Mechanistic study of the unimolecular decomposition of 1,2-dioxetanedione

The unimolecular decomposition of 1,2-dioxetanedione, the high-energy intermediate of the chemiluminescence peroxyoxalate reaction, was studied by theoretical means for the first time. Our calculations have provided results in line with the experimental data regarding this compound. 1,2-Dioxetanedione decomposes due to a step-wise biradical mechanism. In the biradical region of the decomposition path, there is a path for singlet chemiexcitation. Interactions between the singlet ground and excited states with triplet states can explain the weak unimolecular chemiluminescence of 1,2-dioxetanedione. Copyright (c) 2013 John Wiley & Sons, Ltd.