稀土N,N′-双(2-吡啶甲酰胺)-1,2-乙烷配合物合成及与DNA的作用  

Synthesis and Study on the Interaction of Rare Earth Complexes of N',N-Bis(2-Pyridinecarboxamide)-1,2-Ethane with DNA

作　　者：陆晓红[1] 林秋月[1] 胡瑞定[1] 刘卫东[1] 冯洁[1] 

机构地区：[1]浙江师范大学化学与生命科学学院化学系,浙江金华321004

出　　处：《光谱学与光谱分析》2007年第6期1176-1180,共5页Spectroscopy and Spectral Analysis

基　　金：浙江省自然科学基金项目(Y404031);浙江师范大学无机化学重点学科项目资助

摘　　要：合成了四种N,N′-双(2-吡啶甲酰胺)-1,2-乙烷(H2L)稀土配合物。经过对元素分析,红外光谱,紫外光谱,热重分析和摩尔电导值的分析,确定配合物的组成为:[Ln(H2L)(NO3)2](NO3)·3H2O(Ln=Sm,Eu,Gd,Tb)。光谱测试结果表明:配体H2L中酰胺羰基氧和吡啶氮分别与稀土离子配位,硝酸根为双齿配体,Ln(Ⅲ)与H2L形成了1:1的螯合物。另外,通过紫外光谱、荧光光谱和表面增强拉曼光谱方法对Sm配合物与DNA之间的作用进行了初步的研究。实验结果显示随着DNA的加入[Sm(H2L)(NO3)2](NO3)·3H2O配合物在265nm处的紫外吸收峰逐渐减小,并产生红移现象,得到配合物与DNA的结合常数为1·24×105。Sm配合物使EB-DNA体系发生荧光猝灭,由于配合物和EB争夺与DNA的结合位点,从而使体系中游离的EB增多。表面增强拉曼光谱峰的变化亦显示随着DNA的加入配合物的谱峰强度减弱,同时1282cm-1处的谱峰消失,说明配体的吡啶环在一定程度上插入了DNA的双螺旋平面,导致吡啶环的电子云密度发生改变。以上结果表明配合物和DNA发生了显著的作用。Four rare earth complexes of N＇, N-bis（2-pyridinecarboxamide）-1, 2-ethane were synthesized and characterized by elemental analysis, conductivity measurement, thermal studies, IR and electronic spectra. The composition of the four complexes is [Ln（H2L） （NO3）2]（NO3）· 3H2O （Ln=Sm, Eu, Gd, Tb）. Results of spectral measurements indicate that the oxygen of carbonyl and the nitrogen of pyridyl coordinate with Ln（ Ⅲ ） respectively, and the NO3^- shows bidentate coordination. So the four complexes are 1 ： 1 chelated complexes. The interaction between [Sm（H2L）（NO3 ）2] （NO3） · 3H2O and DNA was studied by employing UV-Visible （UV-Vis） spectra, fluorescence spectra and SERS spectra. Experimental results show that with the incremental addition of DNA, the bands at 265 nm show hypochromism accompanied by a small red shift and the binding constant Ks obtained is 1.24 × 10^5. Meanwhile fluorescence spectra show that the addition of [Sm（ H2 L） （NO3） 2 ] （ NO3 ） · 3 H2 O to DNA pretreated with EB causes an appreciable reduction in fluorescence intensity, indicating that the complex competes with ethidium bromide in binding to DNA, and free ethidium bromide increases. The addition of DNA causes the SERS signals of the complex to weaken and the band at 1 282 cm^-1 to disappear, which suggests that the planar pyridine molecule of the ligand may partly be inserted into the double-stranded helix plane in DNA, making π electronic density of aromatic rings in complex change. The above phenomena indicate that [-Sm（H2 L） （NO3） 2 ]（NO3） · 3 H2 O interacts intensively with DNA.

关 键 词：稀土 吡啶甲酰胺 配合物 光谱法 DNA作用 

分 类 号：O614.3[理学—无机化学] O626.3[理学—化学]