CONSIDERED ONIUM IONS .40. PROTONITRONIUM DICATION (NO2H2+)

Protonitronium dication (1, NO2H2+), the assumed superelectrophile responsible for the nitration of deactivated aromatics as well as alkanes with nitronium salts in superacidic media, was found to be a minimum at both HF/6-31G* and MP2/6-31G** levels of ab initio calculations. IGLO N-15 NMR chemical shift as well as infrared frequencies were also calculated for 1. Attempts to experimentally observe 1 under superacidic conditions by N-15 NMR and FT-IR (Raman) spectroscopy were so far unsuccessful, due to the expected low equilibrium concentration of 1 in the studied systems.