Electron transfer processes involving ferrocenes. Electrogeneration and reactivity of an unusual species,the monocyclopentadienyliron radical

The very reactive cyclopentadienyliron species, (RC₅H₄)Fe, are relatively easily generated by electrochemical reduction of appropriately substituted and readily available ferrocenes. Thus (MeCOC₅H₄)Fe has been generated by monoelectronic reduction of (MeCOC₅H₄)₂Fe; it reacts with CO leading, after further reduction, to the acetyl cyclopentadienyldicarbonyliron anion. Reactions of this anion give ring-substituted cyclopentadienyldicarbonyliron derivatives containing the electron-withdrawing MeCO substituent.