A coumarin derivative-Cu2+ complex-based fluorescent chemosensor for detection of biothiols. Issue 60 (1st October 2020) - Hien, Nguyen Khoa
Abstract : This study opens a new research direction towards the utilization of complexes between metal ions and fluorescent ligands for the detection of biothiols based on the theoretical calculations of stability constants. Abstract : Herein, a novel fluorescent sensor has been developed for the detection of biothiols based on theoretical calculations of the stability constant of the complex between a Cu 2+ ion and ( E )-3-((2-(benzo[ d ]thiazol-2-yl)hydrazono)methyl)-7-(diethylamino) coumarin (BDC ) as a fluorescent ligand. In this study, on the basis of density functional theory method, the Gibbs free energy of ligand-exchange reaction and the solvation model were carried out using thermodynamic cycles. The obtained results are in good agreement with the experimental data. The BDC –Cu 2+ complex can be used as a fluorescent sensor for the detection of biothiols in the presence of non-thiol containing amino acids, with a detection limit for cysteine at 0.3 μM. Moreover, theoretical calculations of excited states were used to elucidate variations in the fluorescence properties. The computed results show that the excited doublet states D2 and D1 are dark doublet states, which quench the fluorescence of the complex.