Asymmetrical 1:2 chromium and cobalt complexes of further substituted 6- or 7-amino-1-hydroxy-2-(nitro-phenylazo)-3-sulfonapthalenes

Abstract

Complexes of the formula ##STR1## which are in free acid or salt form, and mixtures thereof, wherein each of R.sub.1 and R.sub.3 is independently hydrogen, C.sub.1-4 alkyl or C.sub.1-4 alkyl monosubstituted by hydroxy, amino, sulfo or carboxy, each of R.sub.2 and R.sub.4 is independently hydrogen; C.sub.1-4 alkyl; C.sub.1-4 alkyl monosubstituted by hydroxy, amino, sulfo or carboxy; --COR.sub.5 ; --COOR.sub.6 or --CONHR.sub.7, M is chromium or cobalt, and M.sub.K.sup..sym. is hydrogen or a non-chromophoric cation, useful for dyeing or printing, materials such as natural and synthetic polyamides and particularly artificially produced oxide layers on aluminum and aluminum alloys.

Dependencies are inferred from the claim text.