Chemiluminescence of Dimethyldioxetanone. Unimolecular Generation of Excited Singlet and Triplet Acetone. Chemically Initiated Electron-Exchange Luminescence, the Primary Light Generating Reaction

Article abstract of DOI:10.1021/ja00521a049

Dimethyldioxetanone (2a) undergoes two distinct thermal reactions which generate electronically excited states.The unimolecular decomposition of 2a at 30.0 deg C produces excited singlet and triplet acetone, with efficiencies of 0.1 and 1.5percent, respectively.The composite activation energy for formation of singlet acetone is 3-4 kcal mol^-1 greater than the activation energy for the thermal disappearance of 2a.This result is interpreted in terms of two parallel competitive pathways for dioxetanone decomposition, the more highly activated one of which leads to excited acetone.The addition of easily oxidized aromatic hydrocarbons or amines catalyzes the chemiluminescence of 2a.The magnitude of the catalytic rate constant and the efficiency of light production are correlated with the one electron oxidation potential of the hydrocarbon.Under these conditions, the chemiluminescence results from a chemically initiated electron-exchange luminescence path.