Speed-Controlled Molecular Shuttles

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Title:Speed-Controlled Molecular Shuttles
Creators:
Bělohradský, Martin
Elizarov, Arkadij M.
Stoddart, J. Fraser
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 67, 11, pp. 1719-1728
Uncontrolled Keywords:Post-assembly covalent modification, Molecular shuttle, Molecular recognition, Molecular machines, Dynamic NMR spectroscopy, Crown ethers, Bipyridinium salts, Rotaxanes

Abstract

Five potential molecular shuttles based on degenerate [2]rotaxanes - wherein the ring component is a bis-1,4-phenylene[34]crown-10 and the dumbbell components are terminated by tetraarylmethane (slippage) stoppers and contain two identical bipyridinium recognition sites and a central 1,3-phenylene unit carrying a CH<sub>2</sub>OR (R = Me, Et, Ph, i-Pr, and <i>t</i>-Bu) substituent on its C-5 position - have been prepared by acylating the parent hydroxymethyl derivative with the appropriate reagents. Dynamic <sup>1</sup>H NMR spectroscopy, carried out on these five potential molecular shuttles in CD<sub>3</sub>CN solutions, has revealed average Gibbs energy barriers to shuttling of 11.5, 12.0, 14.6, and 14.8 kcal mol<sup>-1</sup> for the [2]rotaxanes where R = Me, Et, i-Pr, and Ph, respectively. For the [2]rotaxane where R = <i>t</i>-Bu, the Gibbs energy barrier to shuttling must exceed 17.2 kcal mol<sup>-1</sup>. <p>

Title:Speed-Controlled Molecular Shuttles
Creators:
Bělohradský, Martin
Elizarov, Arkadij M.
Stoddart, J. Fraser
Uncontrolled Keywords:Post-assembly covalent modification, Molecular shuttle, Molecular recognition, Molecular machines, Dynamic NMR spectroscopy, Crown ethers, Bipyridinium salts, Rotaxanes
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:67
Number:11
Page Range:pp. 1719-1728
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc20021719UNSPECIFIED
ID Code:2029
Item Type:Article
Deposited On:06 Feb 2009 17:14
Last Modified:06 Feb 2009 16:15

Citation

Bělohradský, Martin; Elizarov, Arkadij M.; Stoddart, J. Fraser (2002) Speed-Controlled Molecular Shuttles. Collection of Czechoslovak Chemical Communications, 67 (11). pp. 1719-1728. ISSN 0010-0765

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