Synthesis, characterization, interaction with DNA and cytotoxicity in vitro of dinuclear Pd(II) and Pt(II) complexes dibridged by 2,2'-azanediyldibenzoic acid.

The dinuclear complexes [Pd(2)(L)(2)(bipy)(2)] (1), [Pd(2)(L)(2)(phen)(2)] (2), [Pt(2)(L)(2)(bipy)(2)] (3) and [Pt(2)(L)(2)(phen)(2)] (4), where bipy=2,2'-bipyridine, phen=1,10-phenanthroline and L=2,2'-azanediyldibenzoic dianion) dibridged by H(2)L ligands have been synthesized and characterized. The binding of the complexes with fish sperm DNA (FS-DNA) were investigated by fluorescence spectroscopy. The results indicate that the four complexes bound to DNA with different binding affinity, in the order complex 4>complex 3>complex 2>complex 1, and the complex 3 binds to DNA in both coordination and intercalative mode. Gel electrophoresis assay demonstrates the ability of the complexes to cleave the pBR 322 plasmid DNA. The cytotoxic activity of the complexes was tested against four different cancer cell lines. The four complexes exhibited cytotoxic specificity and significant cancer cell inhibitory rate.