Synthesis of Cd‐MOF and Eu³⁺@Cd‐MOF as Multitarget Sensors for Simultaneous Sensing Cr (VI) Anion and 4‐NA

ABSTRACT Metal–organic frameworks (MOFs) as a kind of sensing material plays an important role for environmental monitoring and human health. In this paper, we prepared a luminescent Cd‐MOF: [Cd 2 L·4H 2 O]·H 2 O. (H 4 L = 2,5‐bis‐(3,4‐dicarboxy‐phenyl)thiophene‐amide) under the solvothermal condition. Single crystal X‐ray diffraction analysis shows that Cd‐MOF has a 2D layer structure, and it exhibits a strong fluorescence emission at 470 nm. The sensing experiment displays Cd‐MOF as multitarget probe can selectively detect Cr (VI) anions and 4‐nitroaniline (4‐NA) with high sensitivity, good anti‐interference ability, and good recyclability. In addition, dual‐emission Eu 3+ @Cd‐MOF was obtained by encapsulating Eu 3+ ions into Cd‐MOF, in which Cd‐MOF sensitizes Eu 3+ ion emission. Accordingly, Eu 3+ @Cd‐MOF also acts as multitarget and self‐calibrated probe to selectively detect Cr (VI) ions and 4‐NA synchronously at the same conditions. However, the changes of fluorescence emissions of Eu 3+ @Cd‐MOF toward Cr (VI) ions are different from that of the original Cd‐MOF. The possible sensing mechanism be attributed to the competitive energy absorption between Cd‐MOF or Eu 3+ @Cd‐MOF and the analytes. All the results may provide broad prospects for developing multitarget sensing platform for sensing environment pollutants.