Resonance structures of a diazo compound
Diazo compounds are a group of organic compounds in which two nitrogen atoms are directly linked together and one of the nitrogen atoms is attached to a carbon atom. The two nitrogen atoms form the end of a chain. The general formula for diazo compounds is R2 C = N2. The simplest example of a diazo compound is diazomethane, H2C = N2. The diazo compound as a whole is electrically neutral, but the electron structure of the diazo group causes the central nitrogen atom to carry a positive charge, the terminal nitrogen and the carbon atom share the negative charge. Some of the most stable diazo compounds are α-diazoketones and α-diazoesters, because then the negative charge of the carbon atom can be de-localized to the carbonyl group. In contrast, most alkyl-diazate compounds are explosive.
Diazole compounds are used as starting materials for carbenes, which arise from thermolysis or photolysis, for example in the Wolff rearrangement. Diazate compounds are also used in transition metal-catalyzed cyclopropane formation. The synthesis of tranylcypromine is an example: the sodium salt of benzaldehyde tosylhydrazone is converted to a rhodium-containing metal carbene via a diazo intermediate:
A commercially important compound is ethyldiazoacetate (N2CHCOO-Et).
A group containing the diazo compounds isomeric compounds is formed by the diazirins in which one carbon and two nitrogen atoms in a triple are linked together. Also see
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