Bernhard Hansert

[28] Synthesis of pure tetramethylammonium peroxynitrite

Publisher Summary This chapter discusses the synthesis of pure tetramethylammonium peroxynitrite. The synthesis is based on a biomimetic strategy in which tetramethylammonium superoxide is reacted directly with nitric oxide. The use of ammonia as the solvent and tetramethylammonium superoxide as the superoxide source is critical in this synthesis. The synthesis of tetramethylammonium peroxynitrite, [N(CH 3 ) 4 ][ONOO], as a pure, stable, bright yellow salt. Other preparations of peroxynitrite include (1) hydrogen peroxide and nitrite ester in base, (2) the solid-state preparation by ultraviolet (UV) photolysis of potassium nitrate to give 30μmol of ONOOK per gram as a solid mixture of peroxynitrite and nitrate, and (3) the reaction of sodium azide and ozone. The reaction between tetramethylammonium hydroxide pentahydrate and potassium superoxide is a solid-phase reaction that is performed under vacuum and that requires efficient mixing and relatively long reaction times. When prepared under dry and maintained nitrogen, tetramethylammonium peroxynitrite is stored for several months with little detectable decomposition.

O-atom Transfer versus Aromatic Nitration Reactions of Peroxynitrite

The O-atom transfer reactions of the cytotoxin peroxynitrite, ONOO− has been examined using thianthrene-5-oxide as a probe at various pH. Under basic conditions the product is a sulfide/sulfone derivative indicating strong nucleophilic oxidant character of peroxynitrite. Under acidic conditions the predominant product corresponds to ring nitration of the thianthrene.

Electronic origin of variable denitrosylation kinetics fromisostructural {FeNO}7 complexes: X-ray crystalstructure of [Fe(oetap)(NO)]

In contrast to the nitrosyl derivative of iron(II) noctaethylporphyrin [Fe(oep)(NO)], the isostructural noctaethyltetraazaporphyrin complex [Fe(oetap)(NO)] exhibits fast nligand-promoted nitric oxide dissociation in the presence of pyridine and nN-methylimidazole.