【摘要】 采用元素分析、~1H核磁共振谱(~1H NMR)和电喷雾电离质谱研究了两个大环主体分子β-环糊精(β-CD)和18-冠-6(18C6),结果显示,二者通过简单地混合形成了计量比为1:1的超分子包合物18C6-β-CD.基于二维核磁共振谱(ROESY)的分析,提出了分子间相互作用的可能位点:18C6更倾向于驻留在β-CD的小口端.用热重分析和气相色谱飞行时间质谱比较了包合作用前后热降解过程包括降解度和降解产物的差异性,研究表明,18C6的存在促使β-CD提前分解,同时,由于分子间相互作用,导致二者分解产物中大碎片的相对含量大幅减小.这些结果显示,一个柔性大环分子18C6和一个刚性大环分子β-CD之间通过分子组装可以形成超分子包合物.更多还原

【Abstract】 The formation of a 1:1 supramolecular complex betweenβ-cyclodextrin(β-CD) and 18- crown-6(18C6) by simply mixing them was confirmed by elemental analysis,~1H nuclear magnetic resonance(~1H NMR) and electrospray ionization mass spectrometry.The probable interaction sites between these species were determined by two-dimensional rotating frame nuclear Overhauser effect spectroscopy(ROESY),which showed that 18C6 tended to be located on the narrow end of the cavity ofβ-CD.Also,the degradation process including the degree of degradation and the degradation products of the complex was carefully compared with those ofβ-CD and 18C6 through thermogravimetric analysis and gas chromatography coupled to time-of-flight mass spectrometry.The experimental data indicated that the presence of 18C6 resulted in an earlier degradation ofβ-CD.Furthermore,the relative abundance of larger fragments from the degradation process of the two components was reduced drastically because of an intermolecular interaction.These results strongly indicate that a supramolecular complex can be constructed using the flexible macrocyclic molecule 18C6 as a guest and the rigid macrocyclic moleculeβ-CD as the host via molecular assembly between them.更多还原