在Pd催化与一氧化碳交替共聚化中,主要是1,2-插入 styrene
K Nozaki1, H Komaki, Y Kawashima
1Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501 Japan.
Journal of the American Chemical Society
|July 18, 2001
概括
这项研究揭示了与其他配体形成对比的,在催化与CO的共聚合中,烯的1,2-插入是独有的. 这种区域选择性防止β-化物消除,使得可控的聚合物链生长.
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:
- styrene 插入到 acyl-palladium 键中的区域选择性对于与一氧化碳 (CO) 的催化共聚变至关重要.
- 传统的联体往往导致主导的2,1插入,这可能导致链终结通过β-化物消除.
研究的目的:
- 通过使用Palladium-BINAPHOS复合物,研究在固体测量和聚合反应中的 styrene 插入的区域选择性.
- 阐明区域选择性在 styrene-CO 共聚合机制中的作用及其对聚合物链生长的影响.
主要方法:
- 核磁共振 (NMR) 谱学被用来研究在石化反应中的区域选择性.
- 一个聚合物附着的复合物被合成,以模仿现实的聚合条件.
- 矩阵辅助激光脱/电离飞行时间 (MALDI-TOF) 质量分析用于共聚物链末端分析.
主要成果:
- 固体测量反应产生了1,2-和2,1-烯插入产物.
- 在聚合条件下,聚合物附着的复合物完全产生了1,2-插入产品.
- 从2,1-复合体观察到β-化物消除,导致终止,但不是从1,2-复合体.
结论:
- 独特的1,2-插入 styrene 是由-BINAPHOS 系统介导的成功的 styrene-CO 共聚合的原因.
- 这种独特的区域选择性防止了链条过早终结,允许控制的聚合物形成.
- 这些发现与使用常规联体的系统形成鲜明对比,突显了联体设计在催化中的重要性.
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