尾式锌卟啉轴向配位反应的光谱性质

The Spectroscopic Properties of Axial Coordination Reaction of Zn Porphyrins

采用紫外-可见光谱和荧光光谱滴定方法考察了5-p-(4-溴乙氧基)苯基-10,15,20-三苯基锌卟啉和5-p-(4-烟酸乙氧基)苯基-10,15,20-三苯基锌卟啉与咪唑类客体之间的配位反应性质。热力学实验研究结果表明,2种锌卟啉与咪唑类客体之间的轴配反应是按摩尔比1∶1进行的,轴配反应的平衡常数均按K(2-MeIm)>K(N-MeIm)>K(Im)的顺序依次减弱,其中5-p-(4-烟酸乙氧基)苯基-10,15,20-三苯基锌卟啉与2-甲基咪唑间的轴配反应有更大的平衡常数,为5.46×105L/mol。荧光光谱滴定实验显示,随客体浓度的增加,2种主体与咪唑类客体形成的轴配体系均具有荧光猝灭效应。

The axial coordination reaction between two kinds of Zn porphyrins [p-BrC2H40-ZnTPP and p- （niacin）C2H40-ZnTPP1 and imidazole derivatives was studied by using of UV-Vis spectroscopy and fluorescence spectroscopy titrations. The results showed that the axial coordination reaction was carried out in a molar ratio of 1：1 between Zn porphyrins and imidazole derivatives. The association constants in the system of axial coordination reaction decrease in the order ofK（2-MeIm） 〉 K（N-Melm） 〉 K（Im）, in which the better association constant was 5.46 × 105 L/mol between p-（niacin） C2H4O-ZnTPP and 2-MeIm. And then, the fluorescence quenching was exhibited with the increasing concentration of imidazole derivatives in the system of axial coordination reaction.