The Reaction of Ethylenediamine with Cobalt (II) Perchlorate and Oxygen in Dilute Aqueous Solutions

Cobalt (II) perchlorate was reacted with ethylenediamine and molecular oxygen. Various mole ratios of ethylenediamine to cobalt (II) were oxygenated and studied by photometric, potentiometric, conductometric, magnetic susceptibility, freezing point depression, electron spin resonance and cobalt (II) extraction methods. The fact that the complex was brown in color, diamagnetic, contained ethylenediamine to cobalt to oxygen in a mole ratio of 4:2:1 was confirmed. The complex underwent elation to form a polymeric species with excess base. The complex could not be oxidized to a green paramagnetic complex by reacting it with sodium peroxydisulfate, potassium bromate, bromine or chlorine. Ammonia was added to a 2:1 mole ratio solution of ethylenediamine to cobalt (II) perchlorate before oxygenation. Upon oxygenation this solution also turned brown. This ammonia- containing-complex underwent no elation reaction and was postulated by analogy to contain ammonia: ethylenediamine:cobalt:oxygen in a mole ratio of 2:4:2:1. Crystals of this ammonia- containing-complex were obtained