Metallized bis-formazans

Abstract

Heavy-metal-containing bisformazan dyestuffs of the formula ##STR1## WHEREIN A.sub.1, A.sub.2, B.sub.1 and B.sub.2 are the same or different and each represents an unsubstituted or substituted o-phenylene radical or an o-naphthylene radical, R.sub.1 and R.sub.2 are the same or different and each represent a monovalent organic radical, Me.sub.1 and Me.sub.2 each represent nickel or copper, X.sub.1 and X.sub.2 are the same or different and each represents a metal-binding substituent connected to A.sub.1, B.sub.1, A.sub.2 or B.sub.2 in a position ortho to that to which the nitrogen is linked, Y represents the radical of a dibasic carboxylic acid or a radical which is derived from an, at least, bifunctional heterocyclic compound, Z represents a salt-forming water-solubilizing group, dissociating acid in water, selected from --SO.sub.3.sup..crclbar. M.sym. and --COO.sup..crclbar. M.sup..sym. wherein M.sup..sym. represents a cation, N represents a number from 2 to 6, and Wherein aromatic radicals present may contain further substituents known per se for use in azo dyestuffs, and wherein the grouping --NH--Y--HN-- is bound directly or via a bridging member to a ring carbon atom of A.sub.1, A.sub.2, B.sub.1, B.sub.2, R.sub.1 or R.sub.2 , which bis-formazans are substantive dyestuffs suitable for the dyeing or printing of textile material made from natural or regenerated cellulose. The aforesaid bis-formazan dyestuffs are distinguished by high coloring strength and substantivity to cellulose textile material. The dyeings obtained therewith are of a pure shade of color and have good fastness properties, especially to light and wet.