Fluorescent salicylaldehyde hydrazone as selective chemosensor for Zn2+ in aqueous ethanol: a ratiometric approach.

4-N,N-diethylaminosalicylaldehyde hydrazone Schiff base (1) and its analogues (2-6) were synthesized and characterized by NMR, MS and elemental analysis. Compound 1 exhibited ratiometric fluorescent response to Zn(2+) over other metal ions in aqueous ethanol solution with neutral buffer. The complexation ratio, site and constant and the effect of pH value and water fraction on its fluorescent response to Zn(2+) were investigated.