Dioxetane

Dioxetanes are heterocyclic organic compounds which consist of a four-membered ring that contains two oxygen atoms and two carbon atoms. 1,2-Dioxetane is an organic peroxide with the two oxygen atoms adjacent to each other. 1,3-Dioxetane has alternating oxygen and carbon atoms.

Some dioxetanes are responsible for bioluminescence. In the 1960s biochemists came to the conclusion that these compounds had a fleeting existence in fireflies, glow-worms and other luminescent creatures. The instability of these four-membered cyclic peroxides meant that the hypothesis could not be proved. Then in 1968 the first example of a stable dioxetane was made during the course of other research at the University of Alberta in Edmonton. This first example was 3,3,4-trimethyl-1,2-dioxetane prepared as a yellow solution in benzene. When heated to 333 K, it decomposed smoothly rather than explosively as many peroxides do. Moreover, it decomposed to acetone and acetaldehyde with the emission of pale blue light.

The second example of a dioxetane was made shortly after. It was the symmetrical compound 3,3,4,4-tetramethyl-1,2-dioxetane. This could be obtained as pale yellow crystals that sublimed even when kept in the refrigerator. Benzene solutions of this compound also decomposed smoothly with the emission of blue light. By adding compounds that normally fluoresce in UV light the colour of the emitted light could be altered. Because theoretical scientists seek to understand the mechanism of light emission this second example rapidly became the most studied symmetrical compound ever. .The luminescent bangles and necklaces worn at outdoor evening events make use of a dioxetane derivative called dioxetanedione that decomposes to carbon dioxide. Other dioxetanes are used in clinical analysis where the ability to detect very faint light emission allows chemists to detect very low concentrations of body fluid constituents.