Boeon Suh

A practical hydrazine-carbothioamide-based fluorescent chemosensor TCC (N-(4-chlorophenyl)-2-(thiophene-2-carbonyl)hydrazine-1-carbothioamide) was applied for Zn²⁺ detection. TCC exhibited selective fluorescence emission for Zn²⁺ and did not show any interference with other metal ions. In particular, TCC was utilized for the detection of Zn²⁺ in paper strips, zebrafish and real water samples. TCC could detect Zn²⁺ down to 0.39 μM in the solution phase and 51.13 μM in zebrafish. The association ratio between TCC and Zn²⁺ was determined to be 2:1 by ESI-mass and Job plot. The sensing mechanism of TCC for Zn²⁺ was illustrated to be a chelation-enhanced fluorescence process through spectroscopic experiments and theoretical calculations.

SBOD (sodium (E)‐2‐(3‐[5‐bromothiophen‐2‐yl]‐3‐oxoprop‐1‐en‐1‐yl)‐4,6‐dichlorophenolate) was designed and synthesized as a chalcone‐based fluorescent turn‐on chemosensor for Mg²⁺ and Cd²⁺. SBOD selectively detected Mg²⁺ and Cd²⁺ through the increase in effective fluorescence. Detection limits of SBOD for Mg²⁺ and Cd²⁺ were calculated to be 3.8 μM and 2.9 μM, respectively. The binding modes of SBOD for Mg²⁺ and Cd²⁺ were determined to be 1:1 by ESI‐MS and Job plot. Association mechanisms for SBOD to Mg²⁺ and Cd²⁺ were illustrated by ESI‐MS, UV–vis, fluorescence spectroscopy, and calculations.