SYNTHESIS, CHARACTERIZATION, AND PROPERTIES OF A GROUP OF PLATINUM(IV) COMPLEXES

The synthesis, characterization and antitumor properties of a group of Pt(IV) complexes is presented. The compounds, formed by oxidation of cis-dichlorodiammineplatinum(II) (1) or its cis-dihydroxo analog, were characterized by elemental analysis and IR and 195Pt NMR spectroscopies. EPR studies of aqueous solutions containing the spin trap phenyl-tert-butylnitrone and various Pt(IV) complexes revealed that the compounds are incapable of producing radical species which may in turn cause DNA breakage. Apparently, the antitumor activity of the compunds is due to Pt(IV) binding via ligand displacement to important cellular components or through the ability of the compounds to undergo in vivo reduction to Pt(II) species, which in turn exert their cytotoxic effects in a manner analogous to 1. As a group, the Pt(IV) compounds were significantly less active against L-1210 [mouse] leukemia than the parent Pt(II) complex, 1.