芘在改性硅胶上的光物理研究——以芘为探针研究改性硅胶的表面特性

THE PHOTOPHYSIS OF PYRENE ON MODIFIED SILICA GEL——INVESTIGATION OF SILICA GEL SURFACE CHARACTER BY PYRENE FLUORESCENCE PROBE

研究了芘在正十碳烷氧基和三甲基硅氧基改性硅腔表面上的荧光光谱和寿命。在这二种硅胶上,激基缔合物是由基态聚积体直接受光和受激发的单分子和基态的单分子所形成、在硅胶≡Si—O—C_(10)H_(21)-n上比在硅胶≡Si—O—SiMe_3上所形成的聚积体较少。化学改性与物理改性相结合可使芘在较大的浓度范围内主要以单分子分散。激基缔合物的形成主要是由动力学过程所控制。研究了温度对芘的荧光光谱和寿命的影响。激基缔合物形成过程的活化能约为7kcal mol^(-1)。讨论了环境对单分子荧光光谱结构的影响。

Three kinds of chemical modified silica gel, Si-O-C_(10)H_(21)-n(Ⅰ), (Ⅱ)and Si-O-SiMe_3 (Ⅲ), were prepared. Fluorescence and lifetime of pyrene on these silica, gel were investigated. Exeimer emission of pyrene was formed from two pathways, excited groud state aggregate and excited monomer with groud state monomer. Groud state aggregate on silica gel Ⅲ was more than on silica gel Ⅰ in same concentration. Pyrene was dispersed as monomer in wide range coneentration when chemical modified silica gel adsorbed 1-decanol and excimer formation was controlled predominantly by dynamic process. Activated energy of excimer formation is 7 kcal mole^(-1). Effect of temperature on fluorescence and lifetime of pyrene was studied. Effect of topochemical environment on fluorescence vibrational strueture Of pyrene was discussed.