γ-环糊精与溴甲酚绿的包合作用

Complexation of γ-Cyclodextrin with Bromocresol Green

采用紫外-可见分光光度法和等摩尔连续变化法研究了γ-环糊精与溴甲酚绿的包合作用,确定了包合物形成的化学计量比为1∶2;采用热力学方法分析了温度与包合常数之间的关系,计算了包合过程的焓变、熵变及自由能变化分别为-39.988 kJ/mol,86.400 J/(K.mol)和-14.245 kJ/mol,这表明疏水作用力为主要驱动力;采用核磁共振、分子模拟和红外光谱法对包合物进行了研究,确定了包合物的形成,分析认为这可能是■基团进入γ-环糊精腔内导致增色效应.

UV-Vis and continuous variation plot method were used to study the complexation of γ-cyclodextrin with bromocresol green, and the stoichiometric ratio of the complexation was to be 1 ： 2. Thermodynamic analysis results show an inverse relationship between temperature and complexation constant, and the change of enthalpy, entropy and free energy of the complexation were -39. 988 kJ/mol, 86.400 J/（ K·mol） and - 14. 245 kJ/mol, respectively, which indicating that hydrophobic effect was the main force to form the complexes. γ-Cyclodextrin and bromocresol green complexes were examined by nuclear magnetic resonance, infrared spectrum and molecular modeling analysis, and was may be the group included in γ-cyclodextrin.