pH-induced, long-range electron transfer across a thin polymeric film
A bilayer of thin polymeric films on a glassy carbon electrode was prepared by electropolymerizing ((bpy)/sub 2/Os(vpy)/sub 2/)(PF/sub 6/)/sub 2/ (bpy = 2,2'-bipyridine, vpy = 4-vinylpyridine), to form the inner layer, and adding as an outer layer Nafion into which the complex ((bpy)/sub 2/(py)Ru(OH)/sub 2/))/sup 2 +/ (py = pyridine) was ion exchanged. The Os(III)/(II) couple is pH independent with E/sub 1/2/ = 0.55 V while E/sub 1/2/ for the Ru(III)/(II) couple varies from 0.76 to 0.20 V over the pH range 1 to 10, (bpy)/sub 2/(py)Ru/sup III/-OH/sup 2 +/ + e/sup -/ + H/sup +/ ..-->.. (bpy)/sub 2/(py)Ru/sup II/-OH/sub 2//sup 2 +/. At pH 5.0 the potentials of the couples in the inner and outer films are the same. By decreasing the pH in the external solution to pH 2.0 with the electrode potential held at 0.60 V (i.e., both films initially as M(III)), a long-range electron transfer occurs from the electrode through the intervening Os film to Ru(III) sites in the outer film. Upon returning the pH in the external solution to 5.0, the reverse process occurs, and long-range electron transfer from Ru(II) to the electrode is mediated by the inner film.
- Research Organization:
- Univ. of North Carolina, Chapel Hill
- OSTI ID:
- 5497002
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 90:11; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
400400* -- Electrochemistry
AZINES
BIPYRIDINES
COMPLEXES
DATA
ELECTRODES
ELECTRON EXCHANGE
ELECTRON TRANSFER
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OSMIUM COMPLEXES
PH VALUE
PYRIDINES
RUTHENIUM COMPLEXES
TRANSITION ELEMENT COMPLEXES
VOLTAMETRY