有机化合物的光物理研究 XI. 芘在不同极性溶剂中的瞬态过程

芘是一种很好的电子转移试剂,它既可以作为电子给体,又可以作为电子受体。因此,在电子转移光化学、光物理中有不少研究文章报导。由于其较强的荧光、较高的量子产率及较长的荧光寿命,因而常被用作荧光探针,研究胶体分子及生物大分子的结构和功能等。利用紫外、红外、电子脉冲辐射和激光光解瞬态光导的测量方法研究芘与一些溶剂的相互作用以及在不同极性溶剂中的光离子化现象已有一些研究工作。本文报导芘在不同极性溶剂中的时间分辨瞬态吸收光谱的研究结果。藉对芘在不同极性溶剂中的时间分辨瞬态吸收光谱的研究,了解芘在不同极性溶剂中的瞬态反应过程,考查其与溶剂间在激光作用下的相互作用。

Photophysical Research on Organic Compounds

The transient processes of pyrene (Py) have been studied by measuring fluores-cence lifetime and nanosecond time-resolved transient absorption spectra in n-hexane, cyclohexane, acetone, and acetonitrile. The single exponential decay for pyrene-hexane and pyrene-oyclohexane systems were observed, yet the double exponential decay were shown for the pyrene-acetone and pyrene-acetonitrile systems (Table 1 of the Chinese text). In the transient absorption spectra, the absorbance of excited triplet pyrene was observed for the pyrene-acetonitrile system (Fig.2 of the Chinese text). This result clearly demonstrate that there are interaction between pyrene and acetonitrile and pyrene cation radical is formed by electron transfer from the excited singlet state of pyrene to acetonitrile. According to experimental results, the photophysical mechanism for the four systems was suggested.