Characterization of [C₆H₇N]⁺˙ radical cations by tandem mass spectrometry

Collisional Activation, charge‐stripping and neutralization/reionozation mass spectra allow the identification of six [C₆H₇N]⁺˙ isomers, namely the molecular ions of the three isomeric picolines, 1⁺˙–;3⁺˙, ionized 2‐ and 4‐methylene dihydropyridines, b—c, and ionized pyridinium methylide, a. The implication of the distonic forms a and b in some fragmentation reactions of funct of onalized (position 2) pyyridines is briefly discussed. Molecular orbital calculations indicate the b>a>1⁺˙ stability sequence.