Ortho effects in organic molecules on electron impact: 19—Competing oxygen transfers from nitro group to sulphur and acetylinic carbons in 2†nitrophenylphenylethynylsulphides

Oxygen transfers to both the acetylenic carbons and sulphur are noticed in parallel fragmentation pathways during the electron‐impact induced decompositions of 2‐nitrophenylphenylethynylsulphides. Single oxygen transfer to acetylinic carbons leads to the most abundant ion corresponding to the benzoyl cation whilst double oxygen transfers to both the acetylenic carbons followed by the ejection of two CO units from the M+˙ ion afford another abundant fragment corresponding to the phenothiazine radical cation. However, the oxygen transfers to sulphur yield a less abundant [M  SO2H]+ ion. The proposed fragmentation pathways and the ion structures are sup ported by high‐resolution data, collision‐induced dissociation Linked‐scan spectra and chemical substitution. Copyright © 1989 John Wiley & Sons, Ltd.