Redox non-innocent ligands have gained much attention in the past several years, giving both redox active and inactive metal centers access to additional non-d orbital electrons. However, most organic non-innocent ligands are capable of shuttling at most 2 electrons to the central metal, generally limiting the complex’s efficiency in multi-electron catalysis (ex. water oxidation (4 e-), dinitrogen reduction (6 e-), CO2 reduction to methane (8 e-)), as well as in energy storage applications. Herein, we will describe our recent efforts in developing new molecular platforms bearing redox active “metallo-ligands” (ML) bound through a resonance linker (X) to a central main group atom (E) with the general structure, E(XML)n (n = 2-4), capable of delivering and storing multiple electrons. Sterically shielded encapsulated first-row metals, such as V, Cr, or Mn metallocenes, capable of accessing multiple oxidation states are used as ML fragments, with N and O acting as typical resonance linkers (X), and Lewis acidic (Ca, B, Al) or basic (P, As) elements comprising the main group (E) centers. Metal-main group communication (ML→E) through resonance linkers (X) has been demonstrated1 and this concept will be used to push the realm of non-innocent ligands beyond the 2 e- limit. “Wiring” multiple ML fragments to E will allow for the facile delivery/uptake of multiple electrons at the focal E providing access to difficult multi-electron catalysis with small molecules at the Lewis acidic or basic center (E). This platform may also act as an ideal candidate for applications in redox-flow batteries. Recent results on both these fronts will be discussed.

Wiring redox non-innocent metallo-ligands to a main group atom: Applications in flow batteries and small molecule multi-electron transformations

252nd National Meeting (2016)

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