【摘要】 用光谱滴定技术分别测定了β-环糊精(1)、单-[6-(1-萘酰氨基)-乙基氨基-6-脱氧]-β-环糊精(2)、单-[6-(1-萘酰氨基)-二乙基二氨基-6-脱氧]-β-环糊精(3)在25℃时,pH为7.2、2.0和10.1的缓冲溶液中与几种染料分子形成超分子配合物的稳定常数Ks,并考察了pH=7.2时识别过程的热力学参数ΔH0和TΔS0。结果表明,pH为2.0和10.1时,静电、疏水和氢键作用协同贡献于超分子配合物的形成,如主体2与AR在pH=10.1时形成的Ks=7085;而pH=2.0时的Ks=1034。当pH=7.2时主-客体的尺寸/形状匹配、疏水作用和范德华力决定配合物的稳定性。主体2、3对AR、TNS和ANS的包结配位是放热过程,并给出较大的焓变(-ΔH0),对RhB主要表现为熵驱动过程。更多还原

【Abstract】 The spectral titrations have been performed to give the stability constants Ks for the supermolecular systems formed by βcyclodextrin(1),mono [6-(1-naphthyloxamino)ethylenediamino)-6-dexoy]β-cyclodextrin(2),mono [6-(1-naphthyloxamino)diethylenediamino)-6-dexoy]-β-cyclodextrin(3),with some dyes in aqueous buffers of pH 7.2,2.0 and 10.1 at 25℃.Moreover,the thermodynamic parameters(ΔH and TΔS) for the inclusion complexation were also calculated at pH 7.2.The results obtained indicated that electrostatic,hydrophobic and hydrogen bonding interactions cooperatively contributed to the formation of(supramolecular) complexes at pH 2.0 and pH 10.1 respectively.Typically,host 2 with acridine red(AR)(displayed) the binding ability(K_s=7085) at pH 10.1,but K_s=1034 at pH 2.0.On the other hand,the size/shape-matching between host and guest, hydrophobic and van der Waals interactions determined the(stability) of inclusion complex at pH 7.2.The inclusion reactions of 2,3 with AR,sodium-2-pmethyl(phenylamino-6-naphthalene) sulfonate(TNS) and ammonium-phenylaminonaphthalene sulfonate(ANS) were exothermic,giving the larger negative enthalpic gain(-ΔH),but the inclusion complexation with RhB was mainly entropy-driven contribution.更多还原