POLYENE 2(1)AG AND 1(1)BU STATES AND THE PHOTOCHEMISTRY OF PREVITAMIN-D3

被引:42
作者
DAUBEN, WG [1 ]
DISANAYAKA, B [1 ]
FUNHOFF, DJH [1 ]
KOHLER, BE [1 ]
SCHILKE, DE [1 ]
ZHOU, BL [1 ]
机构
[1] UNIV CALIF RIVERSIDE,DEPT CHEM,RIVERSIDE,CA 92521
关键词
D O I
10.1021/ja00022a025
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The quantum yields of the photoproducts from previtamin D3 were measured at different wavelengths with monochromatic irradiation. While the quantum yield for the cis-trans isomerization decreases with increasing wavelength near 303 nm, the ones for formation of the ring-closure products increase dramatically. This increase in photocyclization yield with decreasing photon energy is attributed to the involvement of both the 1B and 2A excited states of previtamin D3. This hypothesis is supported by measurements of the previtamin D3 fluorescence spectrum, fluorescence lifetime, wavelength dependence of the fluorescence quantum yield, and temperature dependence of fluorescence intensity. All of these data are integrated into a potential energy surface diagram that is consistent with both the photochemical and spectroscopic behavior.
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页码:8367 / 8374
页数:8
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