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Full-Text Articles in Social and Behavioral Sciences
The Loss Of Carbon Dioxide From Activated Perbenzoate Anions In The Gas Phase: Unimolecular Rearrangement Via Epoxidation Of The Benzene Ring, David G. Harman, Aravind Ramachandran, Michelle Gracanin, Stephen J. Blanksby
The Loss Of Carbon Dioxide From Activated Perbenzoate Anions In The Gas Phase: Unimolecular Rearrangement Via Epoxidation Of The Benzene Ring, David G. Harman, Aravind Ramachandran, Michelle Gracanin, Stephen J. Blanksby
Stephen Blanksby
The unimolecular reactivities of a range of perbenzoate anions (X−C6H5CO3-), including the perbenzoate anion itself (X = H), nitroperbenzoates (X = para-, meta-, ortho-NO2), and methoxyperbenzoates (X = para-, meta-OCH3) were investigated in the gas phase by electrospray ionization tandem mass spectrometry. The collision-induced dissociation mass spectra of these compounds reveal product ions consistent with a major loss of carbon dioxide requiring unimolecular rearrangement of the perbenzoate anion prior to fragmentation. Isotopic labeling of the perbenzoate anion supports rearrangement via an initial nucleophilic aromatic substitution at the ortho carbon of the benzene ring, while data from substituted perbenzoates indicate that …
Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby
Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby
Stephen Blanksby
α-Carboxylate radical anions are potential reactive intermediates in the free radical oxidation of biological molecules (e.g., fatty acids, peptides and proteins). We have synthesised well-defined α-carboxylate radical anions in the gas phase by UV laser photolysis of halogenated precursors in an ion-trap mass spectrometer. Reactions of isolated acetate (CH2CO 2-) and 1-carboxylatobutyl (CH3CH 2CH2CHCO2-) radical anions with dioxygen yield carbonate (CO3-) radical anions and this chemistry is shown to be a hallmark of oxidation in simple and alkyl-substituted cross-conjugated species. Previous solution phase studies have shown that Cα-radicals in peptides, formed from free radical damage, combine with dioxygen to form …