Molecular Borromean Rings
Kelly S. Chichak,1
Stuart J. Cantrill,1
Anthony R. Pease,1
Sheng-Hsien Chiu,1
Gareth W. V. Cave,2
Jerry L. Atwood,2
J. Fraser Stoddart1*
The realization of the Borromean link in a wholly synthetic molecular form is reported. The self-assembly of this link, which is topologically achiral, from 18 components by the template-directed formation of 12 imine and 30 dative bonds, associated with the coordination of three interlocked macrocycles, each tetranucleating and decadentate overall, to a total of six zinc(II) ions, is near quantitative. Three macrocycles present diagonally in pairs, six exo-bidentate bipyridyl and six endo-diiminopyridyl ligands to the six zinc(II) ions. The use, in concert, of coordination, supramolecular, and dynamic covalent chemistry allowed the highly efficient construction, by multiple cooperative self-assembly processes, of a nanoscale dodecacation with an approximate diameter of 2.5 nanometers and an inner chamber of volume 250 Å3, lined with 12 oxygen atoms.
1 Department of Chemistry and Biochemistry and the California NanoSystems Institute, University of California, Los Angeles, 405 Hilgard Avenue, Los Angeles, CA 90095, USA.
2 Department of Chemistry, University of Missouri-Columbia, MO 65211, USA.
* To whom correspondence should be addressed. E-mail: stoddart{at}chem.ucla.edu
