铜(Ⅱ)配合物与DNA作用的光谱法研究

采用紫外光谱和荧光光谱研究了配离子[Cu(A)₂]2＋(其中A=邻菲络啉(phen)，联吡啶(bpy)，乙二胺(en))与小牛胸腺DNA的相互作用。实验发现配合物的存在使DNA碱变性的pH增大，变性后增色效应减小。EB-DNA体系的荧光强度随[Cu(phen)₂]2＋的加入迅速减弱。在DNA存在下，配离子被猝灭剂[Fe(CN)₆]4-的发光猝灭程度减小。进一步研究了配体分子平面的大小对配合物与DNA作用的影响。结果表明，铜配合物与DNA之间发生了插入作用，且该作用随配体芳环平面的减小而减弱, 即[Cu(phen)₂]2＋＞[Cu(bpy)₂]2＋＞[Cu(en)₂]2＋。

Studies on the Interaction of Metalic Complex and DNA by the Spectral Methods

The interaction of 2 (A=phen,bpy,en) complex ion and ct DNA was investigated by using absorption spectra and fluorescence spectra. Based on the measurement of A 260 in the different pH mediums, the alkaline denaturation curves of DNA in the absence and in the presence of [Cu(phen) 2] 2 complex ion were obtained. The result showed that the alkaline denaturation for [Cu(phen) 2] 2 complex ion occured at a higher pH than that for DNA alone. The absorption of EB DNA system in the presence of [Cu(phen) 2] 2 showed that [Cu(phen) 2] 2 could partly sustain the place of EB. The result of fluorescence spectra suggested that the [Cu(phen) 2] 2 complex ion could make the fluorescence intensity of EB DNA system to decreased sharply. The effect of 4- on the emission of [Cu(phen) 2] 2 and [Cu(phen) 2] 2 DNA system was studied. All the experimental results indicated that the intercalative binding mode was the major mode for the interaction of [Cu(phen) 2] 2 complex ion and DNA, and the size of ligands can effect the binding of complexes to DNA.