富含电子的三中心结合:s,p相互作用在p块中的作用
Markéta L Munzarová1, Roald Hoffmann
1Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, 14853-1301, USA.
Journal of the American Chemical Society
|April 25, 2002
概括
s,p 混合对于理解阳离子中富含电子的三中心结合至关重要. 这种效应使轨道变得不稳定,周期表中的稳定性下降,在组内变化.
科学领域:
- 计算化学的计算化学
- 量子化学 是一个量子化学.
- 化学结合理论 化学结合理论
背景情况:
- 朗德尔-皮门特尔模型为富含电子的三中心结合提供了一个基本框架.
- 结合s,p混合提供了对这些结合系统的更细致的理解.
- 定期趋势和特定群体的行为需要详细的调查.
研究的目的:
- 分析s,p混合在富含电子的三中心结合中的意义.
- 调查这些债券安排的稳定性中的周期和集团趋势.
- 阐明 s,p 混合在三原子离子电子结构中的作用.
主要方法:
- 对三原子22价值电子离子进行了详细的量子化学计算.
- 扰乱分子轨道 (MO) 分析被用来解释s,p混合效应.
- 密度函数计算验证了各种线性三化物,三化物和三化物的MO分析.
主要成果:
- s,p混合使3sigma(g) 轨道不稳定,受中心s和终端p轨道重叠的影响.
- 来自p(pi) 单一对的排斥进一步破坏了结合的稳定,随着负电荷的增加.
- 在周期表中,异电子X(3) 系统的稳定性从右向左下降.
结论:
- s,p混合对于准确描述富含电子的三中心结合是必不可少的,修改最简单的模型.
- 周期性趋势显示稳定性随着负电荷的增加和特定群体行为的增加而下降,例如,tripnictides中的超价性.
- 强烈的s,p混合可以逆转分子轨道的结合/抗结合特性,如在N(3)(7)(-中所见.
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