Catalyst‐Free Selective Reduction of Nitrogen Dioxide to Nitric Oxide

ABSTRACT Nitrogen dioxide (NO 2 ) is a highly toxic gas and a notorious respiratory irritant that contributes to the greenhouse effect and acid rain. Herein, we study the catalyst‐free reduction of NO 2 with boranes, silanes, and the hydrogen surrogates 1,4‐cyclohexadiene and isopropyl alcohol, resulting in the selective formation of nitric oxide (NO). Selective NO generation was confirmed by electron paramagnetic resonance spectroscopy and low‐temperature 15 N{ 1 H} nuclear magnetic resonance spectroscopy. Additionally, density functional theory calculations have been employed to probe the mechanism of these reductions.