体系酸度对多胺修饰β-环糊精与RhB包结配位作用的影响

The effect of acidity on Inclusion Complexation of Polyamine Modified β-cyclodextrins with RhB

在 p H值为 7.2和 2 .0的两种缓冲溶液中 ,分别用荧光光谱滴定技术测定了母体环糊精 ( 1 )、多胺修饰环糊精 ( 2、3、4)及其相应的铜配合物 ( 5、6、7)在 2 5℃时与 Rh B形成超分子配合物的稳定常数。结果表明 ,在 p H=2 .0时修饰环糊精 ( 2 -7)对 Rh B的识别能力时明显地低于 p H=7.2时的识别能力。从静电相互作用、疏水作用、氢键等方面讨论了主体化合物对 Rh B的分子识别机理。

The spectrofluorometric titrations have been performed to give the stability constants for the supramolecular systems formed by β-cyclodextrin (1) , mono [6-(ethylenediamine)-6- dexoy]-β-cyclodextrin(2), mono [6 - (diethylenetriamino) - 6 - dexoy] - β-cyclodextrin(3), mono [6 - (triethylenetetraamino) - 6 - dexoy] -β - cyclodextrin (4) and their copper (II) complexes (5?6?7) with RhB in phosphate buffer solution (pH 7.2, 0.1 mol·dm -3 ) and hydrochloric-acid potassium chloride buffer solution (pH 2.0, 0.1mol·dm -3 ) at 25℃. The results obtained indicated that the modified cyclodextrins(2-7) showed much lower affinitieds toward RhB in pH=2.0 than in pH=7.2. The molecular recognition mechanism is discussed from several factors of electrostatic interaction, hydrophobicity, hydrogen-bonding ability between host cyclodextrins and guest RhB molecular.