ISSN:
1434-193X
Schlagwort(e):
Neutralization-reionization mass spectrometry
;
Density functional theory
;
Oxyallyl
;
Ketocarbenes
;
Methoxy vinylidene
;
Chemistry
;
General Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Five different anionic [C3, H4, O]·- isomers, i.e. the radical anions of acrolein, acetyl carbene, formyl methyl carbene, methoxy vinylidene, and oxyallyl are generated in an ion beam mass spectrometer and subjected to neutralization-reionization (NR) mass spectrometric experiments including neutral and ion decomposition difference (NIDD) mass spectrometry; the latter allows for the examination of the neutrals′ unimolecular reactivity. Further, the anionic, the singlet and triplet neutral, and the cationic [C3, H4, O]·-/0/·+ potential-energy surfaces are calculated at the B3LYP-6-311++G(d, p) level of theory. For some species, notably the singlet state of oxyallyl, the theoretical treatment is complemented by G2, CASSCF, and MR-CI calculations. Theory and experiment are in good agreement in that at the neutral stage (i) acrolein does not react within the μsec timescale, (ii) acetyl and formyl methyl carbenes isomerize to methyl ketene, (iii) methoxy vinylidene rearranges to methoxy acetylene, (iv) singlet 1A1 oxyallyl undergoes ring closure to cyclopropanone, and (v) triplet 3B2 oxyallyl may have a lifetime sufficient to survive a NR experiment.
Materialart:
Digitale Medien
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