Isocyanide Ligation Enables Electrochemical Ammonia Formation in a Synthetic Cycle for N Fixation.

Transition-metal-mediated splitting of N to form metal nitride complexes could constitute a key step in electrocatalytic nitrogen fixation, if these nitrides can be electrochemically reduced to ammonia under mild conditions. The envisioned nitrogen fixation cycle involves several steps: N binding to form a dinuclear end-on bridging complex with appropriate electronic structure to cleave the N bridge followed by proton/electron transfer to release ammonia and bind another molecule of N. The nitride reduction and N splitting steps in this cycle have differing electronic demands that a catalyst must satisfy.