Synthesis, characterization, crystal structure and cytotoxic properties of thiosemicarbazide Ni(II) and Zn(II) complexes

• The new thiosemicarbazone complexes are solved structurally for the first time.
• The in vitro cytotoxic activities of new compounds are studied against MCF-7.
• Thiosemicarbazone exhibits good cytotoxic activity.

Synthesis of new complexes of Ni(II) (1) and Zn(II) (2) with [1-(2-hydroxy-3,5-diiodobenzylidene)-4-phenylthiosemicarbazide] have been reported. The composition of these two complexes 1 and 2 is discussed on the basis of IR, 1H NMR and UV spectral data along with their X-ray crystallographic data. The crystal structure of these two complexes has revealed that the free ligand (L) is deprotonated twice at the oxygen and sulfur atoms and they are coordinated with the complexes through phenoxide-O, azomethine-N and thiolate-S atoms. The single-crystal X-ray structures of complex (1) exhibits a square planar structure, while complex (2) reveals trigonal bipyramidal distorted square based pyramidal structure. Anticancer activity of ligand and the complexes 1–2 are evaluated in human adenocarcinoma (MCF-7) cells. The preliminary bioassay indicates that the free ligand and the complexes 1–2 exhibit inhibitory activity against the human adenocarcinoma cancer cell lines.

The crystal structure of [Ni(L)(PPh3)] (1) and [Zn(L)(bpy)] (2) complexes (L = thiosemicarbazone formed by condensation reaction of N(4)-phenylthiosemicarbazide with 3,5-diiodo salicylaldehyde) have unequivocally showed that the geometry of the nickel(II) complex is a square planar and that of zinc(II) complex is a trigonal bipyramidal distorted square based pyramidal geometry with the thiosemicarbazone bind to the metal as dianionic tridentate ligand through the phenolato oxygen (O), azomethine nitrogen (N) and thiolate sulfur (S). These two complexes has been prepared and screened for their cytotoxic activities against MCF-7 (Human non-metastatic mammary gland adenocarcinoma) cancer cell lines. The ligand has been found to be selectively active against MCF-7 cell line with an IC50 value 25 (μg/mL).Figure optionsDownload as PowerPoint slide