Ruggi and Tortajada Research Groups recently published a new article together in the Journal of American Chemical Society, JACS, titled; “Green Ammonia Generation with a Polypyridine Cobalt Complex and Visible Light“. 

Congratulations to Dr. Albert Ruggi and Dr. Andreu Tortajada Navarro and to both groups on this exciting collaboration and contribution to sustainable chemistry!

To read the article: https://pubs.acs.org/jacsat/article/148/30/31621/5234335/Green-Ammonia-Generation-with-a-Polypyridine

Abstract

The use of a first-row transition metal complex and visible light was exploited to promote the photosynthesis of ammonia from nitrite ions. This is achieved in neutral aqueous solution by employing a cobalt polypyridine complex (CoL) within a light-driven catalytic scheme involving [Ru(bpy)₃]²⁺ (where bpy = 2,2′-bipyridine) as the sensitizer and ascorbate as the electron donor. Under visible light irradiation, the resulting photosystem produces NH₃ with a quantum yield up to 3% and a selectivity approaching 100%, achieving a maximum turnover number (TON) up to 2150. Transient absorption spectroscopy and density functional theory provided a robust mechanistic picture, showing that binding of the NO₂^– substrate occurs at the one-electron reduced metal complex, while also ascertaining the energetic feasibility of subsequent elementary reaction steps. All in all, this work uncovers the great potential of first-row transition metal polypyridine complexes toward the synthesis of chemicals of industrial relevance.