Dioxetanes properties

The most remarkable property of both dioxetanes and dioxetanones is their ability to chemiluminesce when heated to their decomposition point. In general this behavior can be summarized as in Scheme 15 (79MI51502). Both 1,2-dioxetanes and l,2-dioxetan-3-ones (a -peroxylactones) give more triplet than singlet ketones (< x = 2 25 00 (77AHC(21)437))... 

Dimole absorption and emission, 247 Dioxetane formation, 253 Donor-acceptor energy levels, 201 property, energies of, 289 Dipole-dipole resonance energy transfer, 192, 193... 

There is a high interest to know the structural features which endow the thermal stability of dioxetanes since this property makes the dioxetane easy to handle and, if accompanied with high chemiluminescence, usable as enzyme label in bioanalytical, clinical application [111]. In this field,... 

A unique property of dioxetanes is to decompose thermally to electronically excited carbonyl products with subsequent emission of blue light... 

CIEEL) pathway has been shown to be capable of generating high yields of chemiluminescence from certain peroxides (Schuster, 1979 Schuster et al., 1979). CIEEL offers an explanation for the unusual properties of these dioxetanes. 

To spot the dioxetanes, monitoring the eluate by TLC, utilizing their peroxidic and/or chemiluminescent properties, is quite convenient. In most instances, a TLC plate soaked with an aqueous KI solution will do but for very resistant cases such as diadamantylidene-l,2-dioxetane (9), ferrous sulfate-ammonium thiocyanate and concentrated hydrochloric acid will not fail. In the case of detection via chemiluminescence, the TLC plate is sprayed with a 9,10-dibromoanthracene DBA) or 9,10-diphenylanthracene (DPA) solution and heated in the dark. The dioxetane spot glows bright blue. 

Undoubtedly, the most characteristic property of 1,2-dioxetanes and a-peroxylactones is the fact that they emit light on thermal decomposition. Since in liquid media in the presence of molecular oxygen triplet excited states are efficiently quenched, the observed direct chemiluminescence is ascribed to the fluorescence of the carbonyl product. This fluorescence occurs usually at 420 10nm and corresponds to n n excitation.The shortest wavelength emission has probably been observed for the indole-1,2-dioxetane (17) that occurs at 320 nm. ... 

As already pointed out on several occasions, the unique property of dioxetanes is to generate electronically excited states on thermolysis, which then manifest themselves by light emission (Eq. 28). The total yield of excited states (Eq. 33), that is, the sum of the singlet excitation yield (0 ), triplet excitation yield (0 ), and the spin-state selectivity (Eq. 34), that is, the ratio of the triplet and singlet excitation yields, are excitation parameters that characterize a particular dioxetane. 

V. HEAVY ATOM SUBSTITUTION. The series of bromine-substituted 1,2-dioxetanes, shown in Eq. 65, were studied to assess whether such a heavy atom influences the excitation parameters through its spin-orbit coupling property. Qearly, the effect is dramatic on both the total efficiency and the spin-... 

Adam W, Baader WJ, Effects of methylation on the thermal stability and chemiluminescence properties of 1,2-dioxetanes. J Am Chem Soc 1985 107 410-6. 

Birks has recently prepared a monograph on chemluminescence and photochemical reaction detection in chromatography which is likely to be of particular interest to analytical chemists. Few papers on chemiluminescence have appeared in the mainstream chemical literature. A significant exception is a theoretical treatment of the mechanism of the chemiluminescent decompositon of 1,2-dioxetanes . A series of phenyl N-alkylacridinium 9-carboxylates have been synthesised and their chemiluminescent properties evaluated. ... 

Edwards B, Sparks A, Voyta JC, Bronstein I. Unusual luminescent properties of odd- and even-substituted naphthyl-derivatized dioxetanes. J Biolumin Chemilumin 1990 5 1-4. 

Fig. 38. Chemiluminescence properties of the phenolic anions of two substituted adamantyl naphthyl dioxetanes. The emission wavelength and half-life of compound (a) are 550 nm and 23 min, respectively, while the corresponding values for compound (b) are 459 nm and 9 sec. These data are taken from Edwards et at. (El).

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