Interaction of Cucurbit[n]urils and Quinoline or Its Derivates
DU Ying1, 2, XUE Sai-feng1*,MU Lan1, ZHU Qian-jiang1,TAO Zhu1,ZHANG Jian-xin3
1.Institute of Applied Chemistry, Guizhou University, Guiyang 550025, China 2.Department of Chemistry, Normal University of Guizhou, Guiyang 550001, China 3.The Key Laboratory of Chemistry for Natural Products of Guizhou Province, Guiyang 550002, China
Abstract:The structures and fluorescence characteristics of cucurbit[n=6-8]urils with quinoline, isoquinoline and 7-methyl quinoline have been investigated by fluorescence spectrophotometry.Compared to NMR techniques, the fluorometric analysis method revealed that there are not only obvious interactions of quinoline or its derivates and cucurbit[7]uril, but also interactions of quinoline or its derivates and cucurbit[6]uril or cucurbit[8]uril which can not be observed by using 1H NMR technique.The experimental results also revealed that quinoline, isoquinoline and 7-methyl quinoline were included by cucurbit[6-8]uril with different ratios.There could be three kinds of interactions of cucurbit[n]urils and the guests: a) cavity interaction, including hydrophobic forces and Van der Waals contact forces between macrocycles and cages; b) portals ion-dipole interaction, or electrostatic interaction of the positive charge of the guests and the carbonyl groups at the portals of cucurbit[n]uril; c)size interaction which requires the size of the guest matching a cucurbit[n]uril.
Key words:Cucurbit[n]urils;Quinoline and its derivates;Fluorescence spectrophotometry;1H NMR technique;Inclusion complexes