Use of Charge-Charge Repulsion to Enhance π-Electron Delocalization into Anti-Aromatic and Aromatic Systems
Use of Charge-Charge Repulsion to Enhance π-Electron Delocalization into Anti-Aromatic and Aromatic Systems
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DOI：
10.1002/chem.201606036
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发表时间：
2017-02-01
影响因子：
4.3
通讯作者：
Klumpp, Douglas A.
中科院分区：
文献类型：
--
作者：
Sumita, Akinari;Gasonoo, Makafui;Klumpp, Douglas A.
对一系列9-芴基阳离子进行了研究，结果表明，增加杂环取代基上的电荷可以增强碳正离子体系的抗芳性。类似地，对一系列二苯并亚苯二烯基阳离子进行了研究，表明在碳正离子体系中，增加取代基上的电荷可以增强芳香性。这些研究包括使用稳定离子条件和低温核磁共振直接观察二价和三价物质。利用DFT计算进一步表征了这些离子的结构，证实了高电荷有机离子在4n或4n+ 2 pi-体系中可能表现出不寻常的pi-电子分布和电子离域。
A series of 9-fluorenyl cations has been studied and it is shown that increasing charge on a heterocyclic substituent group enhances the anti-aromatic character of the carbocation system. Similarly, a series of dibenzosuberenyl cations has been studied and increasing charge on a substituent group is shown to enhance aromatic character in the carbocation system. These studies include the direct observations of dicationic and tricationic species using stable-ion conditions and low temperature NMR. The structures of these ions were further characterized using DFT calculations, confirming that highly charged organic ions may exhibit unusual distributions of pi-electrons and delocalization of electrons in 4n or 4n+ 2 pi-systems.