Dications of fluorenylidenes. The effect of substituent electronegativity and position on the antiaromaticity of substituted tetrabenzo[5.5]fulvalene dications

Amalia Levy, Amber Rakowitz, Nancy S. Mills

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

Oxidation of 3,6-disubstituted tetrabenzo[5.5]fulvalenes by SbF5 results in the formation of dications that behave like two antiaromatic fluorenyl cations connected by a single bond. Both fluorenyl systems exhibit the paratropic shifts and nucleus independent chemical shifts (NICS) characteristic of antiaromatic species. Comparison with analogous 2,7-disubstituted tetrabenzo[5.5]fulvalenes reveals that the antiaromaticity of the substituted ring system can be altered substantially by changes in the placement of the substituents, possibly due to changes in the delocalization of charge in the system. Substituents in the 3,6-position decrease the antiaromaticity because of the increase in the benzylic resonance compared to 2,7-substituents.

Original languageEnglish
Pages (from-to)3990-3998
Number of pages9
JournalJournal of Organic Chemistry
Volume68
Issue number10
DOIs
StatePublished - 16 May 2003
Externally publishedYes

ASJC Scopus subject areas

  • Organic Chemistry

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