Conversion of Dinitrogen and Oxygen to Nitric Oxide Mediated by Triatomic Yttrium Cations: Reversible N-N Bond Switching.

The direct coupling of dinitrogen (N ₂ ) and oxygen (O ₂ ) to produce value-added chemicals such as nitric acid (HNO ₃ ) at room temperature is fascinating but quite challenging because of the inertness of N ₂ molecules. Herein, an interesting reaction pathway is proposed for a direct conversion of N ₂ and O ₂ mediated by all-metal Y ₃ ⁺ cations. This reaction pattern begins with the N≡N triple bond cleavage by Y ₃ ⁺ to generate a dinitride cation Y ₂ N ₂ ⁺ , and the electrons that lead to N ₂ activation in this process mainly originate from Y atoms. In the following consecutive reactions with two O ₂ molecules, the electrons stored in the N atoms are gradually released to reduce O ₂ through re-formation and re-fracture of the N-N bonds, with concomitant release of two NO molecules. Therefore, the reversible N-N bond switching acts as an efficient electron reservoir to drive the oxidation of the reduced N atoms, leading to the formation of NO molecules. This method of producing NO by direct coupling N ₂ and O ₂ molecules, which is the reversible N-N bond switching, may provide a new strategy for the direct synthesis of HNO ₃ , etc.