荧光素衍生物在TiO_2胶体中的光物理性质研究

Photophysical Properties of Fluorescein Derivatives on TiO_2 Colloid

测定了以荧光素为光敏剂的电子给体 -受体二元化合物荧光素蒽醌甲酯 (FL AQ)及模型化合物荧光素丁酯(FL4)在溶液中和在二氧化钛 (TiO2 )胶体中的吸收光谱、荧光光谱、荧光寿命等 .发现荧光素蒽醌甲酯与荧光素丁酯均可通过酚羟基较好地吸附在TiO2 胶体上 .从吸收光谱可得 ,FL4与TiO2 形成表面络合物的表观结合常数 (Kapp)大约为 35 90mol-1·L ,结合率 (α)为 0 86 ;FL AQ与TiO2 形成表面络合物的Kapp大约为 30 6 0mol-1·L ,α为 0 84.同时通过ESR光谱讨论了光诱导电子注入机制 .

The interactions of the model compound (FL4) or diad (FL-AQ) composed of fluorescein and 2-methyl-anthraquinone and TiO2 colloid have been examined by absorption, fluorescence spectroscopy and fluorescence lifetime. This diad (FL-AQ) or model compound (FL4) is adsorbed on TiO2 colloid, through,the phenolic function of the fluorescein moiety. The apparent association constant (K-app) of FL4/TiO2 obtained from the absorption spectra is ca. 3590 mol(-1) . L. The K-app of FL - AQ/TiO2 is ca. 3060 mol(-1) . L. The degree of association ( a) between TiO2 and FL4 is ca. 0.86. The degree of association (a) between TiO2 and FL-AQ is ca. 0.84. The mechanism of the photoinduced electron injection was also discussed through ESR spectra.