Charge Trapping by Anionic Quinones Electrostatically Bound to a Highly Charged Cationic Quinone-Viologen Polymer or a Cationic Poly(3-viologen-thiophene)

Article abstract of DOI:10.1021/j100124a045

Charge associated with quinone reduction is trapped at low pH in systems composed of sulfonated anthraquinones electrostatically bound to a polymer derived from a monomer consisting of a quinone unit flanked by two viologen units.Each monomer repeat unit carriers 6 equiv of positive charge which can be charge compensated by monosulfonated anthraquinone to yield a quinone:viologen ratio of nearly 7:2.At low pH, electrostatic binding is persistent, and the amount of trapped charge is 90percent of the theoretical maximum.Some of the electrostatically bound quinone can be replaced with Fe(CN)6(^3-) to allow mediated release of trapped charge via the Fe(CN)6(^3-/4-) redox couple.I(^-) is blocked from entering the polymer and thus does not mediate release of charge.Electrostatic binding of anionic quinones to a thiophene polymer with pendant viologen units has also demonstrated.This polymer system has the unique property of having built-in mediators for both the reduction (charge trapping) and oxidation (charge release) of the electrostatically bound anthraquinone.