循环-基催化剂用于环膨胀转化解聚合的聚合
Andrew J Boydston1, Yan Xia, Julia A Kornfield
1Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
Journal of the American Chemical Society
|August 30, 2008
概括
研究人员开发了用于环膨胀元解聚合 (REMP) 的循环催化剂. 较短的带改善了催化剂的释放,而和合物则提高了聚合率,产生了高度活性和稳定的催化剂.
科学领域:
- 有机金属化学 有机金属化学
- 聚合物科学 聚合物科学
- 催化剂是一种催化剂.
背景情况:
- 环扩张元解聚合 (REMP) 对于合成循环多聚烯至关重要.
- 开发高效和稳定的催化剂是推动REMP的关键.
- 在 (Ru) 中心上的N-异环碳 (NHC) 连接体对转化催化有前景.
研究的目的:
- 合成和评估用于REMP的新型循环Ru-alkylidene催化剂.
- 为了研究带长度和NHC连接体电子对催化剂性能的影响.
- 为了优化催化剂设计,以高效地聚合循环甲.
主要方法:
- 模块循环Ru-alkylidene复合物的合成,具有不同的长和NHC连接体.
- 使用NMR光谱和单晶X射线衍射进行结构性表征.
- 评估在环烯聚合过程中的催化活性,测量传播速率,链转移和稳定性.
主要成果:
- 增加长度提高了聚合率,但降低了催化剂的稳定性.
- 较短的 (5或6碳) 促进了分子内链转移和催化剂释放.
- 对NHC连接体的电子修饰 (脊柱和) 显著增加了聚合率.
- 开发出来的催化剂在REMP中是稳定且高度活跃的.
结论:
- 触媒设计涉及带长度和NHC连接物和度对于高效的REMP至关重要.
- 优化的循环Ru催化剂为循环聚烯提供了一个有前途的途径.
- 模块化方法允许微调特定应用的催化剂性能.
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