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-)Cp2*Fe+

A major interest in ferrocenium compounds arises from their usefulness as selective oxidants to prepare mixed-valence metallocenic stable compounds. In this paper, Cp2FeBAr4' = ((3,5(CF3)(2)C6H3)(4)B-)Cp2Fe+) (a), and Cp-2*FeBAr4' = ((3,5(CF3)(2)C6H3)(4)B-)Cp-2*Fe+) (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*Co-II(C8H6)Fe-II(C8H7)] with stoichiometric quantities of Cp2FeBAr4' or Cp-2*TFeBAr4' where [Cp*Co-III(C8H6)Fe-II(C8H7)]BAr4' was exclusively obtained. All salts that have BAr4-' 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 NaBAr4' as supporting electrolyte. Single-crystal structural determination of a and b was also achieved. (C) 2000 Elsevier Science S.A. All rights reserved.