Reduction of Nitrogen Oxides by Dimagnesium(I) Compounds

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Inorganic Synthesis

Background:

• Low-valent magnesium compounds are reactive intermediates.
• Nitrous oxide (N2O) and nitroxyl radicals (NHC-NO•) are versatile reagents.
• Understanding the reactivity of low-valent magnesium is crucial for developing new synthetic methodologies.

Purpose of the Study:

• To explore the reactivity of dimagnesium(I) reagents with N2O and NHC-NO• radicals.
• To synthesize and characterize novel magnesium complexes containing oxide and nitroxyl moieties.
• To investigate the electronic structure and reaction mechanisms of these new complexes.

Main Methods:

• Synthesis of dimagnesium(I) reagents and their reactions with N2O and NHC-NO•.
• Isolation and characterization of products using X-ray crystallography and NMR spectroscopy.
• Computational studies (DFT) to elucidate electronic structures and reaction pathways.

Main Results:

• Formation of a tetra-magnesium oxide/hyponitrite complex [{(NCN^Dipp)Mg}(μ-N₂O₂){Mg(NCN^Dipp)}₂(μ-O){Mg(NCN^Dipp)}] (1) from dimagnesium(I) and N2O.
• Synthesis of NHC-nitroxyl complexes [(NCN^Dipp)Mg(κ²-N,O-ON-NHC^Dipp)] (2) and [(BDI^Dipp)Mg(κ²-N,O-ON-NHC^Mes)] (3) via reduction of NHC-NO• radicals by dimagnesium(I) reagents.
• Reaction of a magnesium(II) butyl complex with NHC^Dipp-NO• yielding [(BDI^Dipp)Mg(κ¹-O-ON-NHC^Dipp)(THF)] (4) and n-octane.

Conclusions:

• Dimagnesium(I) reagents exhibit rich reactivity towards N2O and nitroxyl radicals, enabling the formation of unique magnesium complexes.
• The study demonstrates novel synthetic routes to magnesium-containing oxide, hyponitrite, and nitroxyl species.
• Computational and experimental data provide insights into the electronic structure and reaction mechanisms involving low-valent magnesium.