Thermodynamics and Kinetics of Adsorption of Poly(amido amine) Dendrimers Surface Functionalized with Ruthenium(II) Complexes
1999; American Chemical Society; Volume: 15; Issue: 21 Linguagem: Inglês
10.1021/la9903752
ISSN1520-5827
AutoresKazutake Takada, Gregory D. Storrier, Moisés Morán, Héctor D. Abruña,
Tópico(s)Fuel Cells and Related Materials
ResumoThe thermodynamics and kinetics of adsorption of the redox-active tris(bipyridyl)ruthenium(II) pendant poly(amido amine) (PAMAM) dendrimers and bis(terpyridyl)ruthenium(II) pendant PAMAM dendrimers (generations 0, 1, 2, 3, and 4) have been studied using electrochemical methods. All of these metallodendrimers adsorb onto Pt electrodes at +0.8 V vs Ag/AgCl where the Ru sites of the dendrimers have 2+ charges and the adsorption thermodynamics are well characterized by the Langmuir adsorption isotherm. The kinetics of adsorption were found to be activation controlled with the rate constant decreasing with decreasing dendrimer generation. Electrochemically determined coverages were significantly larger than calculated values determined from the dimensions of the metallodenrimers obtained from molecular modeling. These comparisons suggest that upon adsorption, the dendrimers appear to compress to dimensions significantly smaller than those calculated.
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