Tautomerism in some Schiff bases, fluorescence study

Fluorescence spectra of four Schiff bases of salicylidene aniline (SA) derivatives, and of five compounds fi om the naphthylidene aniline (NA) derivatives were run in hexane and methanal. The two series showed either no fluorescence emission or a weak one in hexane. The fluorescence spectra for SA and NA series suggest the presence of different mechanisms to accrue through the excited states. It was possible to synthesize a NA compound which exists completely in the Keto form and another compound in this series which. was unable to form a keto structure. Therefore it was possible to use those two compounds as models to assign the different mechanism of excitation in the two series.