Synthesis of substituted aromatic aldehydes bis-Schiff bases and their spectrum properties

A series of Schiff bases were synthesized by reacting aromatic aldehyde with primary amines in an ice bath. Four of them were first reported. The chemical structures of these compounds were characterized by means of IR and H-1 NMR spectra. Their UV absorption and fluorescence spectrum were determined in solution and solid state, and the relationship between the molecule structures and the spectra was discussed. It was found that an OH group at an ortho position in the salicylaldehyde is necessary for strong fluorescence properties of Schiff base and the main factor of molecular tautomerization leading to different performance on absorption and fluorescence spectrum.