Synthesis and characterization of a series of gold(III) complexes with the 4,4′-dimethyl-2,2′-bipyridine ligand: Counterion influence on the cytotoxicity of gold(III) complexes

چکیده مقاله

A series of Au(III) complexes, [Au(4,4′-dmbipy)X₂] ⁺Y^- where X = Cl, Br and Y = [AuCl₄], [AuCl₂], [ClO₄], [AuBr₄], were prepared from the reactions of HAuCl₄·3H₂O/AuBr₃ with 4,4′-dimethyl-2,2′-bipyridine (4,4′-dmbipy) in a mixture of alcohol/CH₃CN. These complexes were characterized by elemental analysis, IR, UV-Vis, ¹H and ¹³C NMR spectroscopy and their structures were studied by the single-crystal diffraction method. The electrochemical behavior of the title complexes were also studied in CH ₃CN and DMSO using cyclic voltammetry. The cationic parts of the complexes are similar, with a bidentate nitrogenous 4,4′-dmbipy ligand and two halide anions attached to a gold(III) center in a square-planar geometry. However, the effect of the anionic parts of the complexes on the cytotoxic properties was evaluated in four cultures, Vero, A431, HeLa and HT-29 by means of an MTT assay. The results illustrate that the anion part plays an important role in the cytotoxicity of relevant compounds in different cell lines. Complexes 1 and 4, with the similar anion part of [AuX₄]^- (X = Cl and Br), displayed good agreement in their anticancer activities toward human cancer cell lines. © 2014 Elsevier Ltd. All rights reserved.