CRYSTALLOGRAPHIC STUDIES OF INTERMOLECULAR AND INTRAMOLECULAR INTERACTIONS REFLECTED IN AROMATIC CHARACTER OF PI-ELECTRON SYSTEMS
CRYSTALLOGRAPHIC STUDIES OF INTERMOLECULAR AND INTRAMOLECULAR INTERACTIONS REFLECTED IN AROMATIC CHARACTER OF PI-ELECTRON SYSTEMS
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DOI：
10.1021/ci00011a011
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发表时间：
1993-01-01
期刊：
影响因子：
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通讯作者：
KRYGOWSKI, TM
中科院分区：
文献类型：
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作者：
KRYGOWSKI, TM
重新定义了一种新的芳香性定量度量方法HOMA(谐振子芳香性度量)，并将其与Jug和Koester的共振坐标概念联系起来。在它的新版本中，Homa指数可以用来估计由CC、CN、CO、CP、CS、NN和NO键组成的pi电子系统(分子、离子或其碎片)的芳香性。结果表明，即使芳香族化合物的稳定是由于Sigma电子结构倾向于保持相同的键长，芳香族特征也主要是体系的pi电子性质的结果。Homa ind‘’在不同分子和离子体系中对苯环的应用表明，芳香性与平面形变的关系较弱，而与分子间的氢键网络、推拉式的协同取代基相互作用以及稠苯烃中苯环之间相互连接的拓扑结构密切相关。
An old quantitative measure of aromatic character named HOMA (harmonic oscillator measure of aromaticity) is reformulated and related to the Jug and Koester concept of resonance coordinate. In its new version, the HOMA index can be used to estimate an aromatic character of pi-electron systems (molecules, ions, or their fragments) built up of the following bonds: CC, CN, CO, CP, CS, NN, and NO. It is shown that even if aromatic stabilization is due to sigma-electron structure inclined to maintain equal bond lengths, the aromatic character is mainly a result of pi-electron properties of the system. Application of the HOMA ind'' to benzene rings in various molecular and ionic systems showed that the aromatic character depends rather weakly on deformation from planarity whereas it may be strongly dependent on the intermolecular H-bonding net as well as on cooperative substituent interactions of push-pull type and on the topology of a mutual link between benzene rings in condensed benzenoid hydrocarbons.