Rapid synthesis of a BODIPY derivative serving as a highly selective and sensitive fluorescence chemosensor for Hg2+ ion detection

Abstract

We synthesized 2-amino-1,3-propanediol-modified boron dipyrromethene (BODIPY) in a rapid two-step synthesis, with a total reaction time of 6 hours. The resulting fluorophore's emission was significantly quenched by polar solvents but increased fourfold upon the addition of Hg²⁺ ions. Notably, this BODIPY fluorophore exhibited high selectivity toward Hg²⁺ ions over various other metal ions (Li⁺, Na⁺, K⁺, Ca²⁺ Co²⁺, Cu²⁺, Ni²⁺, Pb²⁺, Zn²⁺, Mn³⁺, Ag⁺, and Fe³⁺), with a binding constant of 7.36 × 10⁴ M⁻¹. The binding mechanism was investigated using proton nuclear magnetic resonance (¹H NMR) and infrared (IR) spectroscopy and revealed that 2-amino-1,3-propanediol moieties chelated the Hg²⁺ ions. These chelated Hg²⁺ ions could be displaced by hexadentate EDTA molecules. Furthermore, treating BODIPY with an acid restored fluorescence emission, while a base diminished it, and this process was reversible. This rapidly synthesized BODIPY fluorophore holds great potential for Hg²⁺ ion detection.