Controlled polymerization of DL-lactide and ε-caprolactone by structurally well-defined alkoxo-bridged di- and triyttrium(III) complexes
Controlled polymerization of DL-lactide and ε-caprolactone by structurally well-defined alkoxo-bridged di- and triyttrium(III) complexes
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DOI：
10.1021/ma0000834
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发表时间：
2000-05-30
期刊：
影响因子：
5.5
通讯作者：
Tolman, WB
中科院分区：
文献类型：
--
作者：
Chamberlain, BM;Jazdzewski, BA;Tolman, WB
我们制备了钇(III)醇盐[(L-Me2)(HLMe2)Y-3(OCH2C6H5)(4)](3)和[(S-L-Me)Y](2)。 2(HOCH2C6H5) (1. 2BnOH) 通过用苯甲醇处理两种先前开发的络合物。配合物 3 具有新颖的簇结构，似乎保留在溶液中，并且能够聚合 DL-丙交酯 (LA) 和ε-己内酯 (CL)。分子量与转化图和[M]/[3]比率的线性性质证明了聚合反应是受控制的。使用 3 进行 LA 聚合的动力学相对于低 [LA]I[Y] 比例下的单体而言是一级动力学。 CL在单体中的聚合是零级的。配合物 1 2BnOH 具有以前在固体和溶液状态下观察到的二聚结构。然而，1 中添加了苯甲醇部分。 2BnOH 提高了 LA 聚合的速率，并允许控制分离的聚丙交酯的分子量，这是早期报道的二聚体中未见的功能。复杂 1 。 2BnOH 对于 CL 的聚合没有活性。
We have prepared the yttrium(III) alkoxides [(L-Me2)(HLMe2)Y-3(OCH2C6H5)(4)] (3) and [(S-L-Me)Y](2). 2(HOCH2C6H5) (1 . 2BnOH) through treatment of two previously developed complexes with benzyl alcohol. Complex 3 possesses a novel cluster structure that appears to be retained in solution and is capable of polymerizing both DL-lactide (LA) and epsilon-caprolactone (CL). The polymerizations are controlled as evidenced by the linear nature of molecular weight versus conversion plots and [M]/[3] ratios. The kinetics of LA polymerization using 3 are first-order with respect to the monomer at low [LA]I[Y] ratios. The polymerization of CL is zero-order in monomer. Complex 1 2BnOH possesses a dimeric structure previously seen in both the solid and solution state. However, the added presence of benzyl alcohol moieties in 1 . 2BnOH increases the rate of LA polymerization and allows for control over the molecular weights of isolated polylactide, a feature unseen in earlier reported dimers. The complex 1 . 2BnOH is not active for the polymerization of CL.