Methyl Transfers. 10. The Marcus Equation Application to Soft Nucleophiles

Article abstract of DOI:10.1021/ja00309a040

The Marcus equation to methyl transfers is shown to cover reactions of " soft" nucleophiles, although small discrepancies occur.Rates and equilibria are reported for a series of reactions of arylmethylselenides with (p-chlorophenyl)dimethylselenonium ion.Experimental reaction rates between "hard" methylating agents and "soft" nucleophiles show small deviations from the calculated values, mostly but not always in the direction predicted by the HSAB principle.The Marcus equation fails to explain the previously reported "inversion" of reaction rates of 4-nitrothiophenoxide and of 4-nitrophenoxide with methyl iodide and dimethyl sulfate.Identity rates for dimethyl sulfate, methyl methanesulfonate (using 3He), methyl iodide (using 125I), and methyl triflate (using 35S) in sulfolane are reported.