Reactivity of ferrocenium cations with molecular oxygen in polar organic solvents: Decomposition, redox reactions and stabilization

The behaviour of chemically or electrochemically generated ferrocenium cations has been studied in some polar organic solvents (DMF, DMSO, acetonitrile, acetone, methylene chloride) under molecular oxygen. Adducts between oxygen and ferrocenium species can differently evolve according to the solvent (oxidizable or not) and the absence or the presence of another reagent. A rapid decomposition of ferrocenium cations is observed in the absence of another substrate. In the presence of some substrates and antioxidants, the stability of ferrocenium cations towards molecular oxygen notably increases and in some cases redox reactions take place with formation of ferrocene.