Bioluminescence of the Firefly. Key Steps in the Formation of the Electronically Excited State for Model Systems.
ILLINOIS UNIV AT URBANA-CHAMPAIGN DEPT OF CHEMISTRY
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The chemical mechanism for formation of electronically excited state molecules from the thermal reaction of dimethyldioxetanone was probed. Light production in the presence of certain easily oxidized aromatic hydrocarbons was found not to conform to the classical mechanistic schemes for chemiexcitation. Detailed investigation of the dioxetanone system revealed light formation by the recently discovered chemically initiated electron exchange process. This result is extrapolated to bioluminescent systems. In particular, the key high energy molecule involved in firefly luminescence, which has been identified as a dioxetanone, is postulated to form excited states as a result of intramolecular electron transfer from the phenoxythiazole moiety to the dioxetanone. Subsequent rapid decarboxylation results in direct formation of an excited singlet state of the emitting amide. Author