DNA interactions and cytotoxic studies of cis-platin analogues of substituted 2,2′-bipyridines

Platinum(II) complexes [Pt(4″-fpbpy)Cl2] (1), [Pt(4″-mepbpy)Cl2] (2), [Pt(4″-mpbpy)Cl2] (3) and [Pt(4″-bopbpy)Cl2] (4) {where 4″-fpbpy = 4-(4″-fluorophenyl)-6-phenyl-2,2′-bipyridine, 4″-mepbpy = 4-(4″-methylphenyl)-6-phenyl-2,2′-bipyridine, 4″-mpbpy = 4-(4″-methoxyphenyl)-6-phenyl-2,2′-bipyridine, 4″-bopbpy = 4-(4″-benzyloxyphenyl)-6-phenyl-2,2′-bipyridine} have been synthesized and characterized. The binding strength and binding mode of the complexes with HS DNA (Herring Sperm) have been investigated by absorption titration and viscosity measurement studies. The results have been revealed that the complexes bind to DNA by covalent mode with intrinsic binding constant Kb ranging from 6.05 × 104 M−1 to 3.48 × 105 M−1. The unwinding angle of pUC19 DNA has been evaluated by gel electrophoresis assay. The brine shrimp bioassay has been performed to study the in vitro cytotoxic properties of the synthesized metal complexes.

Graphical abstractIncreasing the absorbance shows square planar complexes of Pt(II) binding to the DNA via covalent mode.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of Pt(II) complexes with bipyridines. ► Characterization by IR, UV–visible, TGA and mass spectrometry. ► All Pt(II) complexes have been tested for their cytotoxic studies. ► The interaction of complexes with DNA has been performed.