Dansyl based selective fluorescence sensor for Hg in aqueous environment: an experimental and computational studies.

The selective fluorescence sensors are used for the analysis of toxic pollutants in the environment. In this study, phenol dansyl amide (PDA) was prepared as highly stable fluorescence ligand by using nucleophilic substitution reaction. Its interaction with eighteen different cations including Hg²⁺ and series of anions were investigated by using UV-visible and fluorescent spectrophotometry. However, PDA significantly indicated high sensitivity and selective quenching effect towards mercury ion. Furthermore, Density Functional Theory (DFT) along with the B3LYP method was implemented to explore minimum energy complex and fluorescence mechanism. The computed results revealed that among four possible optimized complexes of PDA and Hg⁺ ion, the first complex (PDA-Hg²⁺–I) was observed to be the most stable complex with the estimated energy difference of 8.91 kcal/mol and intermolecular charge transfer mechanism was observed in the same complex by HOMO and LUMO computation. [ABSTRACT FROM AUTHOR]