Thermochemistry of 1,2-dioxetane and its methylated derivatives. Estimate of activation parameters
01 Nov 1970-Journal of the American Chemical Society (American Chemical Society)-Vol. 92, Iss: 22, pp 6553-6557
About: This article is published in Journal of the American Chemical Society.The article was published on 1970-11-01. It has received 90 citations till now. The article focuses on the topics: Thermochemistry.
Citations
More filters
TL;DR: In this paper, a mechanism for thermal production of excited states is discussed, where electron transfer from an easily oxidized donor to a suitable organic peroxide followed by oxygen-oxygen bond cleavage generates radical ion intermediates.
Abstract: : A mechanism for thermal production of excited states is discussed. Electron transfer from an easily oxidized donor to a suitable organic peroxide followed by oxygen-oxygen bond cleavage generates radical ion intermediates. Subsequent chemical reaction followed by charge annihilation generates electronically excitated state products. This sequence of reactions is called chemically initiated electron-exchange luminescence and is shown to be operating for diphenoyl peroxide, 1-phenylethylperoxy acetate, dimethyldioxeta-none, and 1,4-diphenyl-2,3-benzodioxin (0-xylylene peroxide). (Author)
339 citations
TL;DR: A molecular-orbital perspective is adopted to explain the chemistry behind chemiexcitation in both chemi- and bioluminescence and should be an inspiration to human design of new molecular systems expressing unique light-emitting properties.
Abstract: Bioluminescence is a phenomenon that has fascinated mankind for centuries. Today the phenomenon and its sibling, chemiluminescence, have impacted society with a number of useful applications in fields like analytical chemistry and medicine, just to mention two. In this review, a molecular-orbital perspective is adopted to explain the chemistry behind chemiexcitation in both chemi- and bioluminescence. First, the uncatalyzed thermal dissociation of 1,2-dioxetane is presented and analyzed to explain, for example, the preference for triplet excited product states and increased yield with larger nonreactive substituents. The catalyzed fragmentation reaction and related details are then exemplified with substituted 1,2-dioxetanone species. In particular, the preference for singlet excited product states in that case is explained. The review also examines the diversity of specific solutions both in Nature and in artificial systems and the difficulties in identifying the emitting species and unraveling the color...
227 citations
158 citations
TL;DR: In this paper, it was shown that no oxidation of the substrates examined was found to occur in the absence of ketone and the possibility that formation of dioxathiirane intermediates (XXII) occurs following a side pathway in the reaction of Caroate with sulfoxides (which produces sulfones in high yield) has been explored.
Abstract: — Kinetics and 18O-labeling studies have provided evidence for the involvement of dioxirane intermediates (V) in the ketone-catalysed decomposition of peroxomonosulfate (Caroate) HSO;. Reaction rates depend on ketone structure. In competition with catalysis of peroxide decomposition, the dioxirane intermediate is capable of oxidizing several organic and inorganic substrates. Thus, cis- and rrans-cinnammic acids could be converted stereospecifically into the corresponding epoxides. Also, oxidation of phenylpropiolic acid, a substrate which is representative of weakly nucleophilic alkynes, could be carried out using the Caroatehetone oxidizing system. Under the conditions adopted, no oxidation of the substrates examined was found to occur in the absence of ketone. The possibility that formation of dioxathiirane intermediates (XXII) occurs following a side pathway in the reaction of Caroate with sulfoxides (which produces sulfones in high yield) has been explored. Preliminary experiments using 18O-labeling of p-tolyl phenylsulfoxide, however. failed to support this hypothesis. pointing out the need for further detailed studies.
142 citations
TL;DR: A revision of the most typical examples used to illustrate the existence of secondary orbital interactions (SOI) has been achieved, but analysis indicates that no conclusive evidence can be obtained from these cases.
Abstract: A revision of the most typical examples used to illustrate the existence of secondary orbital interactions (SOI) has been achieved. However, our analysis indicates that no conclusive evidence can be obtained from these cases. All five examples proposed by Woodward and Hoffmann in The Conservation of Orbital Symmetry have been revisited. A combination of well-known mechanisms (such as solvent effects, steric interactions, hydrogen bonds, electrostatic forces, and others) can be invoked instead to justify the endo/exo selectivity of Diels−Alder reactions.
133 citations