New Scientist reports that three interlocking molecular Borromean rings were self assembled by a team led by Fraser Stoddart. Stoddart told New Scientist his work on Borromean rings was inspired in part by "their potential to be turned into some of the smallest possible machines and switches you can design at the molecular level." Jay Siegel, a chemist at the University of Zurich, agreed that "Chains and links are important for making gears and switching devices".
The New Scientist also reports that:
Computer modelling played a vital role in the molecule's design. "Not one atom changed its type or place in the molecular structure between going from the computer to the laboratory. This experience is still an extremely rare one," says Stoddart, whose results are published in Science.
Abstract from Science magazine:
Science, Vol 304, Issue 5675, 1308-1312 , 28 May 2004
Molecular Borromean Rings
Kelly S. Chichak, Stuart J. Cantrill, Anthony R. Pease, Sheng-Hsien Chiu, Gareth W. V. Cave, Jerry L. Atwood, J. Fraser Stoddart
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.