A fluorescent sensor for Zn2+ and Cd2+ based on a diarylethene derivative with an indole-2-methylhydrazone moiety

A fluorescent sensor for Zn2+ and Cd2+ based on a diarylethene derivative with an indole-2-methylhydrazone moiety was constructed. The photochmmism and photoswitchable fluorescence can be reversibly modulated by UV/Vis light and M2+/EDTA (M = Zn2+ or Cd2+). Upon addition of Zn2+ or Cd2+, an obviously large red-shift emission peak by 105 nm, and fluorescence quantum yields enhanced by 72-fold and 48-fold, respectively, with a concomitant black-to-green fluorescence color change was observed. The 1:1 stoichiometry complexes with Zn2+ and Cd2+ were confirmed by both Job's plot and Benesi-Hildebrand expression. As a result, the binding constants between sensor and metal ions were calculated to be 8.88 x 10(4) L mol(-1) for Zn2+ and 4.36 x 10(4) L mol(-1) for Cd2+, respectively. And the detection limit of lo for Zn2+ and Cd2+ was 3.82 x 10(-7) mol L-1, and 5.74 x 10(-7) mol L-1, respectively. Moreover, the fluorescent can be used to detect Zn2+ and Cd2+ in tap water sample with a high accuracy.

Automated summary

The fluorescent sensor developed based on an indole-2-methylhydrazone moiety showed high sensitivity and accuracy in detecting Zn2+ and Cd2+, with detection limits of 3.82 x 10(-7) mol L-1 and 5.74 x 10(-7) mol L-1, respectively.