With the support of the Organic and Macromolecular Chemistry Program, Professor Jay S. Siegel, of the Department of Chemistry at the University of Calfornia, San Diego, is studying the stereochemistry of nanoscale molecules. Professor Siegel is carrying out the synthesis of molecules representing unusual topological stereoisomers, including chiral catenanes, enantiopure D3 trefoil knots, and Borromean links. As these molecules are prepared, properties arising from their unusual structures, including highly efficient fluorescence emission, are studied. The synthesis of bowl-shaped polycyclic aromatic hydrocarbons similar to corranulene and the dynamics of their bowl-to-bowl inversion are also under investigation. Chiral derivatives of these structures will be prepared and their chiroptical and molecular recognition properties, including affinities for ions, gases, and polar molecules, will be studied. Liquid crystalline and dendrimeric corranulene-based structures will also be prepared.
Molecular design, coupled with chemical synthesis, offers the best approach to the development of truly new molecular materials. Nanoscale molecules represent a relatively unexplored family of synthetically designed chemical structures, intermediate between classical natural products and biomolecules and polymers. Design principles for this area are still in their infancy, and the three-dimensional structures (stereochemistry) of these compounds remain fascinating. Professor Jay S. Siegel, of the Department of Chemistry at the University of California at San Diego, applies experimental, theoretical, and computational techniques to the synthesis and stereochemical elucidation of nanoscale molecules representing a variety of classical stereochemistries which are unrepresented by synthetic organic chemical systems, including trefoil knots and Borromean links.