Iso-nitrous acid radical cation in the gas phase: first experimental evidence

The iso-nitrous acid radical-cation, HNO2+, was prepared for the first time by exothermic protonation of NO2 with H3+ and characterized by collisionally activated dissociation mass spectra. RRKM calculations that were based on B3LYP/6-311++G(3df,2pd) calculated energies and frequencies were consistent with experimental data that showed the loss of H and HO radicals to be the only two competitive fragmentation channels of HNO2+.