Properties of reduced viologens in Nafion films deposited on tin dioxide electrodes

Abstract

Optical spectroscopy and cyclic voltammetry were used to study the monomer-dimer equilibrium of the one-electron reduction products of methyl viologen (MV2+), 1-methyl-1'-(3-sulfonatopropyl)-4,4'bipyridinium (MPVS+), and l,l/-bis(sulfonatopropyl)-4,4'-bipyridinium (SPV) in Nafion films deposited on SnOs electrodes. In Nafion the equilibrium constants are considerably smaller than in water and they are affected by the viologen loading.

Amperometric and impedimetric characterization of a glutamate biosensor based on Nafion® and a methyl viologen modified glassy carbon electrode

“…It should be emphasized that some biosensors undergo different modification steps with the aim of getting good selectivity. Viologens, derivatives of 4,4 -bipyridyl, continue to play an important role as electron relays in systems in which electron transfer is initiated by electrochemical processes (Johansen et al, 1992). They have been widely used as mediators for different amperometric enzyme biosensors such as glucose oxidase biosensors (Hu et al, 1999;Cen et al, 2003;Liu et al, 2004, Ghica and and nitrate reductase biosensors (Moretto et al, 1998;Glazier et al, 1998;Wang et al, 2006).…”

“…They exhibit fast reversible electrochemical responses at negative redox potentials which make them useful as redox mediators for numerous enzymatic reactions (De Lacey et al, 1995;Ghica and Brett, 2005). Of special significance are the reversibility of their redox processes and the chemical properties of their one-electronreduction products (Johansen et al, 1992). The structure of methyl viologen consists of a hydrophobic part that is capable of hydrophobic-hydrophobic interaction with Nafion ® and two cationic pyridinum groups that undergo ion exchange with the sulphonate sites of Nafion ® polymer chains.…”

Facile Dimerization of Viologen Radical Cations Covalently Bonded to β-Cyclodextrin and Suppression of the Dimerization by β-Cyclodextrin and Amphiphiles

“…The dimerization of viologen radical cations is greatly enhanced by the presence of low concentrations of anionic surfactants 18,19 or polyelectrolytes 19,20 or by Nafion films, [21][22][23] and the phenomena have been attributed to the concentrating effect of the anionic microparticles or films for the cationic species. The radical cations of unsymmetric viologens with long hydrocarbon chains [24][25][26] or symmetric viologens with relatively long hydrocarbon chains [27][28][29][30] form much more stable dimers than C 1 C 1 V •+ .…”

Engineering Dendritic Aptamer Assemblies as Superior Inhibitors of Protein Function

“…Rabani et al. showed that, in Nafion films deposited on SnO 2 electrodes, the dimerization of 1 ⋅+ was weakened 53. Buttry et al.…”