Electrocatalytic Reduction of Nitrogen to Hydrazine Using a Trinuclear Nickel Complex

Activation and reduction of N2 have been a major challenge to chemists and the focus since now has mostly been on the synthesis of NH3. Alternatively, reduction of N2 to hydrazine is desirable because hydrazine is an excellent energy vector that can release the stored energy very conveniently without the need for catalysts. To date, only one molecular catalyst has been reported to be able to reduce N2 to hydrazine chemically. A trinuclear T-shaped nickel thiolate molecular complex has been designed to activate dinitrogen. The electrochemically generated all Ni(I) state of this molecule can reduce N2 in the presence of PhOH as a proton donor. Hydrazine is detected as the only nitrogen-containing product of the reaction, along with gaseous H2. The complex reported here is selective for the 4e–/4H+ reduction of nitrogen to hydrazine with a minor overpotential of ∼300 mV.