8-羟基喹啉-山梨酸稀土配合物与鲱鱼精DNA相互作用的光谱研究

合成了以山梨酸(SA)和8-羟基喹啉(Hq)为配体的Sm(Ⅲ)、Eu(Ⅲ)为中心的三元稀土配合物,研究了配合物与DNA之间的作用机制。采用红外光谱、紫外-可见吸收光谱、差热热重、元素分析和摩尔电导等方法,确定了配合物的化学组成,采用光谱法探讨了配合物与鲱鱼精DNA的作用机制。结果表明:配合物的化学组成为Sm(Hq)(SA)2和Eu(Hq)(SA)2,其最大吸收峰在加入DNA后发生减色和红移,中性红(NR)使配合物-DNA体系的吸收发生减色,伴有等色点出现。配合物的加入导致NR-DNA体系的吸收峰强度和位置发生变化。计算求得Eu(Hq)(SA)2和Sm(Hq)(SA)2分别与DNA的结合位点数为5,在20℃下,Sm(Hq)(SA)2、Eu(Hq)(SA)2与DNA的结合常数分别是2.04×104L/mol和1.09×104L/mol。2种稀土配合物都能不同程度地猝灭NR-DNA体系的荧光,表明2种稀土配合物对DNA都有较强的嵌插作用且能自发进行,结合能力为Sm(Hq)(SA)2Eu(Hq)(SA)2。

DNA Binding of Rare Earth Complexes Containing Mixed Ligands of Sorbic Acid and 8-Hydroxyquinoline by Spectroscopy

Two complexes of rare earth with sorbic acid (SA) and 8-hydroxyquinoline (Hq) were synthesized and the interaction with DNA were investigated.The rare earth complexes were characterized by elemental analysis,IR,UV-Vis,TG-DTA and molar conductance.The compositions of the complexes were confirmed to be Sm(Hq)(SA)2 and Eu(Hq)(SA)2.The interactions between complexes and herring sperm DNA were investigated by spectral methods.The absorption peaks of the complexes shift and are weakened with the interaction of DNA.Moreover,accompanied by a red shift,the absorption peak intensity of complex-DNA system is weakened with the adding of NR.The absorption peak intensity and position of NR-DNA system change with the adding of complex,indicating a new balance system among complex,NR and DNA.The combining ratios of Sm(Ⅲ) complex and Eu(Ⅲ) complex with DNA are all 5:1,the binding constants are 2.04×104 and 1.09×104 L/mol at 20 ℃,respectively.The complex can remarkably quench the emission intensity of NR-DNA system.All the above results indicate that the interaction mode of the complexes with DNA belong to intercalative,and the sequence of binding ability of the complexes to DNA is Sm(Hq)-(SA)2> Eu(Hq)(SA)2.