The novel series of conjugated systems called altans, defined nearly a decade ago, was subsequently extended to multiple (“iterated”) altans, and their magnetic properties were calculated by Monaco and Zanasi using the ab initio ipso-centric formalism. Such properties of the single (“mono”) altans of corannulene and coronene, calculated by this sophisticated ab initio approach, had earlier been compared with those calculated via the rudimentary Hückel–London–Pople–McWeeny (HLPM) method—a parameter-free topological, quasi graph-theoretical approach requiring knowledge only of the conjugated system’s molecular graph and the areas of its constituent rings. These investigations are here extended to double and triple altans. HLPM bond currents in several neutral mono altans are found to differ from those in the corresponding dianion only in those bonds that lie on the structures’ perimeters, while the HLPM bond currents in all bonds in the neutral double and triple altans of corannulene and coronene are precisely the same as in the respective dianions. Some rationalization of these unexpected phenomena is offered in terms of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) nature of the role played by the lone nonbonding orbital in each of the neutral species and its respective dianion.

中文翻译：

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拓扑环电流和债券电流中的某些中性和阴离子Altans和迭代Altans碗烯和蔻的

该新型共轭系列系统调用的altans，限定大约十年前，随后扩展到多个（“迭代”）altans，和它们的磁性性能通过摩纳哥和ZANASI使用从头计算本位-centric形式主义。这种复杂的从头算方法计算得出的单环戊二烯和二苯并呋喃的单（“单”）乙炔的这种性质，早先已与通过基本Hückel-London-Pople-McWeeny（HLPM）方法（无参数）进行了比较。拓扑，准图论方法仅需要了解共轭体系的分子图及其组成环的面积。这些调查在这里扩展到双重和三重阿尔丹斯。发现在几个中性单al醛中的HLPM键电流与相应二价阴离子的不同之处仅在于结构周边上的那些键，而在中性双环和三重of喃和co烯的所有键中的HLPM键电流均是与各自的双音完全相同。对这些意外现象的某种合理化是根据每个中性物种及其各自的二价阴离子中唯一的非键合轨道所起的作用的最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）性质提供的。