Coronenic coronoid

Chem., 29, 131 (1993). Coronenic Coronoids A Course in Chemical Enumeration. 

Exactly all the circular benzenoids 0 N S) with 5 > 18 can be perforated by a coronene hole to produce single coronoids 0(n 5). Then one has i T=n+6, 5=5 — 6. A detailed treatment on a complete enumeration of the isomers of the class 0 has been published (Cyvin BN, Brunvoll, Chen and Cyvin 1993). The smallest system of this class is kekulene. In the cited reference a coronoid with coronene hole(s) was referred to as "coronenic . We quote a nice sentence therefrom "A coronenic coronoid has a coronene corona hole. We shall not use the term "coronenic in the following, although it is analogous with our term "naphthalenic (Definition 3.3). A brief account on the title systems and their enumeration is given in the next two paragraphs. 

Cyvin BN, BrunvoU J, Chen RS, Cyvin SJ (1993) Coronenic Coronoids — A Course in Chemical Enumeration [in] Topological Aspects of Benzenoid Hydrocarbons and Related Structures (Cyvin SJ, Edit). Max—Planck—Institut fur Strahlenchemie, Mulheim a d Ruhr Match 29 131... 

It may seem unnecessary to bring in such artifacts as the above examples of non-polyhexes. Yet we find the discussion to be warranted. Ege and Vogler [28, 29], for instance, treated pyrene in a group together with coronene ([6]circulene) and six coronoids. Implicitly, the authors considered pyrene as [4]circulene and ascribed an inner perimeter of two edges to it. That leads to vertices of degree four as in one of the forbidden examples above. Therefore we claim that the interpretation of pyrene as [4]circulene is not justified. 

In the second example of Par. 3.5.3 the unique smallest multiple coronoid for = 7 was derived from coronene according to the algorithm under consideration. Another such system emerges from C25H13 benzo[/u]anthanthrene. This nonextremal benzenoid has 25 internal vertices (iV) against = 24 (cf. Table 3). On the other hand, its minimum number of parallel... 

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