Association constant of conductive poly(o-phenylenediamine) with halogenide ions

An electrically conductive polymer, poly(o-phenylenediamine) (PoPD) was found to be soluble in dimethylsulfoxide (DMSO) without any pretreatment. The PoPD dissolved in the DMSO solution was in an anion-doped state, and the cyclic voltammogram of dissolved PoPD obviously showed two reversible redox waves. The cyclic voltammograms were measured in DMSO solutions containing halogenide ions. The redox potential shifted with the concentration of the halogenide ion. The relationship between the potential shift and the concentration of the halogenide ion determined the relative association constant of PoPD for four halogenide ions: 104 mol−1 dm−3 for F; 32 mol−1 dm−3 for Cl−1; 29 mol−1 dm−3 for Br− and 9 mol−1 dm−3 for I−.