Highly selective probes of copper(II) complexes for sulfide detection and cytotoxicity assay

Abstract

<p>Two probes based on novel Copper(II) complexes were developed in order to obtain H₂S molecular probes with higher selectivity. The molecular structures of the complexes were characterized by ¹H NMR, HRMS, IR and elemental analysis. The interaction of the compounds with biologically important anions and amino acids was determined by UV-vis and Fluorescence titration experiments. Results indicated that the compounds showed the highest binding ability for HS⁻ among studied anions (AcO⁻, H₂PO₄⁻, F⁻, Cl⁻, Br⁻ and I⁻) and amino acids (GSH, HCys and Cys) accompanied by blue shift phenomenon in pure DMSO and aqueous solution. The possible mechanism of host–guest interaction may be that the Copper(II) ion of complex was captured by HS⁻ and free ligand released which showed a remarkable changes in UV-vis absorption. In addition, cytotoxicity of the synthesized compounds was studied on MCF-7 cells. Results indicated that the synthesized compounds had low cytotoxicity over a concentration range of 0–150 µg⋅mL⁻¹, which exhibited that the synthesized probes could be used to detect H₂S <i>in vivo</i>.</p> <p>The probes based on novel copper(II) complexes were synthesized and obtained by the reaction of substituent salicylaldehyde with amine derivatives, and then reacted with Cu(CH₃COO)₂·H₂O, respectively. Investigation on the interference from other species suggested that copper(II) complexes have high selectivity for HS⁻ over other anions (AcO⁻, , F⁻, Cl⁻, Br⁻ and I⁻), followed by the release of the copper ion to give a remarkable increase in UV–VIS absorption in pure DMSO solution and aqueous solution.</p