Nitrogen oxides (NOx) released from human activities cause serious environmental issues and affect the global nitrogen cycle. Thus, conversion of nitrogen oxide (NOx) is one of the most important catalysis technologies due to its global environmental impact. 

Biological NOx transformation is known to a denitrification process, which occurs via a sequential deoxygenation pathway (NO3– → NO2 → NO → N2O → N2). By applying a biological methodology, the researchers have devised a synthetic approach to this issue by utilizing a bifunctional metal catalyst for producing value-added products from NOx. 

The catalysis for the production of oximes from benzyl halides with sodium nitrite was successfully demonstrated with TON >200 under mild conditions. Various substrates were employed to expand the substrate scope. Kinetic studies and theoretical evaluations suggest that a direct NO transfer to the alkyl halide to produce oxime as an important step for this catalysis. Therefore, a nickel(I)–•NO species is postulated to be the key species effectively activating organic halides to generate a new N–C bond. This is an unprecedented nickel-mediated catalytic transfer of a NO group to alkyl halides, where the source of NO is NOx.

Dr. Lee said “Our study presents a novel way to utilize NOx to produce useful value-added organic products, with the first success in nickel mediated catalysis. Our nickel catalyst effectively fulfills a dual purpose, namely, deoxygenating NOx anions and catalyzing C–N coupling.” 

Dr. Yunho Lee also emphasized his work as follows; “By employing an earth-abundant cheap transition metal, we have succeeded in generating a Ni–NO species from an NOx anion and then utilize it in further conversion into value-added products, which is a unique and economically viable strategy. A novel NOx conversion and utilization (NCU) technology based on a nickel organometallic reaction platform is a step forward in achieving sustainable N-neutral chemical industry.”

[Reference]

Sudakar Padmanaban, Jonghoon Choi, Hugo Vazquez-Lima, Donghwi Ko, Dagyum Yoo, Jinseong Gwak, Kyung-Bin Cho*, and Yunho Lee* Nickel-Catalyzed NO Group Transfer Coupled with NOx Conversion, Journal of the American Chemical Society, https://doi.org/10.1021/jacs.1c13560

[Main Author] Yunho Lee (Seoul National University), Sudakar Padmanaban (Seoul National University)

* Contact : yunhochem@snu.ac.kr