超分子主体化合物及其对核黄素的包合作用

【作者】 顾静；

【导师】 刁国旺；

【作者基本信息】 扬州大学 ， 物理化学， 2006， 硕士

【摘要】 一.对叔丁基杯[8]芳烃在二氯甲烷中的电化学性质通过循环伏安法研究了对叔丁基杯[8]芳烃在二氯甲烷中的电化学特性。以玻碳电极为工作电极,在–0.3¹.6V （vs. Ag/0.1M AgNO₃）的电位范围内存在一个不可逆的电化学氧化峰,在有机溶剂中电化学反应过程受溶液电阻影响较大,主要表现为支持电解质（TBAP）浓度对电化学反应的影响,当支持电解质浓度小于0.5 mol·L^-1时,峰电位和峰电流均随着支持电解质浓度的变化而不断改变。在250C,当支持电解质浓度为0.5 mol·L^-1,扫描速率为0.05 Vs^-1时,峰电位在1.43 V （vs.Ag/Ag⁺）处,反应过程受扩散控制。并计算得电化学反应的电子转移数为4,比杯[4,6]芳烃磺酸盐在酸性水溶液中的电子转移数都大。对叔丁基杯[8]芳烃的扩散系数为2.8×10-5 cm2·s^-1,扩散活化能为12.3 kJ·mol^-1。二.羟丙基β-环糊精与核黄素的相互作用通过光谱法、相溶解度法和热力学方法研究了羟丙基β-环糊精与核黄素的相互作用。随羟丙基β-环糊精的浓度增大,核黄素的荧光强度增强,证明两者非共价包结作用的存在,并通过Benesi-Hildebrand方法计算该条件下的形成常数为351.6 L·mol^-1。在相溶解度法研究中利用Higuchi-Connors方法,得到了与光谱法研究中完全一致的形成常数。另外,在酸性([HCl]=1×10-4mol·L^-1)情况下随着羟丙基β-环糊精浓度由0逐渐增加到0.025 mol·L^-1时,核黄素的溶解度由72.45 mg·L^-1增加到230.26 mg·L^-1,而在完全相同的条件下β-环糊精的饱和溶液中,核黄素的溶解度为152.63 mg·L^-1。计算了弱酸性溶液中羟丙基β-环糊精与核黄素在本实验条件下相互作用的热力学常数如:吉布斯自由能变(-14.36 kJ·mol^-1)、熵变(-332.68 J·mol^-1·K^-1)、焓变(-113.50 kJ·mol^-1)等。更多还原

【Abstract】 1. Electrochemical behavior of p-tert-butyl calix[8]arene in CH2Cl2The electrochemical behavior of p-tert-butyl calix[8]arene has been investigated by cyclic voltammetry. The result shows that there is an irreversible electrochemical oxidative wave when the potential ranges from–0.3 to 1.6 V vs. Ag/0.1M AgNO₃ in acetonitrile （Ag/Ag⁺）. In an organic system, a distorted voltammogram is often observed because of high solution resistance which can be confirmed by changing the concentration of the supporting electrolyte（TBAP）. Both current and peak potential affected by the concentration of TBAP until cTBAP≥0.5 M. At 25oC, cTBAP=0.5 M, the peak potential is ca. 1.43V （vs. Ag/Ag⁺） at scan rate of 0.05 Vs^-1. The number of the electrons transferred in the electrochemical reaction is 4, which is more than that of p-sulfonated calix[4,6]arene in acidic aqueous solution. The diffusion coefficient of p-tert-butyl calix[8]arene is 2.8×10-5 cm2·s^-1. The diffusion activation energy is 12.3 kJ·mol^-1.2. The effect of cyclodextrin on drug of riboflavinCyclodextrins are often used in order to increase the aqueous solubility of drug substances by complexation. In order to investigate the complexation reaction of riboflavin （RF） and hydroxypropyl-cyclodextrin （HP-β-CD）, the spectroscopy, phase solubility and thermodynamics methods were used as direct methods. However, when increasing concentrations of HP-β-CD are added, an increase in the fluorescence signal is observed, attesting the formation of a non-covalent inclusion complex between riboflavin and HP-β-CD. In this work, the corresponding formation constant (351.6 L·mol^-1) has been determined from fluorescence data by Benesi–Hildebrand’s method. In the phase solubility studies, the formation constant was also obtained according to Higuchi and Connors’s method. Additionally, a great increase in solubility from 72.45 mg·L^-1 to 230.26 mg·L^-1 was observed at 0.025 mol·L^-1 HP-β-CD and [HCl]= 1×10-4 mol·L^-1 while 152.63 mg·L^-1 was observed at saturatedβ-CD. The thermodynamic更多还原