Rate of electron transfer between cobalt complex ions in aqueous polyelectrolyte solutions

Abstract

The rate of electron transfer in the system (+)-tris-(o-phenanthroline)cobalt(III)–tris-(o-phenanthroline)cobalt(II) has been determined in dilute aqueous solutions of sodium poly(styrenesulphonate), sodium poly (vinylsulphonate), and sodium poly(phosphate). Electron exchange was followed by studying the change in optical rotation of the cobalt(III) complex. Powerful catalytic action on the exchange is exhibited by the polyelectrolytes, particularly sodium poly(vinylsulphonate), under appropriate experimental conditions. Further the rate of electron transfer between the two complex ions is, at a given concentration of the reactants, influenced in a marked and specific manner by varying polyion concentrations. An explanation of the correlation of the rate data with binding data is not feasible. The influence of forces other than coulombic ones in the interaction between macroions and counterions is, in fact, certainly very important in determining the behaviour of the system considered, notably in dilute solutions of sodium poly(styrenesulphonate).