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

摘要

The chemiluminescence of cyclic peroxidesnactivated by oxidizable fluorescent dyes is an example ofnchemically initiated electron exchange luminescence (CIEEL),nwhich has been used also to explain the efficient bioluminescencenof fireflies. Diphenoyl peroxide and dimethyl-n1,2-dioxetanone were used as model compounds for thendevelopment of this CIEEL mechanism. However, thenchemiexcitation efficiency of diphenoyl peroxide was foundnto be much lower than originally described. In this work, wenredetermine the chemiexcitation quantum efficiency ofndimethyl-1,2-dioxetanone, a more adequate model for fireflynbioluminescence, and found a singlet quantum yield (ΦS) of 0.1%, a value at least 2 orders of magnitude lower than previouslynreported. Furthermore, we synthesized two other 1,2-dioxetanone derivatives and confirm the low chemiexcitation efficiency (ΦSn< 0.1%) of the intermolecular CIEEL-activated decomposition of this class of cyclic peroxides. These results are compared withnother chemiluminescent reactions, supporting the general trend that intermolecular CIEEL systems are much less efficient inngenerating singlet excited states than analogous intramolecular processes (ΦS ≈ 50%), with the notable exception of thenperoxyoxalate reaction (ΦS ≈ 60%).