Lewis-acid-catalyzed photodimerization of coumarins and N-methyl-2-quinolone

被引：25

作者：

Goerner, Helmut ^{[1
]}

Wolff, Thomas ^{[2
]}

机构：

[1] Max Planck Inst Bioanorgan Chem, Mulheim, Germany

[2] Tech Univ Dresden, Dresden, Germany

来源：

PHOTOCHEMISTRY AND PHOTOBIOLOGY | 2008年 / 84卷 / 05期

关键词：

D O I：

10.1111/j.1751-1097.2008.00339.x

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

The BF(3)-catalyzed photodimerization of parent coumarin (1), three 6-alkylcoumarins (2-4) and N-methyl-2-quinolone (5) in dichloromethane was studied by time-resolved UV-vis spectroscopy. The lowest triplet state properties in the absence and presence of BF(3) were outlined, in particular the effect of self-quenching which initiates dimerization. The quantum yield of intersystem crossing (Phi(isc)) of 1-4 increases with BF(3) concentration, approaching Phi(isc) = 0.3. Phi(isc) and the relative quantum yield of dimerization go along, thereby favoring an overall triplet mechanism in both the direct and BF(3)-catalyzed photodimerization. The product ratio of 5 changes strongly with the BF(3) concentration from 100% anti-hh for the free quinolone to 100% syn-ht for the 1:1 complex.

引用

页码：1224 / 1230

页数：7

共 31 条

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