The Influences of Ortho Substituents on ¹³C-NMR Chemical Shifts of (ο-Substituted phenyl)ferrocenes -Studies on Ferrocene Derivatives. III.-

Abstract

On (ο-substituted phenyl)ferrocenes, the measurement of ¹³C-NMR spectra was carried out and assignments of the carbons of cyclopentadienyl rings were determined. The chemical shift of the α-carbon was found to be influenced by steric perturbation effect, and that of the β-carbon was influenced by inductive effect. On the other hand, both effects were recongnized as for the ipso-carbon. Further, unusual chemical shifts were found on the following carbons: (i) the a-carbon of (ο-nitro- and o-methoxycarbonylphenyl)ferrocenes, (ii) the α-, β- and 1′-carbons of (ο-hydroxyphenyl)ferr ocene. It was considered that these peculiarities were provoked by the charactaristic conformation of these three ferrocenes (Figs.2 and 4).