Recognition of Al3+ and Zn2+ using a single Schiff-base in aqueous media

• We have designed a single fluorescent chemosensor for recognition of Al3+/Zn2+ base on ESIPT.
• 2-Methyl quinoline-4-carboxylic hydrazide was rarely synthesized.
• HL shows a large fluorescence enhancement (120/150-fold) in the presence of Al3+ and Zn2+, respectively.
• The detection limits for Al3+/Zn2+ reach at 10−7 M level.

A naphthalene derivative 2-hydroxy-α-naphthaldehyde-(2′-methylquinoline-4′-formyl) hydrazone (HL) as a fluorescent chemosensor for Al3+/Zn2+ in ethanol and water (9:1, v/v) has been designed and synthesized. The receptor shows a large fluorescence enhancement at 509 nm and 543 nm in the present of Al3+ and Zn2+, respectively. The excited-state intramolecular proton transfer (ESIPT) process, coupled with photoinduced electron transfer (PET) process are proposed to explain the observed spectral response.

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