Electrochemical behaviour and X-ray structure of (η-cyclopentadienyl)(4–5-η–2-methoxycarbonylcyclopent-4-en-1,3-ylene)cobalt

Abstract

A study has been made of the electrochemical properties in non-aqueous media, crystal structure, and ¹H and ¹³C n.m.r. spectra of the title complex [Co(C₅H₅)(C₅H₅CO₂Me)]. The structural studies indicate that, in the cyclopentadiene ring, the CO₂Me group occupies the exo position with respect to the metal. The unusual oxidation of the complex into the substituted cobalticinium salt is not due to its geometry, but probably to the influence of the CO₂Me group on the formation of the radical cation obtained by one-electron oxidation. Evidence for the existence of the radical cation of (1a) is provided by cyclic voltammetry.