A new Schiff base fluorescent-colorimetric probe containing fluorene-naphthalene structure: Multifunction detection

A new fluorescent-colorimetric probe 1-[(9H-fluoren-2-ylimino)methyl]-2-naphthalenol (FIMN) was designed and synthesized. FIMN is a multi-ion probe which can detect not only Al3+ ions by the change of fluorescent intensity, but also Fe3+, Co2+, and Cu2+ ions by color changes. The detection limits of FIMN with Al3+, Fe3+, Co2+ and Cu2+ ions were 2.643x10(-8), 1.843x10(-6), 8.349x10(-5) and 5.035x10(-5) M. The bonding ratios and association constant (Ka) of FIMN with Al3+, Fe3+, Co2+ and Cu2+ ions were studied by Job's plot and concentration titration experiments. H-1 NMR titration experiments were conducted to discuss the coordination modes of FIMN. And the detection mechanism can be explained by C=N isomerization.