ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The unimolecular fragmentation reactions of the radical cations of diethyl, diisopropyl, dipropyl, isopropyl propyl, and di(tert-butyl) peroxide have been investigated by mass spectrometric and isotopic labeling techniques. Two competing pathways for unimolecular decomposition in the μs time regime (metastable ions) are observed: i) A combination of an α-C—C bond cleavage and a H migration gives rise to proton-bound dimers of two ketone or aldehyde molecules. ii) Ion/dipole complexes of alkyl cations and alkylperoxy radicals are generated by C-O bond cleavage. These complexes either exhibit direct losses of alkylperoxy radicals, or they rearrange via a coupled proton and H-atom transfer, this sequence of unprecedented isomerizations is completed by losses of alkyl radicals. Collisional activation experiments confirm that the ionic products of the latter process correspond to RR′C=OOH+; these ions can be regarded as protonated carbonyl oxides. In addition, we observe the elimination of alkenes leading to hydroperoxide radical cations and the expulsion of HO2⋅ radicals. The latter process implies a C—C bond formation step between the two alkyl fragments leading to higher alkyl cations.
Additional Material:
6 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19950780808
