Sliding-Ring Catenanes

Isurika R. Fernando, Marco Frasconi, Yilei Wu, Wei Guang Liu, Michael R Wasielewski, William A. Goddard, J. Fraser Stoddart

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Template-directed protocols provide a routine approach to the synthesis of mechanically interlocked molecules (MIMs), in which the mechanical bonds are stabilized by a wide variety of weak interactions. In this Article, we describe a strategy for the preparation of neutral [2]catenanes with sliding interlocked electron-rich rings, starting from two degenerate donor-acceptor [2]catenanes, consisting of a tetracationic cyclobis(paraquat-p-phenylene) cyclophane (CBPQT4+) and crown ethers containing either (i) hydroquinone (HQ) or (ii) 1,5-dioxynaphthalene (DNP) recognition units and carrying out four-electron reductions of the cyclophane components to their neutral forms. The donor-acceptor interactions between the CBPQT4+ ring and both HQ and DNP units present in the crown ethers that stabilize the [2]catenanes are weakened upon reduction of the cyclophane components to their radical cationic states and are all but absent in their fully reduced states. Characterization in solution performed by UV-vis, EPR, and NMR spectroscopic probes reveals that changes in the redox properties of the [2]catenanes result in a substantial decrease of the energy barriers for the circumrotation and pirouetting motions of the interlocked rings, which glide freely through one another in the neutral states. The solid-state structures of the fully reduced catenanes reveal profound changes in the relative dispositions of the interlocked rings, with the glycol chains of the crown ethers residing in the cavities of the neutral CBPQT0 rings. Quantum mechanical investigations of the energy levels associated with the four different oxidation states of the catenanes support this interpretation. Catenanes and rotaxanes with sliding rings are expected to display unique properties.

Original languageEnglish
Pages (from-to)10214-10225
Number of pages12
JournalJournal of the American Chemical Society
Volume138
Issue number32
DOIs
Publication statusPublished - Aug 17 2016

Fingerprint

Catenanes
Crown ethers
Crown Ethers
Electrons
Energy barriers
Glycols
Electron energy levels
Paramagnetic resonance
Nuclear magnetic resonance
Rotaxanes
Oxidation
Molecules
Paraquat
Oxidation-Reduction

ASJC Scopus subject areas

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

Cite this

Fernando, I. R., Frasconi, M., Wu, Y., Liu, W. G., Wasielewski, M. R., Goddard, W. A., & Stoddart, J. F. (2016). Sliding-Ring Catenanes. Journal of the American Chemical Society, 138(32), 10214-10225. https://doi.org/10.1021/jacs.6b04982

Sliding-Ring Catenanes. / Fernando, Isurika R.; Frasconi, Marco; Wu, Yilei; Liu, Wei Guang; Wasielewski, Michael R; Goddard, William A.; Stoddart, J. Fraser.

In: Journal of the American Chemical Society, Vol. 138, No. 32, 17.08.2016, p. 10214-10225.

Research output: Contribution to journalArticle

Fernando, IR, Frasconi, M, Wu, Y, Liu, WG, Wasielewski, MR, Goddard, WA & Stoddart, JF 2016, 'Sliding-Ring Catenanes', Journal of the American Chemical Society, vol. 138, no. 32, pp. 10214-10225. https://doi.org/10.1021/jacs.6b04982
Fernando IR, Frasconi M, Wu Y, Liu WG, Wasielewski MR, Goddard WA et al. Sliding-Ring Catenanes. Journal of the American Chemical Society. 2016 Aug 17;138(32):10214-10225. https://doi.org/10.1021/jacs.6b04982
Fernando, Isurika R. ; Frasconi, Marco ; Wu, Yilei ; Liu, Wei Guang ; Wasielewski, Michael R ; Goddard, William A. ; Stoddart, J. Fraser. / Sliding-Ring Catenanes. In: Journal of the American Chemical Society. 2016 ; Vol. 138, No. 32. pp. 10214-10225.
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