Infrared Study of the Hydrogen Bond Complexes Between N-Methylsuccinimide and Phenols

Abstract

The hydrogen bonded complexes between N-methylsuccinimide and phenols (pKa = 10.2 → 6) are investigated by infrared spectrometry. The thermodynamic parameters for the 1–1 complexes are determined in carbon tetrachloride-. The formation constants at 298 K range from 15 to 150 dm³ mol⁻¹, the enthalpies of complex formation from - 20 to - 30 kJ mol⁻¹, the changes of entropy from - 22 to - 40 J K⁻¹ mol⁻¹ and the frequency shifts of the v(OH) stretching vibration from 170 to 340 cm⁻¹. The complexes are weaker than those involving the monocarbonyl bases. The decrease of the force constant of the bonded carbonyl group ranges from 0.48 to 0.65 N cm⁻¹. The force constant of the free C=O group slightly increases upon complex formation, in agreement with the cooperatively theory.

Key Words:

• N-methylsuccinimide
• basicity
• infrared spectra