Jump to main content
Jump to site search


Mechanically induced pyrogallol[4]arene hexamer assembly in the solid state extends the scope of molecular encapsulation

Author affiliations

Abstract

Pyrogallol[4]arene hexamers are hydrogen-bonded molecular capsules of exceptional kinetic stability that can entrap small molecule guests indefinitely, without exchange, at ambient temperatures. Here, we report on the use of a ball mill to induce self-assembly of the capsule components and the guests in the solid state. Stoichiometric amounts of pyrogallol[4]arene and a guest, which can be an arene, alkane, amine, or carboxylic acid, were milled at 30 Hz for fixed durations, dissolved, and characterization by NMR. Most of the resulting encapsulation complexes were kinetically stable but thermodynamically unstable in solution, and the yield of their formation correlates with the duration of the milling and is related to the structures of guest and host. This method extends the scope of molecular encapsulation, as demonstrated by the preparation of kinetically trapped encapsulation complexes of [2.2]paracyclophane, for which we could find no other method of preparation. To gain mechanistic insights into the solid-state assembly process, we characterized the milled powders using 13C CP-MAS NMR, we studied the effects of changing the alkane domain of the host, and we examined how dissolution conditions impact on the distribution of observed encapsulation complexes once in solution. The results support a mechanism comprising mechanically induced solid-state reorganization to produce a mixture rich in nearly or fully assembled guest-filled capsules.

Graphical abstract: Mechanically induced pyrogallol[4]arene hexamer assembly in the solid state extends the scope of molecular encapsulation

Back to tab navigation

Supplementary files

Publication details

The article was received on 01 Sep 2017, accepted on 25 Sep 2017 and first published on 25 Sep 2017


Article type: Edge Article
DOI: 10.1039/C7SC03821F
Citation: Chem. Sci., 2017, Advance Article
  • Open access: Creative Commons BY-NC license
  •   Request permissions

    Mechanically induced pyrogallol[4]arene hexamer assembly in the solid state extends the scope of molecular encapsulation

    Sara N. Journey, K. L. Teppang, C. A. Garcia, S. A. Brim, D. Onofrei, J. B. Addison, G. P. Holland and B. W. Purse, Chem. Sci., 2017, Advance Article , DOI: 10.1039/C7SC03821F

    This article is licensed under a Creative Commons Attribution-NonCommercial 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 and it is not used for commercial purposes.

    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