Explicit formulas are given for the number of Kekul6 structures of some classes of corona-condensed benzenoids. A general algorithm for cycloarenes is reported.
The number of Kekulé structures for primitive coronoids (cycloarenes)
✍ Scribed by S.J. Cyvin
- Publisher
- Elsevier Science
- Year
- 1988
- Tongue
- English
- Weight
- 374 KB
- Volume
- 147
- Category
- Article
- ISSN
- 0009-2614
No coin nor oath required. For personal study only.
✦ Synopsis
The number of Kekult structures for primitive coronoids is studied. The systems have obvious counterparts within a class of hydrocarbons known as cycloarenes. Complete solutions are given for centrosymmetrical primitive coronoids and those with trigonal or hexagonal symmetries. The technique is based on considerations of single unbranded chains associated with the coronoids. A lemma (nor proved here) concerning unbranched chains in general plays an important role.
📜 SIMILAR VOLUMES
It is known that an alternative algorithm to the Gordon-Davidson algorithm for counting the Kekule valence structures of catacondensed non-branched benzenoid hydrocarbons is a reformulation of the original algorithm. Recently an alternative algorithm [ 1,2] to the Gordon-Davison (GD) algorithm [ 31
A novel method for the calculation of the number Kof Kekult structures of benzenoid hydrocarbons is presented. K= ) det WI, where W is a matrix whose entries are the K values of certain fragments of the benzenoid system considered.
The linear dependence, previously claimed, of the total -rr-electron energy (E~) of isomeric benzenoid hydrocarbons on the number of Kekul6 structures (K) is found to be a satisfactory approximation only for benzenoids having eight or fewer six-membered rings (h ~< 8), and is violated if h >1 9. For