O. Hatozaki et Fc. Anson, INTRAMOLECULAR ELECTRON-TRANSFER WITHIN A WATER-SOLUBLE, FERROCENE-LABELED POLYACRYLATE, Journal of electroanalytical chemistry [1992], 420(1-2), 1997, pp. 195-199
A water-soluble polyanionic polyacrylate was rendered electroactive by
the covalent attachment of (on average) one ferrocene molecule to eac
h polymer chain. Electro-oxidation of the ferrocene labels produced fe
rricinium groups that could not be electro-reduced in dilute supportin
g electrolyte solutions (less than 0.1M). However, Ru(NH3)(6)(3+) coun
terions bound electrostatically to the oxidized polyanion could be ele
ctro-reduced and the resulting, bound Ru(NH3)(6)(2+) counterions rapid
ly reduced the ferrocenium groups on the same polyanionic chain by int
ramolecular electron transfer. These phenomena are demonstrated by mea
ns of cyclic voltammetry. Experimental and numerically simulated cycli
c voltammetric responses are compared to support the mechanism propose
d to account for the observed results which may be relevant to long ra
nge electron transfers in redox enzymes and across molecular monolayer
s on surfaces.