【摘要】 298.15K下,以滴定式微量热法研究β-环糊精与三个同系列烷基三甲基溴化铵(CnBr,n=8,12,14)在水溶液中的包合作用.在实验条件下,β-环糊精未能与C8Br稳定包合,却与C12Br和C14Br形成化学计量比为1∶1的主-客体包合物.对应于n=12,14,所得包合物的实验稳定常数分别为:β1=1.09×103L.mol-1,β1=14.80×103L.mol-1.包合物的形成过程都是焓、熵协同驱动的过程.从主、客体的微观结构出发对实验结果进行了讨论.更多还原

【Abstract】 Interactions between β-cyclodextrin(β-CD)and alkyl trimethyl ammonium bromides(CnBr,n= 8,12,14)in aqueous solutions were investigated with titration microcalorimetry at 298.15 K.No stable complexation was observed between β-CD and C8Br,while host-guest inclusion complexes of 1.1 stoichiometry were formed between β-CD and either of the other two CnBr with the apparent experiential stability constants being β1=1.09×103 dm3·mol-1,β1 =14.80×103 dm3·mol-1,respectively for n=12,14.All the complexation processes were proved to be both enthalpy and entropy beneficial and the standard enthalpy effect(ΔHo)decreases with elongation of the hydrophobic chain.The results were discussed in the light of the microstructure of the host and guest molecules.更多还原