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DDC: 540 × Type: article × search.filters.applied.f.series: Angewandte Chemie - International Edition 60 (2021), Nr. 24 × WGL Institute: DWI ×

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    Multicolor Mechanofluorophores for the Quantitative Detection of Covalent Bond Scission in Polymers
    (Weinheim : Wiley-VCH, 2021) Baumann, Christoph; Stratigaki, Maria; Centeno, Silvia P.; Göstl, Robert
    The fracture of polymer materials is a multiscale process starting with the scission of a single molecular bond advancing to a site of failure within the bulk. Quantifying the bonds broken during this process remains a big challenge yet would help to understand the distribution and dissipation of macroscopic mechanical energy. We here show the design and synthesis of fluorogenic molecular optical force probes (mechanofluorophores) covering the entire visible spectrum in both absorption and emission. Their dual fluorescent character allows to track non-broken and broken bonds in dissolved and bulk polymers by fluorescence spectroscopy and microscopy. Importantly, we develop an approach to determine the absolute number and relative fraction of intact and cleaved bonds with high local resolution. We anticipate that our mechanofluorophores in combination with our quantification methodology will allow to quantitatively describe fracture processes in materials ranging from soft hydrogels to high-performance polymers. © 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH
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    Mechanochemical Release of Non-Covalently Bound Guests from a Polymer-Decorated Supramolecular Cage
    (Weinheim : Wiley-VCH, 2021) Küng, Robin; Pausch, Tobias; Rasch, Dustin; Göstl, Robert; Schmidt, Bernd M.
    Supramolecular coordination cages show a wide range of useful properties including, but not limited to, complex molecular machine-like operations, confined space catalysis, and rich host–guest chemistries. Here we report the uptake and release of non-covalently encapsulated, pharmaceutically-active cargo from an octahedral Pd cage bearing polymer chains on each vertex. Six poly(ethylene glycol)-decorated bipyridine ligands are used to assemble an octahedral PdII6(TPT)4 cage. The supramolecular container encapsulates progesterone and ibuprofen within its hydrophobic nanocavity and is activated by shear force produced by ultrasonication in aqueous solution entailing complete cargo release upon rupture, as shown by NMR and GPC analyses. © 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH