Low-dimensional compounds containing bioactive ligands. V: Synthesis and characterization of novel anticancer Pd(II) ionic compounds with quinolin-8-ol halogen derivatives

• NH2(CH3)2[PdCl2(XQ)] complexes are characterized (XQ = halogenated quinolin-8-ol).
• Compounds contain N,O-chelate coordinated XQ in cis-[PdCl2(XQ)]− complex anions.
• NH2(CH3)2[PdCl2(XQ)] interacts with DNA by intercalative binding mode.
• Compounds are active against A2780 and cisplatin resistant A2780/CP cell lines.

Three novel palladium(II) complexes, NH2(CH3)2[PdCl2(CQ)] (1) (CQ = 5-chloro-7-iodo-quinolin-8-ol), NH2(CH3)2[PdCl2(dClQ)] (2) (dClQ = 5,7-dichloro-quinolin-8-ol) and NH2(CH3)2[PdCl2(dBrQ)] (3) (dBrQ = 5,7-dibromo-quinolin-8-ol) have been prepared and characterized. Their structures contain square-planar [PdCl2(XQ)]− complex anions in which deprotonated XQ ligands are coordinated to the Pd atoms via the pyridine nitrogen and the phenolato oxygen atoms, other two cis-positions are occupied by two chlorido ligands. Negative charges of these anions are balanced by uncoordinated dimethylammonium cations. Coordination of the XQ ligands to Pd(II) atom was confirmed by the differences in the stretching ν(OH) and ν(CN) vibrations in the IR spectra of ligands and prepared complexes while bands of aliphatic CH and NH stretching vibrations observed in the spectra of 1–3 confirm the presence of dimethylammonium cations in the complexes. The binding of complexes 1–3 to calf thymus DNA was investigated using UV–visible and fluorescence emission spectrophotometry. The fluorescence spectral results indicate that the complexes can bind to DNA through an intercalative mode. The Stern–Volmer quenching constants obtained from the linear quenching plot are in the 1.04 × 104 to 4.35 × 104 M− 1 range. The complexes exhibit significant anticancer activity tested on A2780 cells and cisplatin resistant cell line A2780/CP.

Three square-planar NH2(CH3)2[PdCl2(XQ)] complexes (XQ are halogen derivatives of quinolin-8-ol) were prepared as Pd-analogs of cisplatin. The complexes were studied by IR spectroscopy and diffraction analysis, their binding to DNA was investigated using UV–vis and fluorescence emission spectrophotometry. The complexes exhibit significant anticancer activity tested on A2780 and A2780/CP cell lines.Figure optionsDownload as PowerPoint slide