在中性和阳离子Pd (II) 复合体中的甲基键中插入烯
Laurent F Groux1, Thomas Weiss, Dastigiri N Reddy
1Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4.
Journal of the American Chemical Society
|February 11, 2005
概括
这项研究详细介绍了(II) 甲基化合物如何通过2,1插入Pd-Me键与烯 (AN) 发生反应,形成二聚体和三聚体. 负电荷的配体加快了这一关键的协调聚合反应.
科学领域:
- 有机金属化学 有机金属化学
- 聚合化学 聚合化学 聚合化学
- 催化剂是一种催化剂.
背景情况:
- (II) 复合物是有机合成和聚合过程中的关键催化剂.
- 将像烯酸这样的极性单体纳入聚烯酸是具有挑战性的,但有价值的.
- 了解插入机制对于催化剂设计和过程优化至关重要.
研究的目的:
- 研究Pd(II) 甲基化合物与烯酸的反应机制.
- 阐明联体电荷在插入动力学中的作用.
- 为极性烯的协调聚合提供机理性见解.
主要方法:
- 合成Pd(II) 甲基化合物与重的氧亚或氧胺联体.
- 通过低温1H NMR光谱学监测的烯 (AN) 的反应研究.
- 在伪第一阶条件下进行动力分析,以确定速率常数和激活参数.
主要成果:
- Pd(II) 甲基化合物经历了2,1插入AN到Pd-Me键,形成二次体/三次体与桥接的α-基团.
- 最初的N结合的AN同质化为一个pi结合的物种,随后是快速插入.
- 与中性或阴性类似物相比,带有负电荷联体的复合物呈现出明显更快的AN插入率.
结论:
- 通过增加复合体上的负电荷来提高AN插入的速度.
- 连接体电子特性在Pd(II) 甲基化合物对极性烯酸的反应性中起着关键作用.
- 这些发现为在协调聚合过程中结合极性共纳体提供了基本的机制理解.
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