Chemiluminescence of Organic Peroxides

Abstract

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

“…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. 21,22 was used to determine the singlet quantum yields and 9,10-dibromoanthracene (DBA, E ox p/2 ¼ 1.42 V vs. SCE), 23,24 which can act as a triplet energy acceptor due to the bromine heavy-atom effect, [1][2][3] was utilized to determine the triplet quantum yields. These quantum yields of electronically excited states formed in the decomposition of 4 are F T ¼ 1.0 AE 0.3 Â 10 À2 E mol À1 and F S ¼ 3.3 AE 0.3 Â 10 À5 E mol À1 , corresponding to a triplet to singlet ratio (F T /F S ) of about 300, similar to that commonly observed in 1,2-dioxetane decomposition.…”

“…The simplest models for chemiluminescence (CL) and bioluminescence transformations are constituted by the thermal unimolecular decomposition of 1,2-dioxetanes (1) and 1,2dioxetanones (2) and the mechanism of these transformations has been extensively studied by experimental and theoretical means. [1][2][3] Several hundreds of 1,2-dioxetane derivatives have been prepared and their properties studied, mainly the activation parameters and the singlet and triplet chemiexcitation quantum yields. Additionally, ve 1,2-dioxetanone derivatives have been synthesised and only one derivative has been studied in detail, namely 4,4-dimethyl-1,2-dioxetanone (3), whose unimolecular, as well as catalysed decomposition, has been considered by several research groups.…”

“…Additionally, ve 1,2-dioxetanone derivatives have been synthesised and only one derivative has been studied in detail, namely 4,4-dimethyl-1,2-dioxetanone (3), whose unimolecular, as well as catalysed decomposition, has been considered by several research groups. [1][2][3][4][5] More recently, we reported experimental data on the catalysed decomposition of two new 1,2-dioxetanone derivatives, spiro-adamantyl-1,2dioxetanone (4) and spiro-cyclopentyl-1,2-dioxetanone (5). 6 The unimolecular decomposition of 1,2-dioxetanes and 1,2dioxetanones leads, mainly, to the formation of triplet excited carbonyl products, with quantum yields of up to 30%, whereas the singlet excited state formation is inefficient, reaching rarely up to 1%.…”

“…6 The unimolecular decomposition of 1,2-dioxetanes and 1,2dioxetanones leads, mainly, to the formation of triplet excited carbonyl products, with quantum yields of up to 30%, whereas the singlet excited state formation is inefficient, reaching rarely up to 1%. [1][2][3][4] Peroxide derivatives with higher degree of substituents are more stable and possess higher quantum yields. 2,4,7 Two extreme pathways were suggested for this transformation; a concerted mechanism, rst proposed by Turro, 8 as well as a biradical path, initially formulated by Richardson.…”

One Century of Bioenergy in Germany: Wildcard and Advanced Technology

“…Hence, the rise of agricultural (biogas) plants had started. In 1944 an agricultural plant that produced biogas from manure and agricultural waste and residues was built by Imhoff .…”