How to Design Organometallic “Electron-Reservoirs”

Abstract

Abstract Two essential facets of transition metal organometallic compounds are (i) their ability to undergo transformations of organic and inorganic species at the metal and (ii) the ease of redox changes induced by the metal. This Comment indicates the potential of this second aspect and how organometallics may be designed and used to promote electron transfer (ET). Inexpensive, easily available organometallic electron-reservoirs can conveniently effect a variety of stoichiometric and catalytic ET processes. The salt effect and the activation of dioxygen are especially under our scrutiny in stoichiometric reactions. Catalytic ET involves redox catalysis of electrochemical reactions (the catalyst lowers the overpotential) and electro-catalysis of organometallic reactions (ligand substitution, decomplexation, isomerization, chelation, insertion). These processes can be effected using (instead of an electrode) iron sandwich compounds: the electron-deficient ferricinium Cp2Fe+ (17 valence electrons) for oxidations and the electron-reservoir compound CpFeIC6Me6(19 valence electrons) for reductions.