性。所得聚乳酸具有可变的分子量（Mn = 1.36 × 104至32.54 × 104），但分子量分布窄（PDI = 1.02 - 1.09），特别是纯杂立构的（Pr = 0.99），羟基官能化和星形结构，通过NMR光谱和MALDI-TOF质谱分析对其进行了充分表征，并通过计算收缩因子值g′（g′ = 0.96）通过Mark-Houwink方程。对“不朽”聚合的详细考察给出了独特的解释。
Triethanolamine (TEA) reacted with 3 equiv of yttrium alkyl complex 1 bearing O,N,N,O-tetradentate Salan ligand to give a trinuclear yttrium alkoxide counterpart 2 via metathesis reaction. Complex 2 initiated the ring-opening polymerization of rac-lactide in a livingness mode under mild conditions. Remarkably, 2 was so tolerant of the protic TEA that under various TEA-to-yttrium molar ratios ranging from 1:3 up to 81:1, the polymerization performed smoothly, suggesting an immortal characteristic. The resultant polylactides had variable molecular weights (Mn = 1.36 × 104to 32.54 × 104) but narrow molecular weight distributions (PDI = 1.02−1.09), and, especially, pure heterotactic (Pr = 0.99), hydroxyl-functionalized and star-shaped architecture, which were fully characterized by NMR spectroscopy and MALDI−TOF mass spectrum analyses and confirmed further by calculating the contraction factor value g′ (g′ = 0.96) via Mark−Houwink equations. Detailed investigation of the “immortal” polymerization gave a uniqu...