Visible absorption spectra of substituted ferricenium cations

Abstract

The magnitude of the extinction coefficient and the shift on substitution show that the band at 16,200 cm^–1 in the absorption spectrum of Fe(C₅H₅)₂ ⁺, which formerly was attributed to a 3d–3d ligand-field transition, is due to a ligand-to-metal e_1u→e_2g charge-transfer transition.