2-(2-氨基苯基)苯并咪唑铂(Ⅱ)配合物的合成及其与BSA作用的光谱研究

Synthesis of 2-(2-Aminophenyl)Benzimidazole Platinum Complex and Spectral Study of its Interaction with BSA

以2-(2-氨基苯基)苯并咪唑(L 2)和K 2PtCl 4为原料反应合成铂配合物[Pt(L 2)2Cl 2]·H 2O(L 2-Pt),并获得其晶体结构。在生理条件下(pH 7.40),利用紫外吸收光谱、荧光光谱研究L 2和L 2-Pt对牛血清白蛋白(BSA)相互作用的影响。结果表明,L 2和L 2-Pt通过静态猝灭方式引起BSA荧光发生猝灭,在298、304、310 K这3个温度下,L 2-Pt对BSA的猝灭率及猝灭常数均大于L 2。焓变(ΔH)、熵变(ΔS)和吉布斯自由能变化(ΔG)表明,L 2与BSA间的作用力主要是疏水力(ΔH>0、ΔS>0),结合是自发进行的(ΔG<0);而L 2-Pt与BSA间的作用力主要是氢键和范德华力(ΔH<0、ΔS<0),结合也是自发进行的(ΔG<0)。紫外-可见吸收光谱和同步荧光光谱表明L 2-Pt并未使BSA的微结构发生改变。

The platinum complex[Pt(L 2)2Cl 2]·H 2O(L 2-Pt)was synthesized from 2-(2-aminophenyl)benzimidazole(L 2)and K 2PtCl 4 as raw materials.The corresponding crystal structure was obtained.The effect of L 2 and L 2-Pt to bovine serum albumin(BSA)was studied by UV absorption,fluorescence spectroscopy under physiological conditions(pH 7.4).The results revealed that L 2 and L 2-Pt caused the fluorescence quenching of BSA through a static quenching procedure,and the quenching rate and quenching constants of L 2-Pt on BSA are higher than those of L 2 at 298,304 and 310 K,respectively.The calculating of enthalpy change(ΔH)and the entropy change(ΔS)and gibbs free energy(ΔG)implied that the main interaction force of L 2 with BSA was hydrophobic force(ΔH>0,ΔS>0),and the binding process was spontaneous(ΔG<0).While the main interaction force of L 2-Pt with BSA was hydrogen bonds and van der Waals forces(ΔH<0,ΔS<0),and the binding process also was spontaneous(ΔG<0).The UV-Vis spectroscopy and synchronous fluorescence indicated that L 2-Pt did not alter the microstructure of BSA.