山奈酚-铜配合物的合成、表征及其抗氧化活性的研究

Synthesis,characterization and antioxidant activity of kaempferol-copper(Ⅱ) complex

以山奈酚和二水合氯化铜为原料,合成山奈酚-铜金属配合物,通过紫外光谱、红外光谱、核磁共振氢谱及差热-热重分析对其结构进行表征,并采用DPPH法测定了配合物清除自由基的能力。结果表明:相比山奈酚,配合物的紫外光谱和红外光谱的吸收峰均发生明显红移;核磁共振氢谱中3-OH信号消失,其他质子信号均向高场移动;差热-热重分析显示山奈酚和Cu^(2+)的配位比为1,且配合物中含三分子的配位水;在6种设定的实验浓度内(1.0~3.5 mol/L),山奈酚和配合物清除DPPH·半抑制浓度(IC_(50))分别为1.63×10^(-4)、1.51×10^(-4)mol/L。Cu^(2+)是通过与山奈酚3位羟基和4位羰基的氧原子结合生成配合物,山奈酚与铜形成配合物后,对DPPH自由基的清除率有提高。

Kaempferol-copper （II）complex （kaempferol-Cu）was synthesized with kaempferol and CuCl2·2H2O, and its chemical properties were characterized by UV spectroscopy, infrared speetroseopy,1H- NMR and differential thermal analysis. The free radical activity of the complex was evaluated by DPPH method.The result showed that the UV-visible, Infra -red absorption spectra of the complex both produced a significant bathochromic shift.The 1H NMR data shows the 3-OH groups was not presented in the complex, and the proton signals of the complex shifted to lower frequencies relative to that of the free kaempferol.The differential thermal-thermal analysis confirming that the stoichiometric ratio for the complexation of Cu （II） and kaempferol was 1： 1, and the complex contains three coordinated water molecules. In the range of experimental concentration（1.0-3.5 mol/L） , the IC50 of DPPH free radical of the kaempferol and complex was 1.63 × 10-4, 1.51 × 10-4 mol/L respectively. The synthesized complex was coordinated with a Cu （II） ion via the 3- OH and 4-oxo groups, kaempferol-Cu exhibited more potent antioxidant effect than kaempferol.