ИСТИНА

The resulting compound exhibits low-intensity fluorescence due to the process of electron transfer from the N-aryl group to the naphthalimide residue in the photoexcited state, which is confirmed by the data of quantum-chemical calculations by the PM6 method. The binding of Hg2+ in an aqueous acetate buffer solution at pH 6.0 is accompanied by the formation of a 1: 1 metal - ligand complex, in which electron transfer is suppressed, that leads to the fluorescence enhancement. The observed spectral changes were used to determine the value of the stability constant of the complex K (log K = 6.51 ± 0.03). The found detection limit of Hg2+ using the obtained sensor (28 nmol / L) has been found to be quite close the MPC for mercury in drinking water. The study of the selectivity of complexation showed that the presence of cations Cu2+, Zn2+, Ni2+, Pb2+, Cd2+, Ca2+, Mg2+, Fe2+ does not interfere with the determination of Hg2+. The presented results indicate that the obtained chemosensor is promising as a selective and highly sensitive fluorescent reagent for Hg2+ ions in an aqueous solution.