Ring signatures for benzenoids with up to seven rings,Part 2: Pericondensed systems |
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Authors: | Alexandru T Balaban Milan Randić |
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Institution: | 1. Department of Marine Sciences, Texas A&M University at Galveston, 5007 Avenue U, Galveston, TX 77551;2. National Institute of Chemistry, Hajdrihova 19, SI‐1001 Ljubljana, Slovenia |
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Abstract: | An array of integers pij indicate in how many of the K resonance structures one finds 6 > i > 0 π‐electrons in the corresponding ring (which is labeled with capital letters A through a subsequent letter up to G). The index j for the rows indicates the ring type, denoted by capital letters (that is, j = 1 stands for A, j = 2 stands for B, etc.). Row sums lead to π‐electron ring partitions after division by the number K of resonance structures. Column sums lead to a sequence of seven integers (Ri sequence) which after division by K affords the ri sequence; this is finally converted into the signature of the benzenoid si sequence). The analysis of signatures for pericondensed benzenoids with h = 4 through 7 benzenoid rings has revealed interesting regularities and correlations with structure, and has also allowed a confirmation of Clar's theory by investigating five isomeric dibenzopyrenes. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 |
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Keywords: | pericondensed benzenoids π ‐electron ring partitions signature of benzenoid hydrocarbons Kekulé valence structures Clar structures |
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