Studies in mass spectrometry. IV—Fragmentation of aryltriflates. Substituent effects on [ArO]+ ion abundances: Looking for a best suited electron energy in the steady state approach. Experimental evidence for the ‘through bond’ stabilization of aryl cations by meta electron donor Substituents

The fragmentation patterns of 24 substituted phenyltrifluoromethanesulfonates has been determined by exact mass and metastable transition measurements. The influence of the ring substituent(s) on the abundance of the ArO]+ ions has been investigated at low energies and a new standard parameter for plotting against Hammett's ó constants is proposed. The direct loss of CF₃SO₃ from the molecular ion of 3,5-(diisopropyl)-phenyl-, 3,5-(dicyclopropyl)phenyl- and 3,5-di(α-methylcyclopropyl)-phenyl-methanesulfonate, and further observations on the fragmentation processes of these compounds are consistent with M.O. calculations on the ‘through bond’ stabilization of the Ar]+ σ state by meta electron donor substituents.