Main-Chain Supramolecular Polymers Based on Orthogonal Benzo-21-Crown-7/Secondary Ammonium Salt and Terpyridine/Metal Ion Recognition Motifs

摘要

Orthogonal self-assembly of multiple components represents an effi cient strategy to afford hierarchical and multifunctional assemblies. Here, we demonstrate the orthogonal recognition behaviors between benzo-21-crown-7/secondary ammonium salt and terpyridine/metal ions (Fe~(2+) or Zn~(2+)) recognition motifs. Main-chain supramolecular polymers are subsequently achieved via "one-pot" mixing of the three monomers together (heteroditopic monomer 1, homoditopic secondary ammonium salt monomer 2, and Fe(BF_4)_2 ?6H_2 O or Zn(OTf)_2), which are confi rmed by ~1H NMR, UV-Vis, DOSY, and viscosity measurements. Moreover, different metal ions (Fe~(2+) or Zn~(2+)) exert considerable effects on the size of the resulting supramolecular polymers. Integration of two different types of non-covalent interactions renders dynamic and responsive properties for the resulting supramolecular polymers, as triggered by a variety of external stimuli such as temperature, potassium cation, as well as stronger chelating ligands. Therefore, the current work is a prerequisite for the future application of such orthogonal assemblies as intelligent supramolecular materials.