烟酸修饰尾式卟啉的合成及其与人血清白蛋白的相互作用

摘要

合成了烟酸分子修饰的自由卟啉o-(niacin)C2O-T(3p-OCH3)PP、p-(niacin)C2O-T(3p-OCH3)PP及锌配合物o-(niacin)C2O-T(3p-OCH3)PPZn、p-(niacin)C2O-T(3p-OCH3)PPZn.经元素分析、紫外-可见光谱、核磁共振氢谱(1H NMR)、红外(IR)光谱等对结构进行了表征,并通过量子化学方法计算了锌卟啉的最低能量构型.实验结果表明:o-(niacin)C2O-T(3p-OCH3)PPZn中侧链烟酸基团处于卟啉环上方,烟酸基团中N原子与卟啉环中Zn2+存在着Zn-N间的分子内配位作用,而p-(niacin)C2O-T(3p-OCH3)PPZn中侧链烟酸基团处于卟啉环较远的位置,一个锌卟啉的中心Zn2+与另一个锌卟啉烟酸中N原f之间存在着Zn-N间的分子间配位作用.同时,为模拟金属卟啉的生物功能,采用荧光光谱滴定法测定了金属锌卟啉与人血清白蛋白相互作用的光谱性质.荧光光谱实验结果显示:金属锌卟啉与人血清白蛋白(HSA)之间发生了较强的静态荧光猝灭作用,反应机理是以氢键或van der Waals力结合反应.按照Stern-Volmer方程、Lineweaver-Burk双倒数方程分析和处理实验数据,得到了反应的猝灭常数、结合常数和热力学参数等.%Free porphyrins, namely o-(niacin)C2O-T(3p-OCH3)PP and p-(niacin)C2O-T(3p-OCH3)PP, their complexes, o-(niacin)C2O-T(3p-OCH3)PPZn and p-(niacin)C2O-T(3p-OCH3)PPZn modified with nicotinic acid, were designed, synthesized, and characterized by elementary analysis, and UV-Vis, 1H nuclear magnetic responance (1H NMR), and infrared (IR) spectroscopies. The conformations of the Zn porphyrins were calculated using a quantum- chemical method. The experimental results showed the following. It was found that the nicotinic acid group was on the porphyrin plane in o-(niacin)C2O-T(3p-OCH3)PPZn and Zn -N intramolecular coordination interactions which existed between the N atom of the nicotinic acid group in the side-chain and the Zn2+ in the porphyrin plane. The nicotinic acid group was far from the porphyrin plane in p-(niacin)C2O-T(3p-OCH3)PPZn and Zn - N intermolecular coordination interactions which existed between the N atom of the nicotinic acid group in one Zn porphyrin and the Zn2+ in the other porphyrin plane. The fluorescence properties of the interactions between Zn porphyrins and human serum albumin (HSA) were studied using fluorescence spectroscopy. There is a large quenching interaction between the Zn porphyrins and human serum albumin. The mechanism of the combination reaction is hydrogen bonding or van der Waals interactions between the Zn porphyrins and human serum albumin. The fluorescence quenching data were analyzed using the Stem-Volmer equation and a double-reciprocal equation, and the quenching constant, binding constant, and thermodynamic parameters were obtained.