苯环上氯原子的不同取代位置对四苯基锌卟啉-酪氨酸光物理性质的影响

Effect of Different Chlorine Substituted Positions on the Photophysical Property of Zinc(Ⅱ) Tetraphenylporphyrin-tyrosine

稳态紫外光谱、荧光光谱和时间分辨荧光光谱显示 ,苯环上氯原子的不同位置对氯苯基锌卟啉 -酪氨酸的光物理性质有很大影响 .紫外吸收光谱中 ,邻、间和对氯取代的 3个化合物都具有典型的 Soret带和 Q带 .其中 Soret带位于 42 3 nm处 ,Q( 0 ,0 )和 Q( 0 ,1 )带分别位于 5 49和 5 90 nm处 .邻位取代化合物的荧光量子产率为 0 .0 5 8,比间位 ( 0 .0 2 41 )、对位 ( 0 .0 2 3 5 )取代化合物的要高得多 .邻位取代化合物的荧光寿命( 3 .1 1 ns)比间位 ( 1 .1 2 ns)和对位 ( 1 .1 1 ns)取代化合物的长 .邻位化合物的这些特性可能归因于取代基之间的空间效应 ;而在间位和对位化合物中 ,重原子效应和吸电子的诱导效应可能起主导作用 .

On the basis of the spectroscopies such as UV absorption spectroscopy, fluorescence spectroscopy and time-resolved fluorescence spectroscopy, the photophysical properties of o-Cl, m-Cl and p-Cl substituted zinc(Ⅱ) tetraphenylporphyrin-tyrosine have been determined. It was found that the position of the chlorine atom has a great effect on the photophysical behavior of zinc(Ⅱ) tetraphenylporphyrin-tyrosine. Comparing to the m-Cl and p-Cl substituted compounds, abnormally high fluorescence quantum yield and longer fluorescence lifetime were observed in the o-Cl substituted compound and those may be ascribed to the steric effect.