Texas A & M University at Galveston, 5007 Avenue U, Galveston, Texas 77551, USA.
J Phys Chem A. 2010 May 13;114(18):5870-7. doi: 10.1021/jp1002148.
Local aromaticity in rings of conjugated hydrocarbons can be measured in a variety of ways. In the present paper, we concentrate on two of these, namely, EC, i.e., the pi-electron content or pi-electron partition, and ef, the energy effect of cycles. For the central ring in five bipartite conjugated hydrocarbons (anthracene, triphenylene, perylene, coronene, and biphenylene), it was found that EC and ef values are modified in a consistent and predictable manner by annelation with benzenoid rings. Equations are presented for computing EC and ef values for the central ring in terms of three integers representing the numbers of annelated benzenoid rings (A, L, and G for angular, linear, and geminal annelation, respectively). The coefficients of A and G are positive (A > G) and the coefficient of L is negative for benzenoids, but for biphenylene, the situation is reversed for coefficients in the correlation for ef values.
在共轭烃环中，可以通过多种方法测量局部芳香性。在本文中，我们集中讨论其中的两种方法，即 EC，即π电子含量或π电子分配，以及 ef，即环的能量效应。对于五个双分共轭烃（蒽、三苯、并四苯、蔻和联苯）的中环，发现通过与苯并环的稠合，EC 和 ef 值以一致且可预测的方式发生变化。本文提出了一种计算中环 EC 和 ef 值的方法，该方法基于三个整数表示稠合苯并环的数量（分别为角状、线性和并合稠合的 A、L 和 G）。对于苯并环，A 和 G 的系数为正（A>G），而 L 的系数为负，但对于 biphenylene，ef 值相关系数中的系数情况则相反。
