Supramolecular Self-Assembly Based on Symmetric Tetramethyl-Substituted Cucurbit[6]uril and Small Aromatic Amines

Abstract

In this paper, the interactions formed between symmetric tetramethylsubstituted cucurbit[6]uril (TMeQ[6]) and 4-cyanoaniline (CYA), 4,4'methylenedianiline (MET), and 4-benzylaniline (BEN), were investigated using 1 H NMR spectroscopy and X-ray single crystal diffraction analysis. X-Ray single crystal diffraction showed that CYA was encapsulated in the cavity of TMeQ[6] and formed 1:1 host-guest complex 1. Both MET and BEN were located at the TMeQ [6] portal and coordinated to form complex 2 and complex 3, respectively, forming weak interactions with TMeQ[6], such as hydrogen bonding, C-H•••π interactions, and ion-dipole interactions. Complexes 1~3 self-assemble to construct supramolecular nanoscale structures under the induction of [ZnCl4] 2ions. The 1 H NMR spectroscopic analysis supported the crystallographic results in which an clathration or portal interaction occured between host and guest molecules.