Nucleophilic reactivity and solvation of succinimide and phthalimide anions in acetonitrile–methanol mixtures

Abstract

Nucleophilic reactivity and solvation patterns for succinimidide and phthalimidide ions have been characterized through three procedures, kinetic and enthalpy of solution measurements in aceto-nitrile-methanol mixtures, and enthalpy of reaction measurements in acetonitrile. Quantitative analysis indicates that activation enthalpy vs. activation entropy correlation is more sensitive and versatile than activation enthalpy vs. reaction ethalpy correlation as the method for detecting the effects of various molecular interactions on rates of reaction. Any essential difference in nucleophilic reactivities and in solvation patterns was not observed between imidide and carboxylate ions, but a significant difference is found on the pK_a values in the aqueous phase and on the enthalpy of reaction with ethyl iodide in acetonitrile.