Evaluation of Ring-Strain Effects in Cycloalkene-Fused Octadehydro[14]annulenes

Abstract

The possibility of ring strain as the cause of bond localization in metalloarene-fused octadehydro[14]annulenes is addressed. It was found that strain-induced bond localization is not observable in the mildly aromatic annulenes previously used to compare the degree of delocalization in CpCo(cyclobutadiene) relative to ferrocene and benzene.

Key words

annulenes - aromaticity - cross-coupling - ring current

References

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7

The ring strain in cyclobutene [8a] is 30.6 kcal mol^-1 compared to 32.0 kcal mol^-1 for cyclobutadiene. [8b] Cyclopentene [8a] has a ring strain of 6.8 kcal mol^-1 compared to 2.9 kcal mol^-1 for cyclopentadiene. [8a]

10

Calculations were done on an SGI workstation using SPARTAN version 5.1.3.