光谱法研究羟基葫芦[6]脲与甲基橙的分子识别作用

采用紫外和荧光光谱法研究羟基葫芦6]脲(HOCB6)与甲基橙(MO)之间的包结作用，考察了溶液的pH值、常见有机溶剂和表面活性剂等对该包结物的形成及荧光强度的影响。实验结果表明，随着主体分子的加入，MO荧光增强且蓝移，说明客体被纳入主体分子的疏水性穴腔，形成内包结物。主客体分子之间主要通过疏水作用形成1∶1型的HOCB6-MO包结物，其包结常数为1.41×102 L·mol-1。同时采用葫芦6]脲(CB6)、对-二甲氨甲基杯8]芳烃和β-环糊精与MO的作用进行比较。研究发现，MO也能与葫芦6]脲形成1∶1型的内包结物，但包结常数较小(34.65 L·mol-1);与β-环糊精形成1∶2型的内包结物，其包结常数为6.14×106 L2·mol-2;与对-二甲氨甲基杯8]芳烃形成1∶1型的外包结物，导致荧光强烈猝灭，包结常数为1.35×104 L·mol-1。

Study on the Molecular Recognition of Perhydroxycucurbit[6]uril with Methyl Orange by Spectroscopic Methods

The inclusion interaction of perhydroxycucurbit6] uril (HOCB6) with methyl orange (MO) was studied by UV spectroscopic and fluorimetric methods. Several effect factors, such as pH values, common organic solvents and surfactants on the fluorescence intensity and the stability of the complex were investigated. The results indicate that the fluorescence intensity of MO was enhanced with a blue shift as host molecules were added, showing that MO was accommodated into the hydrophobic cavities of HOCB6 and an endo-inclusion complex was formed. The hydrophobic interaction between HOCB6 and MO mainly contributed to the formation of 1 : 1 type HOCB6-MO. Its complex constant was determined to be 1.41 x 10(2) L x mol(-1). The comparative study of HOCB6 with other supramolecules, such as cucurbit6] uril (CB6), p-(N,N-dimethyl-aminomethyl) calix 8]arene and beta-cyclodextrin, was also carried out by using MO as a guest probe. The spectra changes showed that cucurbit6] uril (CB6) can also form 1 : 1 type endo-inclusion complex with MO, which is similar to HOCB6, but its complex constant (34.65 L x mol(-1)) is small. The spectra changes also showed that the endo-inclusion complex with 2 : 1 type was formed between beta-cyclodextrin and MO, While the exo-inclusion complex was formed between p-(N,N-dimethyl-aminomethyl) calix8] are-ne and MO, leading to fluorescence quenching, and their complex constants were determined to be 6.14 x 10(6) L2 mol(-2) and 1.35 x 10(4) L x mol(-1), respectively.