Radical-Pairing Interactions in a Molecular Switch Evidenced by Ion Mobility Spectrometry and Infrared Ion Spectroscopy

Emeline Hanozin, Benoit Mignolet, Jonathan Martens, Giel Berden, Damien Sluysmans, Anne Sophie Duwez, J. Fraser Stoddart, Gauthier Eppe, Jos Oomens, Edwin De Pauw, Denis Morsa*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

The digital revolution sets a milestone in the progressive miniaturization of working devices and in the underlying advent of molecular machines. Foldamers involving mechanically entangled components with modular secondary structures are among the most promising designs for molecular switch-based applications. Characterizing the nature and dynamics of their intramolecular network following the application of a stimulus is the key to their performance. Here, we use non-dissociative electron transfer as a reductive stimulus in the gas phase and probe the consecutive co-conformational transitions of a donor-acceptor oligorotaxane foldamer using electrospray mass spectrometry interfaced with ion mobility and infrared ion spectroscopy. A comparison of collision cross section distributions for analogous closed-shell and radical molecular ions sheds light on their respective formation energetics, while variations in their respective infrared absorption bands evidence changes in intramolecular organization as the foldamer becomes more compact. These differences are compatible with the advent of radical-pairing interactions.

Original languageEnglish (US)
Pages (from-to)10049-10055
Number of pages7
JournalAngewandte Chemie - International Edition
Volume60
Issue number18
DOIs
StatePublished - Apr 26 2021

Funding

The research leading to these results has received funding from LASERLAB‐EUROPE (grant agreement no. 654148, European Union's Horizon 2020 research and innovation program). The authors gratefully acknowledge the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) for the support of the FELIX Laboratory. Computational resources have been provided by the Consortium des Équipements de Calcul Intensif (CÉCI), funded by the Fonds de la Recherche Scientifique de Belgique (F.R.S.‐FNRS) under Grant No. 2.5020.11 and by the Walloon Region. The authors thank Dr. Zhixue Zhu for the synthesis of the oligorotaxane foldamer. J.F.S. thanks Northwestern University for its continuing support of his research. Prof. Loïc Quinton, Prof. Bernard Leyh, Dr. Johann Far and Dr. Christopher Kune (University of Liège, Belgium) are acknowledged for discussions on the results. D.S. is a Post‐doctoral researcher of the FRS‐FNRS. The research leading to these results has received funding from LASERLAB-EUROPE (grant agreement no. 654148, European Union's Horizon 2020 research and innovation program). The authors gratefully acknowledge the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) for the support of the FELIX Laboratory. Computational resources have been provided by the Consortium des ?quipements de Calcul Intensif (C?CI), funded by the Fonds de la Recherche Scientifique de Belgique (F.R.S.-FNRS) under Grant No. 2.5020.11 and by the Walloon Region. The authors thank Dr. Zhixue Zhu for the synthesis of the oligorotaxane foldamer. J.F.S. thanks Northwestern University for its continuing support of his research. Prof. Lo?c Quinton, Prof. Bernard Leyh, Dr. Johann Far and Dr. Christopher Kune (University of Li?ge, Belgium) are acknowledged for discussions on the results. D.S. is a Post-doctoral researcher of the FRS-FNRS.

Keywords

  • donor-acceptor foldamer
  • electron transfer
  • infrared spectroscopy
  • ion mobility
  • mass spectrometry

ASJC Scopus subject areas

  • General Chemistry
  • Catalysis

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