Chloride ion affinities of substituted benzylcations in the gasphase have been determined by means of an ICR mass spectrometer. The substituent effect has been analyzed in terms of the LArSR Eq., giving a ρ=13.6 and an r+=1.31.
Gas-Phase Substituent Effects in Highly Electron-Deficient Systems. II. Stabilities of 1-Aryl-2,2,2-trifluoroethyl Cations Based on Chloride-Transfer Equilibria
of −10.6, supporting our previous conclusion that the highly electron-deficient benzylic carbocation systems are characterized by extremely high resonance demands. This r+ value, furthermore, conformed a linear relationship between the r+ value and the relative stability of the unsubstituted member of the respective benzylic carbocations, clearly demonstrating a continuous spectrum of varying resonance