Dihaloplatinum(II) complexes having diimine ligands: crystal structure, thermal properties, cytotoxicity effects against breast cancer cells and application as a precursor towards nanoparticles

Abstract

The reaction of potassium tetrachloroplatinate(II) with dimethylsulfide and a mixture of HBr/KBr affords trans-[PtBr₂(SMe₂)₂]; [PtBr₂(Me₂bpy)] (Me₂bpy = 4,4'-dimethyl-2,2'-bipyridine) was prepared from the reaction of trans-[PtBr₂(SMe₂)₂] with Me₂bpy. The crystal structure of the yellow form of [PtBr₂(bu₂bpy)] (bu₂bpy = 4,4'-di-tert-butyl-2,2'-bipyridine) was determined by X-ray crystallography. The X-ray single-crystal structure determination of complex [PtBr₂(bu₂bpy)] reveals that the platinum adopts a square planar geometry with a twofold axis through the platinum atoms. Thermal properties of the related series of diimine platinum(II) complexes [PtX₂(bu₂bpy)] (X = Cl, Br, I) reveal that the thermal stabilities increase [PtI₂(bu₂bpy)] < [PtCl₂(bu₂bpy)] < [PtBr₂(bu₂bpy)]. [PtBr₂(bpy)] (bpy = 2,2'-bipyridine), [PtBr₂(Me₂bpy)] and [PtX₂(bu₂bpy)] (X = Cl, Br, I) were studied by MTT assay against two human breast cancer cell lines of MCF-7 and MDA-MB-468 with [PtCl₂(bu₂bpy)] having a higher cytotoxic effect towards both cancer cell lines, which shows the significant role of the halide and diimine ligand. Semi-spherical Pt(0) nanoparticles (NPCs) were prepared by the simple calcination of [PtX₂(bu₂bpy)] (X = Cl, Br, I) at 800 °C in air.

Graphical Abstract

Keywords:

• Platinum
• crystal structure
• thermal properties
• breast cancer
• nanoparticle

Acknowledgments

We would like to thank the Research Council of K.N. Toosi University of Technology for financial support.

Disclosure statement

No potential conflict of interest was reported by the authors.