Ferrocenes/ferrocenyls ferrocene-ferrocenium couple

Cyclic voltamograms of 4 and 8 show the reversible oxidation event to be shifted 0.30 V and 0.32 V, respectively, more positive than the ferrocene/ferrocenium redox couple. These data would suggest that the iron centers in 4 and 8 are much less capable of stabilizing a positive charge. It is logical to argue they would also form a much less stable a-ferrocenyl carbocation intermediate hence, we tend to rule out such a species in the homopolymerization of complex 4. 

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