Fowler Patrick W, Mizoguchi Noriyuki, Bean David E, Havenith Remco W A
Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
Chemistry. 2009 Jul 13;15(28):6964-72. doi: 10.1002/chem.200900322.
Double aromaticity of neutral, planar rings of carbon atoms is demonstrated through visualisation of the induced ring currents, mapped at the ipsocentric B3LYP/6-31G(d)//B3LYP/6-31G(d) level for species C(6) to C(30), with onset of delocalised current in the in-plane pi system at C(10)/C(11). Both in-plane and conventional out-of-plane pi systems have diatropic/paratropic current in accordance with the Hückel rule, with 4 m+2 occupation of the out-of-plane pi system taking precedence, as predicted by simple nesting of Frost-Musulin diagrams. The current-density maps show characteristic double-doughnut and double-track topographies for out-of-plane and in-plane ring currents, respectively, both governed by a common framework of angular momentum rules.
通过诱导环电流的可视化，证明了中性平面碳原子环的双重芳香性。对于C(6)至C(30)物种，在以自身为中心的B3LYP/6-31G(d)//B3LYP/6-31G(d)水平上绘制诱导环电流，在C(10)/C(11)处的面内π体系中出现离域电流。根据休克尔规则，面内和面外的传统π体系都有抗磁/顺磁电流，如弗罗斯特-穆苏林图的简单嵌套所预测的那样，面外π体系优先占据4m+2。电流密度图分别显示了面外和面内环电流的特征性双环面和双轨形貌，两者都受角动量规则的共同框架支配。
