ASSOCIATION OF ELECTROACTIVE COUNTERIONS WITH POLYELECTROLYTES .4. COORDINATIVE BINDING OF RU(EDTA) TO POLY(4-VINYLPYRIDINE)

The coordination of Ru(III)(edta)OH2- and Ru(II)(edta)OH22- (edta = ethylenediaminetetraacetate) to poly(4-vinylpyridine) (PVP) dissolved in aqueous acid was investigated with electrochemical techniques. Rotating disk voltammetry provided estimates of the diffusion coefficients of the polymer-metal complex. The diffusional rate of the Ru(III)(edta)PVP complex, but not the Ru(II)(edta)PVP complex, is enhanced substantially by homogeneous electron transfer between Ru(III)(edta) centers bound to the PVP and Ru(II)(edta)OH22- complexes generated at the electrode surface. The diffusion coefficient measured for the Ru(II)(edta)PVP complex, 1.4 x 10(-7) cm2 s-1, provides an estimate of the diffusion coefficient for the protonated PVP chains themselves.