碳化合物的Rh介导聚合:机制和立体调节
Erica Jellema1, Peter H M Budzelaar, Joost N H Reek
1Department of Homogeneous and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV, Amsterdam.
Journal of the American Chemical Society
|August 25, 2007
概括
在催化聚合时,可产生近乎有生命特征的聚合物. 该研究阐明了催化机制,将N(2) 消除确定为限制速度的步骤,并提出了协同作用的立体化学.
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:
- 醇聚合是功能性聚合物的关键途径.
- 了解催化机制对于控制聚合物特性至关重要.
- 催化剂对于二醇聚合是有效的,但机制需要进一步阐明.
研究的目的:
- 为了阐明催化型二醇聚合物的机制.
- 研究催化剂结构对活性和聚合物性质的作用.
- 确定聚合物的立体化学和控制机制.
主要方法:
- 催化剂前体 (二烯) 中的联体变异Rh(I) ((N,O).
- 聚合过程的动力学研究.
- 计算研究 (密度函数理论) 来建模反应路径.
- 核磁共振 (NMR) 谱学用于聚合物表征.
主要成果:
- 催化剂活性对N,O-捐赠体连接体敏感,但聚合物分子重量不是.
- 烯配体显著影响聚合物结构,在催化过程中保持结合.
- 聚合物表现出接近生命的特征,终结缓慢,没有观察到链转移.
- 计算研究支持一个碳基机制,以N(2) 消除为速度限制的步骤.
- 聚合物暂时被赋予一个协同作用的立体化学.
结论:
- 在形成活性罗物种时,N,O-捐赠体连接物很可能会丢失.
- 烯配体在聚合过程中起着至关重要的作用.
- 聚合过程通过碳中间体进行,而N(2) 消除速度是限制性的.
- 在N(2) 淘汰或迁移插入过程中,综合特异性可能由链末效应控制.
相关概念视频
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