Carbonyl dyes are dyes which comprise at least two conjugated carbonyl groups. Both

anthraquinone dyes Anthraquinone dyes are an abundant group of dyes comprising a anthraquinone unit as the shared structural element. Anthraquinone itself is colourless, but red to blue dyes are obtained by introducing electron donor groups such as hydroxy or amino ...

and indigo dyes belong to the group of carbonyl dyes. The most important natural dyes -

indigo Indigo is a deep color close to the color wheel blue (a primary color in the RGB color space), as well as to some variants of ultramarine, based on the ancient dye of the same name. The word "indigo" comes from the Latin word ''indicum'', m ...

Tyrian purple Tyrian purple ( grc, πορφύρα ''porphúra''; la, purpura), also known as Phoenician red, Phoenician purple, royal purple, imperial purple, or imperial dye, is a reddish-purple natural dye. The name Tyrian refers to Tyre, Lebanon. It is ...

, alizarin and

carmine Carmine ()also called cochineal (when it is extracted from the cochineal insect), cochineal extract, crimson lake, or carmine lake is a pigment of a bright-red color obtained from the aluminium complex derived from carminic acid. Specific code n ...

- have this partial structure. The most important synthetic carbonyl dyes are based on anthraquinone. The main advantages of carbonyl dyes are the possibility of reducing the carbonyl groups to water-soluble dienols (→

Vat dyes A value-added tax (VAT), known in some countries as a goods and services tax (GST), is a type of tax that is assessed incrementally. It is levied on the price of a product or service at each stage of production, distribution, or sale to the end ...

), which is advantageous in industrial applications. On the other hand, by introducing suitable electron donating groups, the absorption maximum of the resulting dyes can be shifted to almost any region of the VIS spectrum.{{citation, surname1=Heinrich Zollinger, title=Color Chemistry: Syntheses, Properties, and Applications of Organic Dyes and Pigments, edition=3., publisher=WILEY-VCH Verlag, location=Weinheim, at=pp. 255 ff., isbn=3-906390-23-3, date=2003 , url={{Google books, 0Ynge4E5rqYC, , page=255, plainurl=yes

Reduction/Oxidation of carbonyl dyestuffs / examples: anthraquinone and indigo

References

Dyes