Fluorescent Metallacage-Core Supramolecular Polymer Gel Formed by Orthogonal Metal Coordination and Host-Guest Interactions

J Am Chem Soc. 2018 Jun 20;140(24):7674-7680. doi: 10.1021/jacs.8b03781. Epub 2018 Jun 12.

Abstract

Herein, we report the preparation of a multifunctional metallacage-core supramolecular gel by orthogonal metal coordination and host-guest interactions. A tetragonal prismatic cage with four appended 21-crown-7 (21C7) moieties in its pillar parts was first prepared via the metal-coordination-driven self-assembly of cis-Pt(PEt3)2(OTf)2, tetraphenylethene (TPE)-based sodium benzoate ligands and linear dipyridyl ligands. Further addition of a bisammonium linker to the cage delivered a supramolecular polymer network via the host-guest interactions between the 21C7 moieties and ammonium salts, which formed a supramolecular gel at relatively higher concentrations. Due to the incorporation of a TPE derivative as the fluorophore, the gel shows emission properties. Multiple stimuli responsiveness and good self-healing properties were also observed because of the dynamic metal coordination and host-guest interactions used to stabilize the whole network structure. Moreover, the storage and loss moduli of the gel are 10-fold those of the gel without the metallacage cores, indicating that the rigid metallacage plays a significant role in enhancing the stiffness of the gel. The studies described herein not only enrich the functionalization of fluorescent metallacages via elegant ligand design but also provide a way to prepare stimuli-responsive and self-healing supramolecular gels as robust and smart materials.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Benzylidene Compounds / chemical synthesis
  • Benzylidene Compounds / chemistry
  • Coordination Complexes / chemical synthesis
  • Coordination Complexes / chemistry*
  • Crown Ethers / chemical synthesis
  • Crown Ethers / chemistry
  • Fluorescence
  • Gels / chemical synthesis
  • Gels / chemistry*
  • Macromolecular Substances / chemical synthesis
  • Macromolecular Substances / chemistry*
  • Organoplatinum Compounds / chemical synthesis
  • Organoplatinum Compounds / chemistry*
  • Polymers / chemical synthesis
  • Polymers / chemistry*
  • Rheology

Substances

  • Benzylidene Compounds
  • Coordination Complexes
  • Crown Ethers
  • Gels
  • Macromolecular Substances
  • Organoplatinum Compounds
  • Polymers