Electrochemical synthesis of Betti bases and their application as fluorescent probes for Hg2+ ions

The present study included the first electrochemical synthesis of Betti bases in deep eutectic solvents as a green and sustainable method of synthesis. The reaction conditions were optimized by varying different factors like time and type of electrode material. The prepared compounds were utilized as fluorescent probe for mercury ions. The fluorescence intensity of the synthesized Betti base derivatives 4a-e was investigated and the highest fluorescence intensity was displayed by compound 4e (the 2-fluorophenyl derivative). The Betti base 4e showed excitation/emission peaks at 368/461 nm, respectively. The Betti based fluorescence was quenched by Hg²⁺ ions. The fluorescent probe responded linearly to Hg²⁺ concentration in the range of 0.2 to 10.0 µM. The limit of detection (LOD) was estimated to be 0.041 µM. The Stern-Volmer constant (K_sv) was calculated to be 2.69 ± 0.07 × 10⁵ M^-1.