Classification, Synthesis, Isomerism, and Spectral Characterization of Schiff Bases

Schiff bases have been known for 160 years and there is a multitude of information about them. This review focuses on their classification. The examples were classified based on the number of azomethine groups (mono-, bis-, tris-, tetrakis-, oligo-, and polymer Schiff bases) and the nature of their chain (cyclic and acyclic Schiff bases). Many imines are synthesized by condensing carbonyl compounds with amines and the mechanism of this reaction has been described. The main types of isomerism found at Schiff bases are geometric isomerism, atropizomerism, and imine-enamine tautomerism. After obtaining them they can be spectrally characterized using FTIR, UV-Vis, 1H NMR, 13C NMR, and mass spectrum and they were presented.