Infrared and Proton Magnetic Resonance Spectra of N-Alkyl and N-Aryl Salicylaldimines

Abstract

The infrared spectra of nine N-alkyl and twentyfour N-aryl salicylaldimines have been determined. ¹⁵N-Labelling of N-p-tolylsalicylaldimine yields assignments of the more significant vibrational bands and enables an assessment of the extent of vibrational coupling of ν C=N. The proton magnetic resonance spectra of the salicylaldimines show that they exist in the phenolimine form at room temperature in deuterochloroform. Electron withdrawing substituents reduce the magnetic shielding of the hydroxyl proton by modifying the capacity of the nitrogen atom for entering into hydrogen bonding.