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Electrochemical and Adsorption Properties of PAMAM Dendrimers Surface-Functionalized with Polypyridyl Cobalt Complexes

2001; American Chemical Society; Volume: 105; Issue: 12 Linguagem: Inglês

10.1021/jp002930a

1520-6106

Kazutake Takada, Gregory D. Storrier, Jonas I. Goldsmith, Héctor D. Abruña,

Polymer Surface Interaction Studies

Polyamidoamine dendrimers (generations 1 and 3) surface-modified with terpyridyl cobalt complexes have been prepared and characterized by electrochemical and EQCM (electrochemical quartz crystal microbalance) techniques. EQCM studies of the dendrimer complexes show that they deposit onto a Pt electrode following the Co(II/I) reduction process and that the resulting films prevent further deposition upon successive potential scanning. The effects of electron self-exchange were observed for Co(I/II) redox processes for adsorbed layers of the dendrimers. Further, the thermodynamics and kinetics of adsorption of the dendrimers have been studied using electrochemical methods. These metallodendrimers adsorb (up to a monolayer equivalent) onto Pt electrodes at −0.20 V vs Ag/AgCl, where the Co sites have +2 charges, and the adsorption thermodynamics is well characterized by the Langmuir adsorption isotherm. The kinetics of adsorption is activation-controlled and the rate constant is larger for the higher generation (i.e., generation 3) metallodendrimer.