Spectroscopy and photophysics of 4-and 7-hydroxycoumarins and their thione analogs

被引：136

作者：

de Melo, JS ^{[1
]}

Fernandes, PF ^{[1
]}

机构：

[1] Univ Coimbra, Dept Chem, P-3004535 Coimbra, Portugal

来源：

JOURNAL OF MOLECULAR STRUCTURE | 2001年 / 565卷

关键词：

coumarins; photophysics; singlet state; triplet state; fluorescence; phosphorescence;

D O I：

10.1016/S0022-2860(01)00458-6

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Acid-base equilibria were studied for 4-hydroxycoumarin, 7-hydroxy-4-methylcoumarin and their thione derivatives in different media for their ground and lowest energy singlet and triplet excited states. The ethoxylated and/or methoxylated derivatives were also investigated. Characterization involves fluorescence spectra, quantum yields, lifetimes, phosphorescence spectra, lifetimes, and triplet-triplet absorption spectra. From their pK(a) values it was found that 4 and 7-hydroxycoumarins are more acidic in their lowest excited singlet states than in So. The origin and character of the lowest singlet and triplet excited states is discussed. (C) 2001 Elsevier Science B.V. All rights reserved.

引用

页码：69 / 78

页数：10

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