THE PHOTOCHEMISTRY OF DMAPP IN SOLUTION

DMAPP is one of most stable aryl pentazolsthat initially synthesized by Huisgen and coworkers¹. Anion cyclopentazolate was formed in the gas phase from DMAPP in laser desorption ionization experiment in gas phase². Attempts to repeat this reaction thermally in the bulk have been unsuccessful ³. In solution the energy supplied to DMAPP by vacuum UV irradiation (193nm) would be sufficient to cleave the bond and to produce anion cyclopentazolate.

This study focuses on photochemistry of para-dimethylaminophenylpentazole (DMAPP) in acetonitrile (MeCN) and dichloromethane (DCM) solutions when UV and VUV sources were used. One of the goals was to cleave photochemicaly CN bond in DMAPP and to derive all-nitrogen anion cyclopentazolate. In MeCN solutions many products were found, traceable to a nitrene intermediate for both UV and VUV photolysis. UV photolysis of DCM solutions resulted withazideonly. In the VUV the DCM solution yields products containing chlorine atoms, due to partial photolysis of DCM producing chlorine-containing radicals.

Figure 1 summarizes possible photochemical routes that explain experimental observations.

Figure 1.Current hypothesis about the photochemistry of DMAPP.

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