Eu3+-β-diketone functionalized covalent organic framework hybrid material as a sensitive and rapid response fluorescent sensor for glutaraldehyde.

A covalent organic framework (named as TpDq) linked by β-ketoamine was prepared by imine condensation reaction with 1,3,5-triformylphloroglucinol (TFP) and 2,6-diaminoanthraquinone (DAAQ) as building blocks. Via employing a functionalized modification strategy, a new lanthanide complex Eu3+-β-diketone functionalized covalent organic framework hybrid material, Eu-TTA@TpDq (TTA = 2-thenoyltrifluoroacetone), has been synthesized. After post-synthetic modification (PSM), the shape and structure of the parent framework is well preserved and the modified material shows remarkable luminescence properties. Based on this, we designed it as a fluorescent probe and tried to use it to sense common aldehydes. The results indicate that Eu-TTA@TpDq exhibits a turn-off response toward glutaraldehyde which can distinguish from other common aldehydes. The fluorescent probe has the advantages of reusability, pH stability (4.50-8.52), fast luminescence response (<1 min) and low detection limit. The linear range of this method was 0-100 μM; the detection limit was 4.55 μM; the relative standard deviation was 2.16%. Furthermore, it has broad application prospect in both practical sensing of glutaraldehyde in water environment and simple detection of glutaraldehyde vapor. In addition, we preliminarily discussed the possible sensing mechanism.