Metal complexes of azo-dyestuffs. Part I. The cobalt-catalysed cleavage of 2,2′-bis(dialkylamino)azobenzenes

Abstract

2,2′-Bis(dimethylamino)azobenzene decomposes in dilute ethanolic hydrochloric acid giving 1-methylbenzimidazole and o-dimethylaminoaniline. A similar cleavage occurs when the azo-compound reacts with hydrated cobalt chloride in ethanolic solution and dichlorobis-(1-methylbenzimidazole)cobalt(II) and o-dimethylaminoaniline are formed. Under anhydrous conditions, 2,2′-bis(dimethylamino)azobenzene reacts with cobalt chloride in ethanolic solution to give chloro-[2,2′-bis(dimethylamino)azobenzene]cobalt(II) chloride. The latter decomposes in dry ethanolic solution to dichlorobis-(1-methylbenzimidazole)cobalt(II) and o-dimethylaminoaniline.