Synthesis of unstable cyclic peroxides for chemiluminescence studies

Abstract

Peróxidos cíclicos de quatro membros são intermediários de alta energia importantes em diversas transformações quimi e bioluminescentes. Especificamente, a-peroxilactonas (1,2-dioxetanonas) têm sido consideradas sistemas modelo para a eficiente bioluminescência do vaga-lume. Contudo, a preparação deste tipo de compostos altamente instáveis é extremamente difícil e, por isso, apenas alguns poucos grupos de pesquisa puderam estudar as propriedades dessas substâncias. Neste trabalho, a síntese, purificação e caracterização de três 1,2-dioxetanonas são relatadas e é apresentado um procedimento detalhado para a preparação do peróxido de difenoíla, outro importante composto-modelo para a geração química de estados eletronicamente excitados. Para a maioria destes peróxidos, a caracterização espectroscópica completa é relatada pela primeira vez.Cyclic four-membered ring peroxides are important high-energy intermediates in a variety of chemi and bioluminescence transformations. Specifically, a-peroxylactones (1,2-dioxetanones) have been considered as model systems for efficient firefly bioluminescence. However, the preparation of such highly unstable compounds is extremely difficult and, therefore, only few research groups have been able to study the properties of these substances. In this study, the synthesis, purification and characterization of three 1,2-dioxetanones are reported and a detailed procedure for the known synthesis of diphenoyl peroxide, another important model compound for the chemical generation of electronically excited states, is provided. For most of these peroxides, the complete spectroscopic characterization is reported here for the first time.Keywords: organic peroxides, diphenoyl peroxide, 1,2-dioxetanones, a-peroxylactones, chemiluminescence IntroductionThe light emission resulting from a chemical transformation is called chemiluminescence.1 Most chemiluminescent reactions 2-5 have four-membered cyclic organic peroxides as high-energy intermediates. These compounds are fundamental for the chemical generation of electronic excited states 1 and are assumed to take part also in bioluminescence reactions, such as the firefly luciferin/ luciferase system. 6,7 Many theoretical investigations have been performed, including recent studies, to contribute to the mechanistic elucidation of chemiluminescent and bioluminescent transformations. [8][9][10][11][12][13][14][15][16][17] Furthermore, some of these unstable cyclic peroxides with high energy content have been prepared, allowing the experimental mechanistic investigation of chemiluminescent reactions 8,[18][19][20] as well as the development of several applications, including the uphill energy conversion. 21 In 1969, Kopecky and Mumford 22 synthesized 3,3,4-trimethyl-1,2-dioxetane (Scheme 1, 1: R 1 = R 2 = R 3 = CH 3 , R 4 = H), the first 1,2-dioxetane (1) derivative, a compound formerly assumed to be too unstable to be isolated. Three years later, Adam and Liu 23 reported the synthesis of 3-tert-butyl-1,2-dioxetanone (Scheme 1, 2: R 1 = tert-butyl, ...

A combined theoretical and experimental study on the mechanism of spiro-adamantyl-1,2-dioxetanone decomposition

“…The relatively stable a-peroxylactone derivative, spiroadamantyl-1,2-dioxetanone (4), was synthesized according to the published procedure, puried by low-temperature recrystallization and characterized by NMR spectroscopy as reported before. 22 The kinetic assays on the decomposition of the 1,2dioxetanone derivative 4 were performed in toluene as solvent. Initially, the singlet (F S ) and triplet quantum yields (F T ) in its unimolecular decomposition were determined, using two energy acceptors which are known to possess relatively high oxidation potentials and therefore should not lead to signicant catalysed decomposition of the peroxide.…”

Solvent viscosity influence on the chemiexcitation efficiency of inter and intramolecular chemiluminescence systems

“…[44][45][46][47][48] The most difficult preparation is that of the 1,2-dioxetanone derivative 2, which had only been synthesized earlier by Adam's group; we have recently lined out detailed procedures for the synthesis of unstable cyclic peroxides including this derivative 2. 46,48,49 It should be mentioned here that only a few research groups have been able to study the chemiluminescence properties of 1,2-dioxetanone derivatives due to their difficult preparation and extremely low stability. 46,48,49 It should be mentioned here that only a few research groups have been able to study the chemiluminescence properties of 1,2-dioxetanone derivatives due to their difficult preparation and extremely low stability.…”

“…46,48,49 The peroxide stock solutions were stored at low temperature (−80°C) and kept at −78°C during the experiments. Diphenyl ether was stirred in the presence of MgSO 4 for 6 hours, after filtration it was distilled under reduced pressure and stored over 4 Å molecular sieves.…”

Four‐membered cyclic peroxides: Carriers of chemical energy

“…Glassware should be clean and free from metals, especially iron. Treatment of the glassware with a saturated EDTA solution is recommended, followed by carefully washing with deionized water. Depending on the 1,2‐dioxetanone, monitoring of reaction progress by TLC is not possible because of its decomposition on silica gel even at low temperature …”