Jump to main content
Jump to site search

Issue 24, 2018
Previous Article Next Article

Reversible mechanofluorochromism of aniline-terminated phenylene ethynylenes

Author affiliations

Abstract

Seven three-ring phenylene-ethynylene (PE) structural analogs, differing only in the lengths of alkyl chains on terminal aniline substituents, show 50–62 nm bathochromic shifts in emission maxima in response to mechanical force (mechanofluorochromism, MC). These shifts are fully reversible with heat or solvent fuming. Shearing of these solids yields a transition from green-emitting crystalline phases to orange-emitting amorphous phases as established by differential scanning calorimetry and X-ray diffraction. Molecules with shorter alkyl chain lengths required higher temperatures to recover the hypsochromically shifted crystalline phases after grinding, while the recovery with chain lengths longer than butyl occurred at room temperature. In addition to this structure-dependent thermochromism, these compounds retain their MC properties in polymer hosts to various extents. The crystalline phases of these materials have PE chromophores that are twisted due to non-covalent perfluoroarene–arene (ArF–ArH) interactions involving perfluorophenyl pendants and the terminal rings of the PE chromophore, resulting in interrupted conjugation and an absence of chromophore aggregation. The MC behavior of an analog without the perfluoroarene rings is severely attenuated. This work demonstrates the general utility of twisted PEs as stimuli-responsive moieties and reveals clear structure–property relationships regarding the effects of alkyl chain length on these materials.

Graphical abstract: Reversible mechanofluorochromism of aniline-terminated phenylene ethynylenes

Back to tab navigation

Supplementary files

Publication details

The article was received on 28 Feb 2018, accepted on 23 May 2018 and first published on 24 May 2018


Article type: Edge Article
DOI: 10.1039/C8SC00980E
Citation: Chem. Sci., 2018,9, 5415-5426
  • Open access: Creative Commons BY license
  •   Request permissions

    Reversible mechanofluorochromism of aniline-terminated phenylene ethynylenes

    S. A. Sharber, K. Shih, A. Mann, F. Frausto, T. E. Haas, M. Nieh and S. W. Thomas, Chem. Sci., 2018, 9, 5415
    DOI: 10.1039/C8SC00980E

    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements