Our Journey to the Chemistry of Metallabenzynes

This personal account summarizes our work on the chemistry of transition-metal-containing metallabenzynes, organometallic compounds derived from formal replacement of a C atom in benzyne by an isolobal transition-metal fragment. Metallabenzynes with osmium and rhenium have been synthesized and well characterized. They have aromatic character on the basis of the criteria of reactivity, geometry, aromatic stabilization energy, and magnetic properties. They can undergo typical reactions of aromatic systems (e.g., electrophilic substitution reactions) and organometallic complexes (e.g., reductive elimination reactions to form carbene complexes).