ORGN 256 |
| The molecular construction of the Borromean Ring (BR) topology has long been a formidable synthetic challenge as they consist of three mutually interlocked, and noncatenated rings. The BR topology can be viewed as a three-ring system, as described in knot theory, with the sole requirement that the scission of any one of the rings destroys the unique union of the three. On the assumption that the construction of BRs from small building blocks can be realized by appealing to constitutional dynamic chemistry protocols, we have successfully achieved the complete molecular construction of the BR topology from 18 individual components under strict dynamic covalent, coordinative, and supramolecular control. The dynamic construction of the BR topology is predicated on the ability to control the placement of 12 organic fragments around 6 transition metals in near quantitative yields. In this manner, six transition metals spatially preorganize six tridentate and six bidentate ligands such they preferentially react and form molecular Borromean Rings in a single step in yields of greater than 95%. From a design point of view, in a bottom-up sense at least, this molecular BR topology provides a unique nanoscale 3-dimensional scaffold into which unique features (e.g., electroactive, photoactive, and chiro-optical) can be imbedded at will. Recent successes in the construction and modification of Borromean Ring compounds will be presented.
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Molecular Recognition and Materials
1:00 PM-4:40 PM, Monday, 29 August 2005 Washington DC Convention Center -- 201, Oral
Division of Organic Chemistry |
