The synthesis and chemical characterization of two structurally related platinum(II) and palladium(II) complexes, [M(2,2'-bipyridine)(morpholinedithiocarbamate)]NO₃ or [M(bpy)(mor-dtc)]NO₃, where M = Pt(II) or Pd(II), are described. Studies of anti-tumor activities of these complexes against human cell tumor lines (K₅₆₂) have been carried out. They show 50% cytotoxic concentration (Cc₅₀) values much lower than that of cisplatin. Both of these water soluble complexes have been shown to interact with calf thymus DNA (ct-DNA) using difference absorption-, fluorescence-, and circular dichroism-titration techniques. These studies showed that both complexes exhibit cooperative binding and presumably intercalate in DNA. These complexes unexpectedly denature DNA at very low concentrations (50-100 μM). Several binding and thermodynamic parameters are also described.

Key words: Platinum and palladium antitumor agents; Cytotoxic activity; DNA-Interaction; Fluorescence; Circular dichroism.