Catalysis at Metal-Metal Bonds

From laboratory-scale syntheses of bioactive compounds to industrial-scale processes that deliver basic chemicals, transition metal catalysis plays a key role in how molecules are built in the modern world. With a few notable exceptions, efforts to discover new molecular transition metal catalysts have focused on coordination compounds that contain a single metal center in their active sites. In principle, polynuclear catalysts might exhibit unique properties by binding substrates or delocalizing redox activity across multiple metal centers. Complexes containing direct metal–metal bonds are particularly well-suited to capitalize on these cooperativity effects due to the enforced proximity of the metals and the strong electronic coupling between them. On a fundamental level, such systems would provide mechanistic models for the multimetallic processes that are proposed to take place at metallocofactors in enzymes and on the surfaces of heterogeneous catalysts.

The overarching goal of our research program is to develop new classes of well-defined synthetic catalysts that feature metal–metal bonds as active sites. Recently, we have developed a naphthyridine–diimine ligand that was used to prepare dinuclear complexes of mid-to-late first-row transition metals. The redox-active nature of these ligands imparts rich redox chemistry to these complexes, enabling an array of multielectron oxidation and reduction reactions. The applications of these complexes as catalysts for organic reactions will be presented.