Synthesis, characterization, DNA interaction, and cytotoxicity of novel Pd(II) and Pt(II) complexes

Abstract

Four complexes [Pd(L)(bipy)Cl]·4H₂O (1), [Pd(L)(phen)Cl]·4H₂O (2), [Pt(L)(bipy)Cl]·4H₂O (3), and [Pt(L)(phen)Cl]·4H₂O (4), where L = quinolinic acid, bipy = 2,2’-bipyridyl, and phen = 1,10-phenanthroline, have been synthesized and characterized using IR, ¹H NMR, elemental analysis, and single-crystal X-ray diffractometry. The binding of the complexes to FS-DNA was investigated by electronic absorption titration and fluorescence spectroscopy. The results indicate that the complexes bind to FS-DNA in an intercalative mode and the intrinsic binding constants K of the title complexes with FS-DNA are about 3.5 × 10⁴ M⁻¹, 3.9 × 10⁴ M⁻¹, 6.1 × 10⁴ M⁻¹, and 1.4 × 10⁵ M⁻¹, respectively. Also, the four complexes bind to DNA with different binding affinities, in descending order: complex 4, complex 3, complex 2, complex 1. Gel electrophoresis assay demonstrated the ability of the Pt(II) complexes to cleave pBR322 plasmid DNA.

Keywords::

• Pd(II) and Pt(II) complexes
• DNA-binding
• cleavage
• cytotoxic effect

Acknowledgements

We gratefully acknowledge support of the National Natural Science Foundation of China (Nos. 20671064 and 20971090), Foundation of Educational Department of Liaoning Province (No. 20060679), Phenom Foundation of Liaoning colleges and universities (No. 2007R30), and Foundation of Liaoning Bai Qian Wan Talents Program (No. 2008921054). We thank Linda Li of Princeton University (USA) for reading and editing the manuscript.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.