Bioinspired copper-catalysed nitrous oxide reduction with simultaneous N–H or O–H bond oxidation

Abstract

Herein, we report on a bioinspired reduction of nitrous oxide in the presence of hydrogen-donating molecules, which are simultaneously oxidised. The copper-/TEMPO-based molecular catalyst has been previously reported to oxidise, for example, alcohols to aldehydes, diols to lactones, amines to imines, and, more recently, for the N-formylation of amines with methanol using (aerial) oxygen as a terminal oxidant. In this report, we demonstrate that it is possible to decompose nitrous oxide, a natural greenhouse gas and industrial waste gas, at low temperatures. This process simultaneously enables the oxidation of amines to imines and the formation of aminoacetal/aminal through the addition and oxidation of methanol. In this context, the Cu/TEMPO catalyst mimics nitrous oxide reductase (N2OR) and alcohol oxidase (AO) simultaneously. The catalyst is formed in situ from inexpensive and commercially available precursors. Selectivities and yields can be controlled by varying the composition of the substrate mixture and oxidant. This approach is attractive for the synthetic valorisation of organic molecules and utilisation of nitrous oxide, which remains a critical greenhouse gas and a byproduct of large-scale industrial processes, such as fertilizer production. These reactions, facilitated by a robust and affordable catalyst, are easy to carry out, making them highly practical for industrial applications.