a Institute of Organic Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44, Warsaw 01-224, Poland
b Institute of Chemistry, Technical University of Szczecin, Al. Piastów 42, Szczecin 71-065, Poland
Abstract:
A series of 11 Schiff's bases derived from substituted salicylaldehyde and aliphatic amines has been studied in the solid state by 15N and 13C cross-polarization magic angle spinning (CPMAS) nuclear magnetic resonance (NMR). 15N CPMAS is especially useful for investigation of the tautomerism in the compounds considered, owing to the large difference in the nitrogen chemical shifts of OH and NH tautomers. In the solid state, three of the compounds examined were shown by 15N NMR to exist as OH tautomeric forms, and the remaining eight as the corresponding NH forms. This was confirmed by 13C CPMAS. The results reported were compared with those obtained in CDCl3 solutions.