Co-Authors:
Tomer, K.B., Chemical Laboratory II, University of Copenhagen, H. C. Ørsted Institute, DK-2100 Copenhagen, Denmark, Danish National Science Foundation
Harrit, N., Chemical Laboratory II, University of Copenhagen, H. C. Ørsted Institute, DK-2100 Copenhagen, Denmark
Rosenthal, I., Chemical Laboratory II, University of Copenhagen, H. C. Ørsted Institute, DK-2100 Copenhagen, Denmark, Weizmann Institute of Science, Rehovot, Israel
Buchardt, O., Chemical Laboratory II, University of Copenhagen, H. C. Ørsted Institute, DK-2100 Copenhagen, Denmark
Kumler, P.L., Department of Chemistry, Saginaw Valley College, University Center, MI 48710, United States
Creed, D., Davy Faraday Laboratory, Royal Institution, London WIX 4BS, United Kingdom
Abstract:
The ultraviolet irradiation of 3,6-diphenylpyridazine N-oxide results mainly in formation of 3-benzoyl-5-phenylpyrazole and 2,5-diphenylfuran. By varying the temperature or the intensity of the light one of these two products could be formed preferentially. The irradiation of 1,4-diphenylphthalazine N-oxide in various solvents results in the formation of 1,3-diphenylisobenzofuran. In each case transient intermediates were detected and characterized by their uv and ir spectra. These intermediates are identified as diazo ketones and the results of the irradiation of 3,6-diphenylpyridazine N-oxide are interpreted on the basis of competing thermal and photochemical pathways for the decomposition of the intermediate diazo ketone. The formation and disappearance of this diazo ketone were studied with conventional as well as nanosecond flash photolysis; from these results we conclude that it is generated from a singlet excited state, and most likely directly from the excited state, without the formation of a transient oxaziridine, as previously believed.
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מונוכרום
הדגשת קישורים
חסימת אנימציה
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