Dias Jerry Ray
Department of Chemistry, University of Missouri, Kansas City, Missouri 64110-2499, United States.
J Phys Chem A. 2021 Sep 30;125(38):8482-8497. doi: 10.1021/acs.jpca.1c05669. Epub 2021 Sep 21.
This paper contributes to the further understanding of bond resonance energy (BRE), circuit resonance energy (CRE), and ring currents (RC = ) as indices for the measure of local ring aromaticity and topological resonance energy (TRE) and magnetic resonance energy (MRE) as indices for the measure of global molecular aromaticity. Calculations of ring currents in the 3-ring polycyclic hydrocarbons of anthracene, biphenylene, phenalenyl, and -terphenyl are demonstrated. This comparative study provides new molecular insights. A number of shortcut techniques are briefly illustrated. -Terphenyl is a benzenoid total resonant sextet (TRS) and biphenylene is shown to be a nonbenzenoid TRS, i.e., both obey Clar's sextet principle. -Terphenyl has only ring circuits, whereas anthracene, biphenylene, and phenalenyl have ring circuits and larger circuits engulfing the ring circuits. The perimeter circuits of anthracene, biphenylene, and phenalenyl engulf all other circuits, thus leading to the definition of MRE. By these several aromatic indices, the monocation, monoanion, and monoradical of phenalenyl are equally aromatic. The agreement in the prediction of local ring aromaticity between the three indices of -BRE, BRE, and CRE is evaluated.
本文有助于进一步理解作为衡量局部环芳香性指标的键共振能（BRE）、电路共振能（CRE）和环电流（RC = ），以及作为衡量全局分子芳香性指标的拓扑共振能（TRE）和磁共振能（MRE）。展示了对蒽、联苯撑、苊烯和 - 三联苯的三环多环烃中环电流的计算。这项比较研究提供了新的分子见解。简要说明了一些捷径技术。 - 三联苯是一种苯型全共振六隅体（TRS），联苯撑被证明是一种非苯型TRS，即两者都遵循克拉尔六隅体原理。 - 三联苯只有环电路，而蒽、联苯撑和苊烯既有环电路又有包围环电路的更大电路。蒽、联苯撑和苊烯的周边电路包围了所有其他电路，从而引出了MRE的定义。通过这些几个芳香性指标，苊烯的单阳离子、单阴离子和单自由基具有同等的芳香性。评估了 - BRE、BRE和CRE这三个指标在局部环芳香性预测方面的一致性。
