ISSN:
0009-2940
Schlagwort(e):
Carbonyl oxides
;
Quinone oxides
;
Dioxiranes
;
Substituent effects
;
Matrix isolation
;
Chemistry
;
Inorganic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Triplet 4-oxocyclohexadienylidenes 6, matrix-isolated in Ar/ 2% O2 at 10 K, react with triplet O2 on annealing the matrix. Primary reaction products are quinone oxides 4, which have been characterized by IR and UV/Vis spectrometry. They are very photolabile; long-wavelength irradiation converts them into spiro-dioxiranes 5, which in turn yield lactones 10 upon irradiation with visible light. Experimental data have been obtained for quinone oxides 4a-g; additionally, ground-state properties and UV/Vis absorptions of quinone oxides 4a,b and 4e-1 have been calculated by the MINDO-3/UHF and CNDO/S methods. Since the theoretical and experimental maxima of the π → π* transitions are in good agreement, we conclude that our semiempirical calculations give an adequate picture of quinone oxides 4 which may best be described as dipolar diradicals.
Zusätzliches Material:
3 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/cber.19921250811
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