A highly selective naphthalene-fluorophore salamo-based chemosensor for sequential identification of Cu2+ and S2- ions in water applications

Two new fluorescent chemical sensors, H4L and its L-Cu2+ complex, are reported for the selective detection of Cu2+ and S2- ions in DMF solution, respectively. In the fluorescent switch structure of chemical sensor H4L, the binding of Cu2+ ions in the receptor part leads to the coordination between the completely deprotonated ligand (L)(4-) unit and Cu2++, resulting in fluorescence quenching. S2- was added to the L-Cu2+ complex to turn on the fluorescence of the L-Cu2+ complex. The chemical sensor H4L and its L-Cu2+ complex can possess obvious selectivities for common cations and anions in the micro molar concentration range, so as to quantitatively detect Cu2+ and S2- ions. The interaction of S2- ions with the chemical sensor L-Cu2+ was investigated by fluorescence time response measurement, whereas high resolution mass spectrometry, and fluorescent titration substantiated the stoichiometry between L-Cu2+ and S2- ions. The crystal structure of the L-Cu2+ complex, [Cu2(L)].2CHCl(3) has been determined by X-ray crystallographic analysis. Density Functional Theory (DFT) calculations were performed in order to show the structures and electronic properties of H4L and its L-Cu2+& nbsp;complex. (C)& nbsp;2022 Elsevier B.V. All rights reserved.

Automated summary

Two new fluorescent chemical sensors, H4L and its L-Cu2+ complex, have been developed for the selective detection of Cu2+ and S2- ions in DMF solution. The fluorescence of the L-Cu2+ complex can be switched on by the addition of S2- ions.