EFFECT OF ARYL LIGANDS ON THE CHEMICAL HARDNESS OF ARYLMERCURY CATIONS

F-19 NMR spectroscopy was used to study the exchange reactions involvi ng 4-fluorothiophenoxides, 4-nitrophenoxides, chlorides, and acetates of arylmercury and triphenylphosphinegold. The analysis of the data on equilibrium constants allows one to obtain information on the compara tive chemical hardness of ArHg+ and Ph(3)PAu(+) cations. The increase in the electron-donating ability of aryl ligands enhances the chemical hardness of ArHg+ cations, their influence being best described by si gma(0) constants of substituted phenyl groups.