A dual functional fluorescent sensor for the detection of Al and Zn in different solvents

( E )- N ′-((2-Hydroxynaphthalen-1-yl)methylene)imidazo[2,1- b ]thiazole-6-carbohydrazide ( X ), a new fluorescent sensor, was designed and synthesized based on imidazo[2,1- b ]thiazole and 2-hydroxy-1-naphthaldehyde, which could be used to detect Al 3+ in methanol buffer solution and detect Zn 2+ in ethanol buffer solution with detection limits of 1.45 × 10 −7 M and 1.29 × 10 −8 M, respectively. X showed high sensitivity and selectivity towards Al 3+ and Zn 2+ in the presence of other metal ions. The fluorescence intensity of X was reversible even after six cycles with the sequentially alternative addition of metal ions (Al 3+ and Zn 2+ ) and PPi, showing an efficient "off-on-off" fluorescence behavior. The complexation ratio of X to Al 3+ and Zn 2+ was 1 : 1, which was proved by mass spectrometry and the B-H equation. The binding mode and sensing mechanism of X with metal ions (Al 3+ and Zn 2+ ) were verified by DFT/TDDFT calculations using Gaussian 09 based on the B3LYP/6-31G(d) basis set. A new fluorescent sensor, X , was designed and synthesized based on imidazo[2,1- b ]thiazole and 2-hydroxy-1-naphthaldehyde, which could be used to detect Al 3+ in methanol buffer solution and detect Zn 2+ in ethanol buffer solution, respectively.