Abstract

We studied the photophysical processes of halogenated fluorescein derivatives (eosin (E), erythrosine (ER), and Rose Bengal (RB)) in aqueous micellar solutions using dynamic light scattering and stationary and time-resolved fluorescence spectroscopy. The introduction of dye molecules into reverse AOT micelles causes an increase in their hydrodynamic radii R_h. The kinetics of fluorescence of the studied dye molecules in reverse micelles was investigated. The average time \(\langle \tau \rangle \) of the excited state decreases with increasing R_h for eosin, erythrosine, and Rose Bengal, which is associated with an increase in the mobility of water molecules and a weakening of the effect of geometric limitation of dye molecules. The degrees of fluorescence anisotropy r of dye molecules in reverse micelles were measured; the r values in micellar systems are greater than in aqueous solutions and decrease with increasing R_h. For the studied dye molecules in micellar systems, the rotational correlation time θ was determined, which decreases for all studied dyes with increasing R_h, which indicates a decrease in the microviscosity of a limited aqueous medium inside the micelle. It is found that θ_E > θ_ER > θ_RB; that is, the effect of the internal heavy atom appears in the value of the rotational correlation time.

中文翻译：

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阴离子反向胶束中卤代荧光素衍生物分子的光物理过程

摘要

我们使用动态光散射以及固定和时间分辨荧光光谱技术研究了胶束水溶液中卤代荧光素衍生物（曙红（E），赤藓红（ER）和玫瑰红（RB））的光物理过程。将染料分子引入反向AOT胶束中会导致其流体动力学半径R _h增大。研究了反胶束中所研究染料分子的荧光动力学。激发态的平均时间\（\ langle \ tau \ rangle \）随着R _h的增加而减小用于曙红，赤藓红和玫瑰红，这与水分子的迁移率增加和染料分子的几何限制作用减弱有关。测量了反胶束中染料分子的荧光各向异性度r；胶束系统中的r值大于水溶液中的r值，并随R _h的增加而减小。对于研究的胶束系统中的染料分子，确定了旋转相关时间θ，对于所有研究的染料，其旋转相关时间θ随R _h的增加而减小，这表明胶束内部有限水性介质的微粘度降低。发现_θE  > _θER> _θRB ; 即，内部重原子的作用出现在旋转相关时间的值中。