在一个被替代的 [8]annulene 离子基中进行道化和固体诱导的环形化
Cheryl D Stevenson1, Lance J Heinle, John P Davis
1Department of Chemistry, Illinois State University, Normal, IL 61790-4160, USA.
Journal of the American Chemical Society
|March 14, 2002
概括
在 tert-butoxy-cyclooctatetraene 离子激素中的固体相互作用会导致环,减少 EPR 合常量. 化减小了这种效应,增加了合常数,并暗示了可能由于量子道化而发生的快速形状变化.
科学领域:
- 有机化学 有机化学
- 物理化学 物理化学
- 频谱学是一种光谱学.
背景情况:
- 循环八甲烯 (COT) 是一个非平面的八个环的环系.
- 替代COT的阳离子基具有独特的电子和结构性质.
- 电子磁共振 (EPR) 光谱是研究激进物种的强大工具.
研究的目的:
- 调查三丁替代物的结构和电子效应,以其离子基的形式对循环甲烯环系统进行研究.
- 了解固态相互作用对COT环平面性的影响.
- 探索同位素替代 (脱) 对EPR合常数和构造动态的影响.
主要方法:
- 电子偏磁共振 (EPR) 光谱学被用来研究三丁-环氧三丁 (tert-butoxy-COT) 和其化模拟物 (tert-butyl-d(9) -COT).
- 对EPR合常数的分析提供了对COT部分电子结构和几何学的见解.
- 计算方法被隐含地用于解释观察到的光谱数据和结构动态.
主要成果:
- tert-butoxy 组与 COT 环之间的固体相互作用会导致离子基中八个成员环的显著破裂.
- 这种非平面性导致了EPR合常数的显著减弱.
- 在三乙组 (三乙-d) 中用取代减少了固态阻碍,从而产生了更大的可测量的电子质子合常量.
- 在COT部分的D(2d) 符合者之间的振荡非常快 (k > 10(12) s(-1)).
结论:
- 绝缘效应在确定 tert-butoxy-COT 离子基的构造方面发挥着至关重要的作用.
- 同位素替代提供了一种敏感的方法来探测构造动态和固态影响.
- 观察到的快速形状变化表明量子力学道在环动力学中的参与.
相关概念视频
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