三(2苯-甲酰胺乙基)胺及其Eu^(3＋)配合物的合成、表征及与DNA作用研究

Synthesis,Characterization of Eu^(3+) Complex with Tris(2-Benzoyl Aminoethyl) Amine Base and Interactions with DNA

合成了新型三脚架结构配体三(2-苯甲酰胺乙基)胺及其稀土Eu3+配合物。通过元素分析、IR、1H-NMR、TG-DTA和摩尔电导对此化合物进行组成和结构推测,结果显示配合物[EuL(NO3)2].NO3是1∶1型配位,3个硝酸根中有两个处于配位内界与Eu3+配位,总配位数为8。通过紫外吸收光谱、荧光发射光谱、粘度法及其与溴化乙啶(EB)的竞争实验研究了配合物与ct-DNA的作用情况,结果显示,配合物与ct-DNA作用时,其紫外吸收产生明显增色效应,荧光强度增强;EB-DNA体系的荧光强度随配合物的加入迅速减弱;配合物的加入使ct-DNA的粘度增加;实验结果证明,配合物与ct-DNA以插入方式结合,其键合常数Kq=8.86×103L·mol-1。凝胶电泳实验表明配合物[EuL(NO3)2].NO3不能将pUC19 DNA选择性的断裂成线型和开环型DNA,并分析讨论了其原因。

The synthesis of a new tripod ligand and its Eu3＋ complex were reported.The complex was characterized by elemental analysis,IR,1HNMR,TG-DTA and molar conductance measurements.The results showed the complex [EuL（NO3）2]·NO3 was 1∶1 electrolyte,where the two of the three nitrate radicals were in di-dentate coordination with Eu3＋ ions;the coordination number was 8.DNA-binding properties of the complex were investigated using UV spectra,fluorescent spectra,viscometry,steady-state emission quenching and DNA competitive binding with ethidium bromide（EB）.The results showed that the intensity of absorption peaks and fluorescence peaks increased when the complex interacted with ct-DNA.The complex could make the fluorescence intensity of EB-DNA system decreased sharply.The relative specific viscosity of ct-DNA increased with the increasing concentration of complex,and the constants was Kq=8.86×103 L·mol-1.All the experimental results indicated that the binding-mode between complex and ct-DNA was intercalation.Photoactivated cleavage of pUC19 DNA by complex was studied.The agarose gel electrophoresis showed that the complex EuL（NO3）2·NO3 could not photo-cleave the supercoiled pUC19 DNA to nicked and linear DNA selectively and the reasons were discussed.