Peroxy-radical-mediated chemiluminescence: mechanistic diversity and fundamentals for antioxidant assay

Herein, we give a retrospective overview and analyze recent developments in the field of chemiluminescence derived from organic oxidation processes (so called oxychemiluminescence), most prominently, mediated by peroxy radicals. As evidenced from the presented analysis, the diversities of the reaction and the excited-state-generation mechanisms are governed mainly by a diverse chemical nature of substrates being oxidized. The notable oxychemiluminescence cases, which involve peroxy radicals as key reactive species, refer to oxidation of saturated and unsaturated hydrocarbons, polymers, lipids and proteins. The general feature of the considered chemiluminescence processes pertains to a formation of high-energy cyclic intermediates (tetroxides and/or dioxetanes), whose cleavage yields electronically excited products. The considered modes of the chemiluminescence enhancement encompass the energytransfer and the electron-transfer mechanisms. Most prominent application of the discussed oxychemiluminescence phenomenon resides in a versatile chemiluminescent assay to monitor antioxidants (both their concentration and reactivity) in chemical and biological media.