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English: Reaction scheme for the diazo coupling of benzenediazonium chloride with aniline, forming 4-(phenyldiazenyl)aniline (description copied from File:Azo-coupling-B-2D-skeletal.png) ACS standard.
In organic chemistry, an azo coupling is an reaction between a diazonium compound (R−N≡N +) and another aromatic compound that produces an azo compound (R−N=N−R’).In this electrophilic aromatic substitution reaction, the aryldiazonium cation is the electrophile, and the activated carbon (usually from an arene, which is called coupling agent), serves as a nucleophile.
The following other wikis use this file: Usage on fi.wikipedia.org Diatsoniumsuolat; Atsokytkentä; Usage on hu.wikipedia.org Diazóniumvegyületek
Azobenzene is a photoswitchable chemical compound composed of two phenyl rings linked by a N=N double bond.It is the simplest example of an aryl azo compound.The term 'azobenzene' or simply 'azo' is often used to refer to a wide class of similar compounds.
Azo pigments are similar in chemical structure to azo dyes, but they lack solubilizing groups. [8] Many so-called azo pigments are not strictly classifiable as azo compounds since they exist as keto hydrazide tautomers, which lack the -N=N- linkage. C.I. Pigment Yellow 12, an azo pigment (also classified as a diarylide pigment).
Azo compounds are organic compounds bearing the functional group diazenyl (R−N=N−R′, in which R and R′ can be either aryl or alkyl groups).. IUPAC defines azo compounds as: "Derivatives of diazene (diimide), HN=NH, wherein both hydrogens are substituted by hydrocarbyl groups, e.g. PhN=NPh azobenzene or diphenyldiazene.", where Ph stands for phenyl group. [1]
Alizarine Yellow R is a yellow colored azo dye made by the diazo coupling reaction. It is usually commercially available as a sodium salt. In its pure form, it is a rust-colored solid. [2] It is mainly used as a pH indicator.
Notice that the coupling occurs adjacent to the hydroxy group. 3-Hydroxy-2-naphthoic acid is a precursor to many anilides, such as Naphthol AS, which are reactive toward diazonium salts to give deeply colored azo compounds. Azo coupling of 3-hydroxy-2-naphthoic acid gives many dyes as well. Heating 3-hydroxy-2-naphthoic acid in ammonia give 3 ...