Polarography of some coordination compounds of platinum

Abstract

The hydroxo- and chloropentammineplatinum(IV) ions have been studied in potassium chloride, potassium nitrate, and potassium nitrate plus ammonia. Bromopentammineplatinum(IV) ion was studied in potassium chloride. All the ions were reduced irreversibly, producing waves with id proportional to concentration. The wave heights corresponded to two-electron reductions. The effect of substituting an electronegative group for an ammonia molecule in the hexammineplatinum(IV) ion was to shift the half-wave potential in the order                    -Br ≤ -Cl < -NH3 < -OH Continuous discharge began in every case at c. -1.3 V and was assumed due to the evolution of hydrogen consequent to the further reduction of the complex to platinum metal.