Triggering Redox Activity in a Thiophene Compound: Radical Stabilization and Coordination Chemistry

The synthesis, metalation, and redox properties of an acyclic bis(iminothienyl)methene L^- are presented. This π-conjugated anion displayed pronounced redox activity, undergoing facile one-electron oxidation to the acyclic, metal-free, neutral radical L^. on reaction with FeBr₂ . In contrast, the reaction of L^- with CuI formed the unique, neutral Cu₂ I₂ (L^. ) complex of a ligand-centered radical, whereas reaction with the stronger oxidant AgBF₄ formed the metal-free radical dication L^.2+ .