Higher-generation type III-B rotaxane dendrimers with controlling particle size in three-dimensional molecular switching

Nat Commun. 2018 Feb 5;9(1):497. doi: 10.1038/s41467-018-02902-z.

Abstract

Type III-B rotaxane dendrimers (T3B-RDs) are hyperbranched macromolecules with mechanical bonds on every branching unit. Here we demonstrate the design, synthesis, and characterization of first to third (G1-G3), and up to the fourth (G4) generation (MW > 22,000 Da) of pure organic T3B-RDs and dendrons through the copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction. By utilizing multiple molecular shuttling of the mechanical bonds within the sphere-like macromolecule, a collective three-dimensional contract-extend molecular motion is demonstrated by diffusion ordered spectroscopy (DOSY) and atomic force microscopy (AFM). The discrete T3B-RDs are further observed and characterized by AFM, dynamic light scattering (DLS), and mass spectrometry (MS). The binding of chlorambucil and pH-triggered switching of the T3B-RDs are also characterized by 1H-NMR spectroscopy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Copper / chemistry
  • Dendrimers / chemical synthesis*
  • Dendrimers / chemistry
  • Macromolecular Substances
  • Models, Molecular
  • Molecular Structure
  • Motion
  • Particle Size
  • Rotaxanes / chemical synthesis*
  • Rotaxanes / chemistry

Substances

  • Dendrimers
  • Macromolecular Substances
  • Rotaxanes
  • Copper