一种席夫碱铋配合物的合成及其与牛血清白蛋白的相互作用

Synthesis of a Bismuth Schiff Base Complex and its Interaction with Bovine Serum Albumin

摘要:

在非水体系中，以邻香草醛缩甘氨酸席夫碱与8-羟基喹啉、无水氯化铋合成一种三元配合物，通过元素分析、热分析、光谱分析等表征手段，确定其化学组成为[Bi(C10H10NO4)(C9H6NO)2]。席夫碱以酚羟基中的氧和C=N双键中的氮与铋(III)成键，8-羟基喹啉以氧、氮与铋(III)双齿配位，形成五元螯环。采用荧光法研究配合物与牛血清白蛋白（BSA）在不同温度下的相互作用，可知发生静态荧光猝灭，两者以摩尔比1：1结合形成复合物，结合常数为6.21×104 L/mol，ΔH和ΔS皆大于0，说明结合力主要为疏水作用；同步荧光扫描发现色氨酸残基的发射波长红移，表明复合物的形成导致BSA的构象发生了变化。

Abstract:

In the non-aqueous solvent system, a ternary complex was synthesized with o-vanillin-glycine Schiff base, 8-hydroxyquinoline and anhydrous bismuth chloride, which was confirmed to be [Bi(C10H10NO4)(C9H6NO)2], by elemental analysis, thermal analysis, spectral analysis, etc. Phenolic hydroxyl oxygen and the nitrogen of carbon-nitrogen double bond in the Schiff base were bonded to Bi(III) ion, and the oxygen atom and heterocyclic nitrogen atom of 8-hydroxyquinoline were bidentate-coordinated with Bi(III) ion, forming a five-member chelate ring. In particular, the interaction between the complex and bovine serum albumin (BSA) was investigated by fluorescence spectroscopy at different temperatures. It was proved that the fluorescence quenching of BSA by Schiff base-complex was a result of the formation of a complex with a stoichiometric ratio of 1:1. The quenching constant was calculated to be 6.21×104 L/mol. And the positive ΔH and ΔS values indicated that hydrophobic force might play a major role during the binding process. Finally, synchronous fluorescence spectroscopy was applied to examine the effect between complex and BSA. The tryptophan residue was found to decrease with a red shift of emission wavelength, which demonstrated that the complex changed the conformation of BSA.