Jump to main content
Jump to site search

Issue 7, 2011
Previous Article Next Article

Degenerate [2]rotaxanes with electrostatic barriers

Author affiliations

Abstract

A synthetic approach to the preparation of [2]rotaxanes (1–5·6PF6) incorporating bispyridinium derivatives and two 1,5-dioxynaphthalene (DNP) units situated in the rod portions of their dumbbell components that are encircled by a single cyclobis(paraquat-p-phenylene) tetracationic (CBPQT4+) ring has been developed. Since the π-electron-deficient bispyridinium units are introduced into the dumbbell components of the [2]rotaxanes 1–5·6PF6, there are Coulombic charge–charge repulsions between these dicationic units and the CBPQT4+ ring in the [2]rotaxanes. Thus, the CBPQT4+ rings in the degenerate [2]rotaxanes exhibit slow shuttling between two DNP recognition sites on the 1H NMR time-scale on account of the electrostatic barrier posed by the bispyridinium units, as demonstrated by variable-temperature 1H NMR spectroscopy. Electrochemical experiments carried out on the [2]rotaxanes 1·6PF6 and 2·6PF6 indicate that the one-electron reduced bipyridinium radical cation in the dumbbell components of the [2]rotaxanes serves as an additional recognition site for the two-electron reduced CBPQT2(˙+) diradical cationic ring. Under appropriate conditions, the ring components in the degenerate rotaxanes 1·6PF6 and 2·6PF6 can shuttle along the recognition sites – two DNP units and one-electron reduced bipyridinium radical cation – under redox control.

Graphical abstract: Degenerate [2]rotaxanes with electrostatic barriers

Back to tab navigation

Supplementary files

Publication details

The article was received on 27 Oct 2010, accepted on 24 Dec 2010 and first published on 23 Feb 2011


Article type: Paper
DOI: 10.1039/C0OB00937G
Citation: Org. Biomol. Chem., 2011,9, 2240-2250
  •   Request permissions

    Degenerate [2]rotaxanes with electrostatic barriers

    H. Li, Y. Zhao, A. C. Fahrenbach, S. Kim, W. F. Paxton and J. F. Stoddart, Org. Biomol. Chem., 2011, 9, 2240
    DOI: 10.1039/C0OB00937G

Search articles by author

Spotlight

Advertisements