Improvement of Fluorescence Characteristics of Coumarins: Syntheses and Fluorescence Properties of 6-Methoxycoumarin and Benzocoumarin Derivatives as Novel Fluorophores Emitting in the Longer Wavelength Region and Their Application to Analytical Reagents
作者:Chiyomi Murata、Toshinobu Masuda、Yasuko Kamochi、Kenichiro Todoroki、Hideyuki Yoshida、Hitoshi Nohta、Masatoshi Yamaguchi、Akira Takadate
DOI:10.1248/cpb.53.750
日期:——
To improve the fluorescence characteristics, especially emission wavelength, of coumarins, various 3-substituted-6-methoxycoumarin derivatives were synthesized, and then benzocoumarin derivatives were also synthesized in expectation of the shift to the longer wavelength region by the extension of the conjugated system. Their fluorescence properties were investigated spectrophotometrically in acetonitrile and evaluated from the viewpoint of the intramolecular charge transfer (ICT) between push- and pull-substituents in the ground and the excited states. Among them, benzocoumarin derivatives especially fluoresced in the longer wavelength around 540 nm with remarkably large Stokes shifts beyond 10000 cm−1. Using such fluorophores, some novel fluorescence derivatization reagents for carboxylic acids, alcohols, phenols, and amines were preliminarily prepared as an example, and their derivatized products were also found to fluoresce in the longer wavelength region with large Stokes shifts.
为了改善香豆素的荧光特性,特别是发射波长,合成了多种3取代-6-甲氧基香豆素衍生物,随后又合成了苯香豆素衍生物,期待通过延长共轭体系实现向长波长区域的转移。采用光谱法在乙腈中研究了它们的荧光特性,并从基态和激发态中推送和拉动取代基之间的分子内电荷转移(ICT)角度进行了评估。在这些衍生物中,苯香豆素衍生物特别在540 nm附近的长波长范围内具有显著的荧光,斯托克斯位移超过10000 cm−1。利用这些荧光基团,初步制备了一些新型的荧光衍生化试剂用于羧酸、醇、酚和胺,发现其衍生化产物在长波长区域也具有显著的荧光和较大的斯托克斯位移。