1.2- Dioxetanones peroxyoxalates

The brilliant emissions resulting from the oxidation of certain oxalic acid derivatives, especially in the presence of a variety of fluorophores, are the bases of the most active area of current interest in CL. This group of chemiluminescent reactions has been classified as peroxyoxalate chemistry because it derives from the excited states formed by the decomposition of cyclic peroxides of oxalic acid derivatives called dioxetanes, dioxetanones, and dioxetanediones. 

Intensive studies in the field of mechanistic CL by several research groups have resulted in the description of a large variety of peroxides which, in the presence of appropriate activators, show decomposition in an activated CL process and might involve the CIEEL mechanism . Even before the formulation of the CIEEL mechanism, Rauhut s research group obtained evidence of the involvement of electron-transfer processes in the excitation step of the peroxyoxalate CL. Results obtained in the activated CL of diphe-noyl peroxide (4) led to the formulation of this chemiexcitation mechanism , and several 1,2-dioxetanones (a-peroxylactones), such as 3,3-dimethyl-l,2-dioxetanone (9) and the first a-peroxylactone synthesized, 3-ierr-butyl-l,2-dioxetanone (14), have been shown to possess similar CL properties, compatible with the CIEEL mechanism Furthermore, the CL properties of secondary peroxyesters, such as 1-phenethylperoxy acetate (15) , peroxylates (16) , o-xylylene peroxide (17) , malonyl peroxides... 

From these results, the most likely key intermediate that interacts with fluorophores is dioxetanone (II) still bearing the eliminating group rather than dioxetanedione (I) in this system. Recently, the six-membered ring was suggested by Lee et aW and B. Rechard et al reported that the key intermediate was a dioxetanedione in the certain peroxyoxalate chemiluminescence reactions. However, we believe that the results obtained in the present study can be applied to the general peroxyoxalate chemiluminescence. 

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