Peer-Reviewed Journal Details
Mandatory Fields
Annibaldi V.;Breslin C.
Journal of Electroanalytical Chemistry
Electrochemistry of viologens at polypyrrole doped with sulfonated β–cyclodextrin
4 ()
Optional Fields
Cation exchange Cyclodextrin Paraquat Polypyrrole Viologens
© 2018 Elsevier B.V. The electrochemistry of methyl, ethyl and benzyl viologens was studied at polypyrrole doped with sulfonated cyclodextrin, PPysβ–CD, a cation exchange polymer. Three reduction waves were observed corresponding to the reduction of the viologen (V2+) to the radical cation (V•+) followed by the neutral compound (V0) and a third intense peak. This third reduction peak was associated with the ingress of V2+ as the PPysβ–CD film is reduced. As the incorporated V2+ is reduced to the neutral viologen, the influx of more V2+ occurs to achieve charge balance and this repeated influx and reduction of V2+ gives an intense reduction wave. These processes were only observed with sβ–CD as a dopant and this was attributed to the formation of an ion pair between the anionic cyclodextrin and the viologen. Lower diffusion coefficients and rate constants were observed for the reduction of V2+ and V•+ on adding an excess of sβ–CD to the viologen solution. Linear calibration curves were obtained extending from 1.0 μM to 80 μM when the PPysβ–CD was employed as a sensor for methyl viologen. While the PPysβ–CD is not suitable for the detection of low nM concentrations, the uptake and extraction of MV2+ was observed on polarising the PPysβ–CD in a solution of the viologen, highlighting the dual action of the polymer.
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