This award in the Inorganic, Bioinorganic, and Organometallic Program supports research on aromatic metallacycles by Dr. John R. Bleeke, Department of Chemistry, Washington University. Late transition metals, such as Ir, Os, Rh, and Pt, would be incorporated into carbon rings of various sizes to form compounds with aromatic character. Other heteroatoms, such as oxygen, sulfur, nitrogen and phosphorus, would also be included in the rings to form a wide variety of compounds of a fundamentally new type. Using methodology developed to synthesize "iridabenzene", compounds such as metallapyridine and metallafuran would be prepared. The reactivity of the metallabenzenes would be explored, including their behavior in cycloaddition reactions and electrophilic and nucleophilic substitution reactions. Synthesis of larger pi-systems would be attempted. Calculational modeling would be used to interpret the degree of aromaticity in the compounds, to help understand their electronic and magnetic properties, and to predict their reactivity. %%% Aromatic compounds predominantly formed by rings of carbon atoms form a large class of organic compounds. In this study, Dr. Bleeke will synthesize analogous compounds in which carbon is replaced by a metal. The extended bonding systems characteristic of aromatic compounds would be maintained, but altered. Bleeke will determine the new bonding and reactivity characteristics of these compounds. In addition, he will attempt to prepare other analogous compounds in which oxygen, phosphorus, and sulfur are also included in the rings, and to make larger aromatic compounds of this type. The results of this fundamental study may be helpful to researchers attempting to construct conducting or semiconducting polymers which contain both metals and organic portions.
