Reactivity of Ruthenium(III) Heteroatom-Carbene Complexes

The chemistry of transition-metal carbene complexes is of interest because they are believed to be active intermediates for carbene insertions into C=C bonds. Although a variety of ruthenium(II) heteroatom-carbene complexes in the form such as [Ru=C(OR)R'] have been synthesized, they show no reactivity towards olefin cyclopropanation. Recently the investigators have discovered that ruthenium(II) carbene complexes bearing polypyridines are unstable towards ligand substitution on irradiation or oxidation, and they believe that active ruthenium(III) carbene species are generated in the course of the reactions. This project will study the photochemical and electrochemical reactions associated with a series of ruthenium heteroatom carbene complexes bearing oxidatively robust polypyridine ligands, and investigate the possibility of using ruthenium(III) carbene species for practical and efficient catalysts in olefin cyclopropanation. These studies should provide a new approach for catalytic cyclopropanation of olefins.