Viologen Tweezers to Probe the Force of Individual Donor-Acceptor π-Interactions

Damien Sluysmans*, Long Zhang, Xuesong Li, Amine Garci, J. Fraser Stoddart, Anne Sophie Duwez

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Donor-acceptor (DA) π-interactions are weak attractive forces that are exploited widely in molecular and supramolecular chemistry. They have been characterized extensively by ensemble techniques, providing values for their energies that are useful for the design of soft materials. For implementation of motions or operations based on these DA π-interactions in wholly synthetic molecular machines, the mechanical strength and force associated with their out-of-equilibrium performance are the key parameters, in addition to their energies obtained at thermodynamic equilibrium. In this context, we have used single-molecule force spectroscopy as a nonequilibrium technique to determine the mechanical strength of individual DA π-interactions in solution. We designed and synthesized a molecular tweezer that is able to encapsulate π-donors and also demonstrated a precise opening extension. The mechanical breaking of the noncovalent interactions between viologen units - π-acceptors commonly employed in mechanically interlocked molecules - and several π-donors afforded a characteristic force-distance signature, revealing the opening of individual viologen tweezers with an unambiguous extension. Single-tweezer host-exchange experiments performed in situ demonstrated the sensitivity of the technique. This simple design could be exploited in quantifying the force of a large range of weak noncovalent bonding interactions as well as the potential work that molecular machines can generate at the single-molecule level.

Original languageEnglish (US)
Pages (from-to)21153-21159
Number of pages7
JournalJournal of the American Chemical Society
Issue number50
StatePublished - Dec 16 2020

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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