Chemiluminescence Mechanism of Monoacylhydrazides

Although direct evidence is lacking, White [80] has made a very good case for the intermediacy of the acyl anion. In contrast to the cycUc hy dr azides, substitution on the nitrogen (of the hydrazide group) does not seriously affect chemiluminescence. 

A mechanism can be written which applies to any hydrazide with free NH-groups  

Much of the evidence for this route came from the initially surprising oberservation that acridine 9-carboxylic acid hydrazide gave not the excited carboxylate, but emission from acridone. Strong support for the acyl anion route is obtained from the fact that 9-formyl acridine in strong base is highly chemiluminescent [80]. 

The formation of excited acridone can be explained by one of three mechanisms  

The intermediate 9-acridinyl peroxide may react by dimerisation or by a route related to that of the Grignard chemiluminescence (p. 28). 

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