Studies in organic mass spectrometry. XXII –Evidence for the existence of cyclic oxonium ions in the gas phase

The electron impact induced loss of a phenoxy radical from the molecular ions of α,ω‐bis‐aryloxy alkanes ΦO(CH 2 ) n OΦ ( 1 n ; n = 2–7) and F‐ p ‐C 6 H 4 (CH 2 ) n OΦ(2 n ; n = 2−5) is the result of functional group interaction. Labelling data provide conclusive evidence for the O‐aryl tetra‐hydrofuranium and O‐aryl tetrahydropyranium structures of the resulting decomposing species (lifetimes between 10 −6 and 10 −5 s) in the case of n = 4 and 5, respectively. Evidence is presented for the occurrence of phenyl participation in the loss of ΦOH from the molecular ions of the lower homologues of 1 n and 2 n ( n = 2, 3).