Preparation and Reactivity of Anionic Iron Sandwich Complex Bearing π‐Phenol Ligand Acting as Proton‐Coupled Electron Transfer Reagent

A neutral Fe(II) sandwich complex bearing a π‐phenol ligand with a trifluoroborate substituent [Cp*Fe(η 6 ‐2‐ t Bu‐6‐BF 3 ‐C 6 H 3 OH)] is designed and prepared, which affords the corresponding anionic Fe(I) sandwich complex [Cp*Fe(η 6 ‐2‐ t Bu‐6‐BF 3 ‐C 6 H 3 OH)] − with an effective O−H bond dissociation free energy at 40.7 kcal/mol in tetrahydrofuran on treatment with KC 8 . The anionic complex acts as a proton‐coupled electron transfer reagent for the reduction of organic substrates such as acetophenone and anthracene, whereas the reaction with a Mo(IV) nitride complex leads to the stoichiometric formation of ammonia.