Novel platinum(II) complexes with dipyridyl containing chelating ligands and their products with the model nucleobases 1-methylthymine and 1-methyluracil

The reactions of [Pt(dpma)(H2O)(2)](2+) (dpma = 2,2 ' -dipyridylmethylamine) and [Pt(dpk)(H2O)(2)](2+) (dpk = 2,2 ' -dipyridylketone) with the model nucleobases 1-methylthymine (1-MeT) and 1-methyluracil (1-MeY) were studied. Reaction products were characterized by Pt-195 NMR spectroscopy and by X-ray structure analysis. The symmetric dpma and dpk diaqua complexes form dinuclear complexes with 1-methylthymine, acting as secondary bridging ligand via its N3 and O4 donor atoms. [Pt-2(dpma)(2)(1-MeT)(2)](ClO4)(2).H2O (5) and [Pt-2(dpk)(dpk . H2O)(1-MeT)(2)](PF6)(2) . 4H(2)O (6) both show a head-to-head arrangement. Biological tests show a significant in vitro antitumor activity of [Pt(dpk)Cl-2] against the human glioma cell line U87.