Metal complexes of azo-dyestuffs. Part II. The reaction of cobalt halides with aminoazo-compounds

Cobalt chloride reacts with oo′-diaminoarylazo-compounds in ethanol to form 2:1 cobalt(III) complexes in which one proton is lost from each ligand molecule. The introduction of N-alkyl groups into the oo′-diaminoarylazo-compound exerts a profound influence on the nature of the products, and three different types of 1:1 cobalt(II) complex have been isolated. In certain cases these can undergo further reaction to form 2:1 cobalt(III) complexes. A scheme for the formation of 2:1 cobalt(III) complexes of oo′-diaminoarylazo-compounds is suggested in the light of the experimental results.