UV-Visible Absorption Spectroscopic Studies of Intramolecular Proton Transfer in N-(R-Salicylidene)-alkylamines

Results of UV-visible spectroscopic studies on thermodynamic parameters of the intramolecular proton transfer equilibrium in N-(R-salicylidene)-alkylamines in solution are presented. The estimated DeltaHPT values in CH2Cl2 solution are within the range –5.2 to –13.9 kJ/mol. DeltaSPT values are negative: from –28 to –48 J/molK. The obtained results demonstrate the influence of the acidity of the phenolic group as well as charge delocalization on the position of the proton transfer equilibrium.