Theoretical Studies on the Mechanism of Pyridinolysis of Y-Substituted Phenoxy Carbonyl Isothiocyanate

초록

The kinetics and mechanism of the pyridinolysis (XC5H4N) of phenoxy carbonyl isothiocyanate in gas phase are investigated at room temperature 25.0℃. The Hammett and Br?nsted plots for substituent X variations in the nucleophiles exhibit expected slopes with excellent correlations. These are interpreted to indicate a mechanistic behavior for the reactions whether these are following concerted or a stepwise route during expulsion of the isothiocyanate (NCS) leaving group from the intermediate or TS. The positive and negative βX values imply the characteristics of the nucleophilic attack. In addition the steric effects of the ligands play an important role in determining the pyridinolysis rates of isothiocyano phosphates.