发光型主体分子胍基芘识别二羧酸根阴离子

Selective Recognition of Dicarboxylates with a Pyrene-functionalized Quanidinium Receptor

在质子性溶剂甲醇中 ,发光型主体分子胍基芘通过氢键与二羧酸根阴离子结合 ,自组装形成 2∶1的主客体超分子复合物。本文采用前表面反射荧光检测 ,通过跟踪主体分子结合客体前后芘的激基二聚体与单体荧光强度比值的变化 ,研究了胍基芘对不同酸根数目、不同取代位置的苯取代羧酸盐、磺酸盐、长链二羧酸盐以及双羧基氨基酸的识别能力和识别选择性。结果表明 ,胍基芘对二羧酸根阴离子的识别能力与客体分子中两个羧基间的距离、分子的平面构型以及取代基的种类密切相关。 1,2 ,4,5 苯四甲酸根的识别效果远远好于其他二羧酸根阴离子。

The luminescent receptor pyrene functionalized quanidinium binds to dicarboxylates via hydrogen bonding in methanol solution containing 2% water.Ratiometric detection of the pyrene excimer to monomer fluorescence intensity revealed that the host molecule binds to pyromellitate more strongly than the other phenyl dicarboxylates and linear carbon chain dicarboxylates.Existence of the two pairs of ortho carboxylic groups in the pyromellitate enables the formation of complementary hydrogen bonding between the quanidinium group and the carboxylate.Dicarboxylates in the adjacent position like ortho phthalate and oxalate are the next strong binding guest anions.Amino acids with two carboxylic groups as well as disulfonate hardly bind to the quanidinium group of the host molecule.Our results show that the recognition is determined by the distance of the two carboxylic groups,the configuration and the substitution group.