Display options
Cite
Chiu SH, Stoddart JF. Reversing a rotaxane recognition motif: threading oligoethylene glycol derivatives through a dicationic cyclophane. J Am Chem Soc. 2002;124(16):4174-5doi: 10.1021/ja012654t.
Chiu, S. H., & Stoddart, J. F. (2002). Reversing a rotaxane recognition motif: threading oligoethylene glycol derivatives through a dicationic cyclophane. Journal of the American Chemical Society, 124(16), 4174-5. https://doi.org/10.1021/ja012654t
Chiu, Sheng-Hsien, and Stoddart, J Fraser. "Reversing a rotaxane recognition motif: threading oligoethylene glycol derivatives through a dicationic cyclophane." Journal of the American Chemical Society vol. 124,16 (2002): 4174-5. doi: https://doi.org/10.1021/ja012654t
Chiu SH, Stoddart JF. Reversing a rotaxane recognition motif: threading oligoethylene glycol derivatives through a dicationic cyclophane. J Am Chem Soc. 2002 Apr 24;124(16):4174-5. doi: 10.1021/ja012654t. PMID: 11960422.
Copy Download .nbib Format: NLM
Share it on

J Am Chem Soc. 2002 Apr 24;124(16):4174-5. doi: 10.1021/ja012654t.

Reversing a rotaxane recognition motif: threading oligoethylene glycol derivatives through a dicationic cyclophane.

Journal of the American Chemical Society

Sheng-Hsien Chiu, J Fraser Stoddart

Affiliations

  1. Department of Chemistry and Biochemistry, University of California, Los Angeles, 405 Hilgard Avenue, Los Angeles, California 90095-1569, USA.

PMID: 11960422 DOI: 10.1021/ja012654t

Abstract

An already well-established recognition motif-namely one in which the NH2+ centers in the rod sections of the dumbbell components of rotaxanes are encircled by macrocyclic polyether components-has been turned simultaneously outside-in and inside-out, a fact that has been proved beyond any doubt by the stoppering of both ends of a [2]pseudorotaxane to give a stable [2]rotaxane. The [2]pseudorotaxane is formed in nitromethane when a benzylic dibromide, obtained after reacting an excess of 1,4-bis(bromomethyl)benzene with hexaethylene glycol, is added to an equimolar amount of a dicationic cyclophane in which two -CH2OCH2- chains link a pair of dibenzylammonium ions through the para positions on their phenyl rings. When the [2]pseudorotaxane is reacted in nitromethane with triphenylphosphine, a [2]rotaxane and the corresponding free dumbbell compound are isolated in 58 and 31% yields, respectively. The structure of the [2]rotaxane is established by using mass spectrometry (FABMS and ESMS) and NMR (1H and 13C) spectroscopy in nitromethane-d3. The [2]rotaxane exhibits quite dramatic changes in the 1H chemical shifts of the signals for its CH2N+ and CH2O protons compared with those in the free dumbbell compound. The 1H NMR spectrum of the [2]pseudorotaxane shows many similar features. Titration experiments with three of the six different CH2O probes give an average Ka value of 2900 +/- 750 M-1 in nitromethane-d3. The new recognition motif for the template-directed synthesis of rotaxanes can now be exploited at both the molecular and macromolecular levels of structure with numerous potential applications in sight.

Publication Types