Porous Molecular Capsules as Non‐Polymeric Transducers of Mechanical Forces to Mechanophores. Issue 7 (7th January 2020)

• Record Type: Journal Article
• Authors: Jędrzejewska, Hanna; Wielgus, Ewelina; Kaźmierski, Sławomir; Rogala, Halina; Wierzbicki, Michał; Wróblewska, Aneta; Pawlak, Tomasz; Potrzebowski, Marek J.; Szumna, Agnieszka
• Is Part Of: Chemistry. Volume 26:Issue 7(2020)
• Page Start: 1558
• Page End: 1566
• Publication Date: 2020-01-07
• Subjects: mechanochemistry -- solid-state NMR spectroscopy -- solid-phase synthesis -- solvent-free MALDI -- supramolecular chemistry; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201904024
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Mechanical grinding/milling can be regarded as historically the first technology for changing the properties of matter. Mechanically activated molecular units (mechanophores) can be present in various structures: polymers, macromolecules, or small molecules. However, only polymers have been reported to effectively transduce energy to mechanophores, which induces breakage of covalent bonds. In this paper, a second possibility is presented—molecular capsules as stress‐sensitive units. Mechanochemical encapsulation of fullerenes in cystine‐based covalent capsules indicates that complexation takes place in the solid state, despite the fact that the capsules do not possess large enough entrance portals. By using a set of solvent‐free MALDI (sf‐MALDI) and solid‐state NMR (ss‐NMR) experiments, it has been proven that encapsulation proceeds during milling and in this process hydrazones and disulfides get activated for breakage, exchange, and re‐forming. The capsules are porous and therefore prone to collapse under solvent‐free conditions and their conformational rigidity promotes the collapse by the breaking of covalent bonds. Abstract : Breaking bonds : Covalent molecular capsules can serve as stress‐sensitive units, which effectively transduce mechanical energy, inducing breakage of covalent bonds. Encapsulation of fullerenes takes place in the solid state during neat milling and mechanophores (hydrazones and disulfides) get activated for breakage, exchange, and re‐forming.