Unstable dioxetanones

Dioxetanones are too unstable ever to be isolable when directly attached to the fluorescent donor, but the related dioxetans can usually be characterised. Some have already been discussed (p. 63) but direct relation to the acridan esters would provide the best connection with the luciferins. Even dioxetans present stability problems. For example, treatment of (25) with singlet oxygen gave a dioxetan [39] with a half life of 8 min. at 25 C, decomposing with a quantum yield of 0.25. This decomposition could be followed by N.M.R. 

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