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 FeII MoVI 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 (N3- →NH2- →NH2- →NH3 ) of biological nitrogen reduction by the heterometallic cooperativity.
Keywords: FeMo Nitrides; Heterometallic Complexes; Nitrogen Fixation; N−H Bond Formation; Proton-Coupled Electron Transfer.
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