A mechanically interlocked [3]rotaxane as a light-harvesting antenna: synthesis, characterization, and intramolecular energy transfer

Chemistry. 2009;15(14):3585-94. doi: 10.1002/chem.200802228.

Abstract

A mechanically interlocked light-harvesting system [3]rotaxane A has been synthesized in high yield through Cu(I)-catalyzed azide-alkyne cycloaddition; the hexyl-substituted truxene units are introduced into the wheels as donors and an oligo(para-phenylenevinylene) (OPV) unit into the axis as the acceptor. The structure and the purity of [3]rotaxane A were confirmed by (1)H and (13)C NMR spectroscopy and ESI HRMS. The azide-alkyne cycloaddition is demonstrated to be an efficient stoppering method in the synthesis of the rotaxane containing dibenzo[24]crown-8 and dibenzyl ammonium units. Detailed steady-state UV/Vis absorption, photoluminescent, and time-resolved fluorescence spectroscopy were performed to investigate the photophysical properties of [3]rotaxane A and its reference compounds in solution and as thin films. Even in dilute solution, efficient energy transfer from the truxene-functionalized wheels to the OPV-based axis, through the dibenzo[24]crown-8 and dibenzyl ammonium interaction, is observed in [3]rotaxane A. The unique topology of [3]rotaxane A not only efficiently promotes the intramolecular energy-transfer process, but also prevents intermolecular aggregation in the solid state. The new antenna system opens up the possibility of controllable light-harvesting molecular machines or other optoelectronic devices on the nanometer scale.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkynes / chemical synthesis
  • Alkynes / chemistry
  • Azides / chemical synthesis
  • Azides / chemistry
  • Catalysis
  • Copper / chemistry
  • Cyclization
  • Energy Transfer*
  • Fluorescent Dyes / chemical synthesis*
  • Fluorescent Dyes / chemistry
  • Light
  • Photochemistry
  • Rotaxanes / chemical synthesis*
  • Rotaxanes / chemistry
  • Spectrometry, Mass, Electrospray Ionization

Substances

  • Alkynes
  • Azides
  • Fluorescent Dyes
  • Rotaxanes
  • Copper