Ammonia Synthesis from a Pincer Ruthenium Nitride via Metal-Ligand Cooperative Proton-Coupled Electron Transfer

作者：Lindley Brian M; Bruch Quinton J; White Peter S; Hasanayn Faraj; Miller Alexander J M

来源：Journal of the American Chemical Society, 2017, 139(15): 5305-5308.

DOI：10.1021/jacs.7b01323

The conversion of metal nitride complexes to ammonia may be essential to dinitrogen fixation. We report a new reduction pathway that utilizes ligating acids and metal ligand cooperation to effect this conversion without external reductants. Weak acids such as 4methoxybenzoic acid and 2-pyridone react with nitride complex [(H-PNP)RuN](+) (H-PNP = HN-((CH2CH2PBu2)-Bu-t)(2)) to generate octahedral ammine complexes that are kappa(2)-chelated by the conjugate base. Experimental and computational mechanistic studies reveal the important role of Lewis basic sites proximal to the acidic proton in facilitating protonation of the nitride. The subsequent reduction to ammonia is enabled by intramolecular 2H(+)/2e(-) proton-coupled electron transfer from the saturated pincer ligand backbone.

• 出版日期2017-4-19