Synthesis, Characterization, Covalent Binding, and Degree of Unwinding of Platinum(II) Bipyridine Complexes

Abstract

The complexes [Pt(3′′‐clpbpy)Cl2] (1) [3′′‐clpbpy = 4‐(3′′‐chlorophenyl)‐6‐phenyl‐2, 2′‐bipyridine], [Pt(4′′‐clpbpy)Cl2] (2) [4′′‐clpbpy = 4‐(4′′‐chlorophenyl)‐6‐phenyl‐2, 2′‐bipyridine], [Pt(3′′‐brpbpy)Cl2] (3) [3′′‐brpbpy = 4‐(3′′‐bromophenyl)‐6‐phenyl‐2, 2′‐bipyridine], and [Pt(4′′‐brpbpy)Cl2] (4) [4′′‐brpbpy = 4‐(4′′‐bromophenyl)‐6‐phenyl‐2, 2′‐bipyridine] were synthesized and characterized. The binding of the complexes with herring sperm DNA (HS DNA) was investigated by absorption titration and viscosity measurements. It was found that the complexes have ability of interaction with DNA by covalent mode. The intrinsic binding constant Kb of the complexes with HS DNA is 8.76 × 104 (1), 9.89 ×104 (2), 1.52 × 105 (3), and 2.31 × 105 (4) M–1. The slight depression in relative specific viscosity was observed, which also attributes to covalent binding of complexes with DNA bases. Gel electrophoresis assay demonstrated the ability of the complexes to unwind negatively supercoiled pUC19 plasmid by 14° (1), 13° (2), 13° (3), and 11° (4). The in vitro cytotoxic property of the synthesized metal complexes was also carried out against brine shrimp bioassay.

A water-soluble Pd(ii) complex with a terpyridine ligand: experimental and molecular modeling studies of the interaction with DNA and BSA; and in vitro cytotoxicity investigations against five human cancer cell lines

“…Some Pd(II) and Pt(II) complexes that bind to DNA via a covalent binding mode showed similar results. [75][76][77] 2.2.4. DNA cleavage studies.…”