A Bioinspired Iron-Molybdenum μ-Nitrido Complex and Its Reactivity toward Ammonia Formation

Multimetallic nitride species, especially those containing biologically related iron or molybdenum, are fundamentally important to understand the nitrogen reduction process catalysed by FeMo-nitrogenase. However, until now, there remains no report about the construction of structurally well-defined FeMo heteronuclear nitrido complex and its reactivity toward ammonia formation. Herein, a novel thiolate-bridged Fe^II Mo^VI complex featuring a bent Fe-N≡Mo fragment is synthesized and structurally characterized, which can be easily protonated to form a μ-imido complex. Subsequently, through the proton-coupled electron transfer (PCET) process, this imido species can smoothly convert into the μ-amido complex, which can further undergo reductive protonation to afford the FeMo complex containing an ammine ligand. Overall, we present the first well-defined {Fe(μ-S)₂ Mo} platform that can give a panoramic picture for the late stage (N^3- →NH^2- →NH₂^- →NH₃ ) of biological nitrogen reduction by the heterometallic cooperativity.