Negative hyperconjugation in phosphorus stabilized carbanions.
Negative hyperconjugation in phosphorus stabilized carbanions.
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DOI：
10.1021/jo7025756
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发表时间：
2008-02
期刊：
影响因子：
--
通讯作者：
T. Leyssens;D. Peeters
中科院分区：
文献类型：
--
作者：
T. Leyssens;D. Peeters
电子福井函数用于定性电子证明磷稳定碳负离子中碳孤对向sigma* P-Y和P-O轨道的背键存在。NBO分析被用来研究这种负超共轭相互作用的能量，电子和结构的影响。所观察到的能量稳定性确实可以归因于孤对电子向反键轨道的离域。这种离域还导致了与其中性对应物相比，阴离子化合物观察到的较短的P-C键、较长的P-Y（P-O）键和较宽的Y-P-Y角。从电子NBO分析中可以清楚地看出，含磷官能团最好描述为σ供体/π受体。
The electronic Fukui function is used to give qualitative electronic proof on the existence of back-bonding from the carbon lone pair toward the sigma* P-Y and P-O orbitals in phosphorus stabilized carbanions. NBO analyses are used to investigate the energetic, electronic, and structural impacts of this negative hyperconjugation interaction. The observed energetic stabilization can indeed be attributed to the electronic delocalization of the lone pair toward the antibonding orbitals. This delocalization is furthermore responsible for the shorter P-C bonds, longer P-Y (P-O) bonds, and wider Y-P-Y angles observed for the anionic compounds compared to their neutral counterparts. From the electronic NBO analysis it becomes clear that phosphorus containing functional groups are best described as sigma donor/pi acceptors.