新型染料敏化体系──荧光素染料碘鎓盐的光谱研究

NOVEL DYE PHOTOSENSITIZATION SYSTEMS---SPECTROSCOPIC STUDY OF FLUORESCEIN DYE IODONIUM SALTS

本文合成了一系列荧光素类染料碘盐，并研究了其光谱及光化学性质。结果表明，通过改变结构，可改变它们的吸收光谱。提出可用Ｉ＿Ⅰ／Ｉ＿Ⅱ值来表征这类化合物在溶剂中的相对解离程度。随溶剂极性，染料母核Ｃ－６位周围（Ｃ－７，Ｃ－８位）空间位阻增大和染料母核上吸电子取代基增多，Ｉ＿Ⅰ／Ｉ＿Ⅱ值增大，它们的相对解离程度升高，光谱性质显著变化，光化学反应速度下降。在极性和非极性溶剂中，浓度对光谱和光化学性质具有不同的影响。显示这类化合物除可用作可见光敏化聚合和交联的光引发体系外，还可能用作探针探测周围环境的变化。

In this work,a series of fluorescein dye idonium salts were synthesized and their spectral and photochemical properties were studied.Results show that their spectral propertiescan be changed through the variation of their own structures. I_Ⅰ/I_Ⅱ was proposed to compare the relative degree of dissociation of these compounds in solvents. With increasing thesolvent polarity,the steric hindrance around the C- 6 position and the number of eletronwithdrawing groups, the I_Ⅰ/I_Ⅱvalue increases,so does the relative degree of dissociation.Followingly, the spectral properties change significantly and the rate of photoreaction decreases. The concentration of dye iodonium salts has different effects on their spectral andphotochemical properties in polar and nonpolar solvents respectively. It is shown that thesecompounds may not only be used as photoinitiators for photopolymerization and photocrosslinking,but also as probes for studing the enviromental properties.