替代PBPB二极体的理论研究:结构分析,四极根性质和激发状态
Franziska Bell1, David Casanova, Martin Head-Gordon
1Department of Chemistry, University of California, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Journal of the American Chemical Society
|August 12, 2010
概括
这项研究评估了1,3-diborata-2,4-diphosphoniocyclobutane-1,3-diyl双替代的和甲基的基化性质. 温和的激进特征解释了"四级激进"的稳定性,替代效应也发挥了关键作用.
科学领域:
- 计算化学计算化学
- 有机化学 有机化学
- 量子化学 是一个量子化学.
背景情况:
- 1,3-二博-2,4-二二氧环丁-1,3-二二次替代具有独特的电子特性.
- 系统的稳定性是指
- 帕拉四根基的基本原理
- 异构体一直是人们感兴趣的对象.
研究的目的:
- 为了研究1,3-diborata-2,4-diphosphoniocyclobutane-1,3-diyl双替代的和甲基异构体的化物性质.
- 为了合理化帕拉异构体的稳定性,并了解PBPBB单元之间的电子通信.
主要方法:
- 使用完美配对 (PP),完整活动空间SCF (CASSCF) 和受限制活动空间双旋转翻转 (RAS-2SF) 方法进行电子结构计算.
- 分析轨道占用数,移位能量,低兴奋状态和磁合常数.
主要成果:
- 轨道占用数表明不到一个未配对的电子,这表明它具有中等激进的特征.
- 在单个PBPB单元之间发现了弱相互作用,三重单元之间的通信是可以忽略不计的.
- 与甲基同位素相比,pi框架在准同位素中促进了更大的通信,占能量差异的三分之一.
结论:
- "四原基"的稳定性归因于其中等激进的特征.
- 庞大的替代品的立体和电子效应显著影响电子性能.
- 虽然pi系统通信有助于异构体特定的行为,但替代效应也至关重要.
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