Selective oxidants for organometallic compounds containing a stabilising anion of highly reactive cations: (3,5(CF3)2C6H3)4B−)Cp2Fe+ and (3,5(CF3)2C6H3)4B−)Cp*2Fe+

A major interest in ferrocenium compounds arises from their usefulness as selective oxidants to prepare mixed-valence metallocenic stable compounds. In this paper, Cp2FeBAr′4=((3,5(CF3)2C6H3)4B−)Cp2Fe+) (a), and Cp*2FeBAr′4=((3,5(CF3)2C6H3)4B−) Cp*2Fe+) (b) are reported. These compounds have wide applications in the obtention of new organometallic salts with improved stability. The selective oxidation capacity of compounds a and b was investigated by the reaction of [Cp*CoII(C8H6)FeII(C8H7)] with stoichiometric quantities of Cp2FeBAr′4 or Cp*2FeBAr′4 where [Cp*CoIII(C8H6)FeII(C8H7)]BAr′4 was exclusively obtained. All salts that have BAr′4− as counterion showed an enhanced solubility in low-polarity solvents, especially in diethyl ether. This fact allowed us to perform non-conventional measurements like cyclic voltammetry in diethyl ether as solvent with NaBAr′4 as supporting electrolyte. Single-crystal structural determination of a and b was also achieved.