53565-66-5Relevant academic research and scientific papers
A study of the tautomers of N-salicylidene-p-X-aniline compounds in methanol
Vargas,Amigo
, p. 1124 - 1129 (2007/10/03)
We have studied the enol-imine→keto-amine tautomeric equilibrium of N-salicylidene-p-X-aniline compounds with X = Me, OMe, NMe2 as electron donor substituents and X = COMe, CN and NO2 as electron acceptor substituents. The equilibrium constants (Ktauo) and standard thermodynamic properties ΔGtauo, ΔHtauo and ΔStauo were measured and calculated in methanol solution at various temperatures, by means of excitation fluorescence spectroscopy. We have analyzed the p-phenylaniline substitution effect on Ktauo and the thermodynamic properties through the Hammett parameters σ. We have performed molecular orbital calculations at the semiempirical AM1 and ab initio HF/3-21G levels to interpret the experimental results, explicitly including the solute-solvent interaction through the formation of an intermolecular hydrogen bond between the salicylidene and methanol molecules. These computational results show a good correlation with the experimental values. An interpretation of the experimental values of TΔSo, based on changes in the molecular structure produced in the enol-imine→keto-amine tautomeric reaction, is proposed.
