A chalcone-based fluorescent chemosensor for detecting Mg²⁺ and Cd²⁺

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.