The Synthesis Of A New Type Of Macrocyclic Compound Benzo[6]urils And The Study Of Its Supramolecular Properties

A new class of macrocyclic compounds Benzo[6]urils?Benzo[6]uril 1 and Benzo[6]uril 2?with a hydroxymethyl or methyl group was synthesized in high yield under mild conditions.The fluorescence response of Benzo[6]urils can be applied for recognition toorganic small molecules such as bipyridines,coumarins.Fluorescence titration confirmed that the formation of interaction complexes ofin a ratio of 1:1,and the association constants were obtained by curve-fitting of fluorescence decrease.In the cases of interactions of Benzo[6]urils with bipyridine guests,the constantsin the rangefrom 10³ to 10⁶ L·mol^-1 demonstrated that the stability of the supramolecular complex depends on the structure of the guest and the substituents present on the host,while in the cases of interactions of Benzo[6]urils with coumarin guests,the constants were calculated to be 1.9×10⁴⁶.4×10⁴ L·mol^-1,which is due to the formation of hydrogen bonds between the guests and the carbonyl group of the host compound.There are small changes ofthe proton resonance singals on aromatic ring of the host compound in the¹H NMR titration in the host-guest interactions.And then,based on the above analysis of experimental results,the molecular simulation of the interaction complexes of Benzo[6]urils and guests wereperformed with DFT-Dmethod.To explore the potential application of Benzo[6]urils as a sort of materials,the graphene oxide?GO?modified by benzo[6]urils was prepared by a wet chemical method and characterized by atom force microscope and IR,and then were applied for the investigation of its host-guest intereaction with 4-methyl umbelliferone and7-hydroxycoumarin.The results indicated that the modified GO with BU[6]s greatly enhances the response to the host-guest interaction.