Green synthesis and recognition of Cr₂O₇2− and CrO₄2− ions of a novel Schiff base fluorescent probe

This work primarily investigates the green synthesis of 1-ferrocenyl-2-thiazolyl Schiff base (probe L) and its anion recognition performance. Using acetylferrocene as the starting material and p-toluenesulfonic acid as the catalyst, 1-ferrocenyl-2-thiazolyl Schiff base was synthesized and characterized via a solvent-free grinding method. Optimal synthesis conditions were obtained through the optimization of the synthetic method. The anion recognition performance of probe L was explored, and UV–Vis spectroscopy revealed that probe L could specifically recognize Cr 2 O 7 2− and CrO 4 2− ions with strong anti-interference ability. The effects of time and pH on its recognition performance were further investigated. Quantitative analysis showed that the binding ratios of probe L to Cr 2 O 7 2− and CrO 4 2− were both 1: 1, with binding constants of 6.8182 × 10 5 M −1 and 5.7806 × 10 5 M −1 , respectively; the detection limits reached 1.6993 × 10 −5 M and 1.6800 × 10 −5 M. The complexation mechanism of probe L with Cr 2 O 7 2− and CrO 4 2− was further illustrated by IR and 1 H NMR titrations. In practical applications, probe L can be used to roughly detect Cr 2 O 7 2− and CrO 4 2− in water samples via test strips, offering a rapid and simple detection method.