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014
Dimethyl peroxide radical cation: A new theoretical and experimental approach to the C2H6O.+ potential energy surface

C. A. Schalley, A. Fiedler, G. Hornung, R. Wesendrup, D. Schr”öder, H. Schwarz – 1997

The structure and the unimolecular fragmentations of the metastable dimethyl peroxide radical cation have been investigated by mass spectrometric and isotopic labeling methods as well as high-level ab initio calculations. In line with the theoretical results, neutralization-reionization and charge reversal experiments suggest that ionized dimethyl peroxide bears a CH3OOCH3.+ connectivity. In the cation the O-O bond dissociation energy is larger than that of the neutral counterpart; in contrast, the C-O bond strength is slightly and that of the C-H bond significantly reduced upon ionization. These energetic changes upon one-electron oxidation of CH3OOCH3 are also reflected in the NR and CR mass spectra of CH3OOCH3.+. Further, for metastable CH3OOCH3.+ two major fragmentation pathways are observed: 1) Loss of a hydrogen atom by cleavage of a C-H bond is associated with a skeletal reorganization, which gives rise to a proton-bound formaldehyde dimer. 2) The expulsion of a CH3O. radical leads to protonated formaldehyde in a surprisingly specific double hydrogen transfer involving a [CH3OH/CH2O](.+) ion/dipole complex as central intermediate; this complex also accounts for other minor fragmentation channels. The structures of intermediates and transition states are calculated with the BECKE 3LYP density-functional method employing a 6-311++G** basis.

Title
014
Dimethyl peroxide radical cation: A new theoretical and experimental approach to the C2H6O.+ potential energy surface
Author
C. A. Schalley, A. Fiedler, G. Hornung, R. Wesendrup, D. Schr”öder, H. Schwarz
Date
1997-04-02
Identifier
DOI 10.1002/chem.19970030420
Source(s)
Citation
Chem. Eur. J. 1997, 3, 626-638
Type
Text