| New water soluble thiosemicarbazone ligands, namely 3-(3-{[(aminocarbonothioyl) hydrazono]methyl}-4-
hydroxybenzyl)-1-methyl-1H-imidazol-3-ium chloride (H2L1Cl), 3-[4-hydroxy-3-({[(methylamino)
carbonothioyl]hydrazono}methyl)benzyl]-1-methyl-1H-imidazol-3-ium chloride (H2L2Cl) and 3-(3-
{[(anilinocarbonothioyl)hydrazono]methyl}-4-hydroxybenzyl)-1-methyl-1H-imidazol-3-ium chloride (H2L3Cl)
were synthesized through 1:1 condensation reaction of thiosemicarbazide derivatives with 3-(3-formyl-4-
hydroxybenzyl)-1-methyl-1H-imidazole-3-ium chloride (SalimiCl) and characterized by elemental analysis and
spectroscopic methods (UV–Vis, 1
H NMR, FTIR). Single crystals of H2L1Cl and H2L2Cl were prepared for crystallographic analysis, which showed similar X-ray structures for both ligands with chiral P212121 space group. The
ligands were used for synthesis of the following copper(II) complexes: [Cu(HL1)Cl]Cl, [Cu(HL2)Cl]Cl·H2O, and
[Cu(HL3)Cl]Cl. All complexes were characterized by physico-chemical and spectroscopic methods. The X-ray
structure of [Cu(HL1)Cl]Cl was orthorhombic with Pcba space group while [Cu(HL2)Cl]Cl·H2O was triclinic
with Pī space group. Both complexes were mononuclear, with tridentate ligands in a thione form. All of the studied compounds showed good solubility and stability in water. The measurement of the molar conductance
showed the release of Cl− into solution and substitution of water instead of the coordinated chloride. Among
the studied complexes, only [Cu(HL3)Cl]Cl shows a quasi-reversible redox behavior with its reduction and oxidation peak potentials separated by a value of about 0.120 V (Epc = −0.310 V and Epa = −0.190 V) indicating onestep and one-electron transfer for CuII/CuI
redox couple. The cytotoxic effect of the compounds was measured
using the MTT assay on MCF-7 and K562 cell lines and the results showed that [Cu(HL3)Cl]Cl and H2L3Cl had
lower IC50 values compared to the other compounds. Flow cytometry analysis on the MCF-7 cells showed the apoptosis cell death after treating with the H2L3Cl and [Cu(HL3)Cl]Cl. Also studies of cell cycles confirmed the cell
cycle arrest in G2 phase for H2L3Cl and [Cu(HL3)Cl]Cl |