Revision of Singlet Quantum Yields in the Catalyzed Decomposition of Cyclic Peroxides

• Published in: Journal of organic chemistry 2012-12, Vol.77 (23), p.10537-10544
• Main Authors: Almeida de Oliveira, Marcelo, Bartoloni, Fernando Heering, Augusto, Felipe Alberto, Ciscato, Luiz Francisco Monteiro Leite, Bastos, Erick Leite, Baader, Wilhelm Josef
• Format: Article
• Language: English
• Subjects: Applied sciences; Chemical industry and chemicals; Chemiluminescence; Chemistry; Dyes, pigments; Exact sciences and technology; General and physical chemistry; Industrial chemicals; Kinetics and mechanisms; Organic chemistry; Reactivity and mechanisms
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo301309v

The chemiluminescence of cyclic peroxides activated by oxidizable fluorescent dyes is an example of chemically initiated electron exchange luminescence (CIEEL), which has been used also to explain the efficient bioluminescence of fireflies. Diphenoyl peroxide and dimethyl-1,2-dioxetanone were used as model compounds for the development of this CIEEL mechanism. However, the chemiexcitation efficiency of diphenoyl peroxide was found to be much lower than originally described. In this work, we redetermine the chemiexcitation quantum efficiency of dimethyl-1,2-dioxetanone, a more adequate model for firefly bioluminescence, and found a singlet quantum yield (ΦS) of 0.1%, a value at least 2 orders of magnitude lower than previously reported. Furthermore, we synthesized two other 1,2-dioxetanone derivatives and confirm the low chemiexcitation efficiency (ΦS < 0.1%) of the intermolecular CIEEL-activated decomposition of this class of cyclic peroxides. These results are compared with other chemiluminescent reactions, supporting the general trend that intermolecular CIEEL systems are much less efficient in generating singlet excited states than analogous intramolecular processes (ΦS ≈ 50%), with the notable exception of the peroxyoxalate reaction (ΦS ≈ 60%).