Supramolecular nanoassemblies of rim-differentiated pillar[5]arene-rod-coil macromolecules via host-guest interactions for the sensing of cis-trans isomers of 1,4-diol-2-butene

Abstract

Over the past few years, pillar[n]arene molecules have gained attention as novel functional materials due to their unique properties, including their pore size structure and exceptional host-guest capabilities. Among them, rim-differentiated pillar[5]arene is particularly favored for its unique asymmetric structure. In this study, we present a self-assembled macrocyclic host molecule (H1) based on a rim-differentiated pillar[5]arene unit and five rod-coil side chains containing a hepta (ethylene glycol) mono-methyl ether modified biphenyl and phenyl groups, which was self-assemble into 2D columnar nanostructures in the bulk state. It self-organizes into a double-layer vesicular aggregate when in a CHCl3 solution. The host-guest interactions between the nanoobjects and the guest molecule (G) composed of tetraphenylethene and hexanenitrile groups resulted in the construction of ordered nanostructures with good luminescent properties, such as lamellar nanostructure in the bulk state and a single-layer nanosheet in CHCl3 solution. This demonstrated that the morphology of the H1 can be manipulated by forming host-guest complexes, and by adjusting the intermolecular interactions between the molecules. Moreover, in the presence of cis-trans isomers of 1,4-diol 2-butene, we successfully separated and visually detected the trans isomers through competitive host guest interactions. This result not only provides a general approach for separating the cis-trans isomers of 1,4-diol 2-butene through supramolecular chemistry, but also sets a precedent for future research in this field.