Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1396049 | European Journal of Medicinal Chemistry | 2011 | 10 Pages |
Here we present the synthesis of the new Ni(II) complexes with chelating ligands 1-benzothiazol-2-yl-3,5-dimethyl-1H-pyrazole (a), 5-(2-hydroxyphenyl)-3-methyl-1-(2-pyridylo)-1H-pyrazole-4-carboxylic acid methyl ester (b) and 1-benzothiazol-2-yl-5-(2-hydroxyphenyl)-3-methyl-1H-pyrazole-4-carboxylic acid methyl ester (c). These ligands a–c create solid complexes with Ni(II). The crystal and molecular structures of two complexes were determined by X-ray diffraction method. Thermal stability of two complexes with ligand c by TG/DTG and DSC methods were also shown. Cytotoxic activity of all the complexes against three tumour cell lines and to normal endothelial cells (HUVEC) was also estimated. Complexes with ligand c exhibited relatively high cytotoxic activity towards HL-60 and NALM-6 leukaemia cells and WM-115 melanoma cells. Cytotoxic effectiveness of one of these complexes against melanoma WM-115 cells was two times higher than that of cisplatin. The protonation constant log K = 9.63 of ligand b corresponding to the phenol 2-hydroxy group has been determined in 10% (v/v) DMSO/water solution (25 °C). The coordination modes (formation of two monomeric species: NiL and NiL2) in the complexes with Ni(II) are discussed for b on the basis of the potentiometric and UV/Vis data.
Graphical abstractNew Ni(II) complexes with chelating ligands: 1-benzothiazol-2-yl-3,5-dimethyl-1H-pyrazole (a), 5-(2-hydroxybenzo-2-yl)-3-methyl-1-(2-pyridinyl)pyrazol-4-carboxylic acid methyl ester (b) and 1-(2-benzothiazo-2-yl)-5-(2-hydroxyphenyl)-3-methyl-1H-pyrazol-4-carboxylic acid methyl ester (c) have been synthesized and characterized. Cytotoxic activity of their complexes 1a–c, 2a–c and 3c on tumour and normal cells are also shown.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► X-ray crystal structures of Ni(II) complexes pyrazole-derived ligand. ► The complexing properties of pyrazole ligand b with Ni(II) in solution were examined. ► Cytotoxic effect of Ni(II) complexes against tumour and normal cells. ► Complex 1c showed higher cytotoxicity than cisplatin against melanoma WM-115 cells.