ORGN 200 |
| The molecular construction of the Borromean Ring (BR) topology has long been a formidable synthetic challenge as it consist of three mutually interlocked, yet noncatenated rings. The complete molecular construction of the BR topology has been achieved successfully 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 ligands around six transition metals. Stabilized by combinations of 12 Π– Π stacking interactions and 30 dative bonds, six tridentate and six bidentate ligands are spatially preorganized around six transition metals, such that they react preferentially 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 symmetrical, nanoscale three-dimensional scaffold into which unique features (e.g., electroactive, photoactive, and chiro-optical) can be imbedded at will. Taking advantage of the ability to preorganize six metal ions spatially and symmetrically, other metals with interesting redox properties were used to construct (Box) more Borromeates. Additionally, conditions were used in which metals were mixed and led to the formation of another topological entity, known as King Solomon's Link. This unexpected result raises the question of what other possible entities are within reach by subtle modifications to the conditions employed in the synthesis of the Borromean Rings.
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Molecular Recognition and Self-Assembly
8:00 AM-12:00 PM, Monday, 27 March 2006 Georgia World Congress Center -- C302, Oral
Division of Organic Chemistry |
