Metal Complex Dyes

Metal complex dye are a family of dyes that contain metals coordinated to the organic portion. Many azo dyes, especially those derived from naphthols, form metal complexes by complexation of one of the azo nitrogen centers. Metal complex dyes are premetallised dyes that show great affinity towards protein fibers. In this dye one or two dye molecules are coordinated with a metal ion. The dye molecule is typically a monoazo structure containing additional groups such as hydroxyl, carboxyl or amino, which are capable of forming a strong co-ordination complexes with transition metal ions such as chromium, cobalt, nickel and copper.

Metal complex dyes belong to numerous application classes of dyes. For example, they are found among direct, acid, and reactive dyes. When applied in the dyeing processes, metal-complex dyes are used in pH conditions that are regulated by user class and the type of fiber type (wool, polyamide, etc).