In Vitro Anticancer Activity of cis-Diammineplatinum(II) Complexes with β-Diketonate Leaving Group Ligands

Five cationic platinum­(II) complexes of general formula, [Pt­(NH3)2(β-diketonate)]­X are reported, where X is a noncoordinating anion and β-diketonate = acetylacetonate (acac), 1,1,1,-trifluoroacetylacetonate (tfac), benzoylacetonate (bzac), 4,4,4-trifluorobenzoylacetonate (tfbz), or dibenzoylmethide (dbm), corresponding, respectively, to complexes 1–5. The log P values and the stabilities of 1–5 in aqueous solution were evaluated. The phenyl ring substituents of 3–5 increase the lipophilicity of the resulting complexes, whereas the trifluoromethyl groups of 2 and 4 decrease the stability of the complexes in aqueous solution. The uptake of 1–5 in HeLa cells increases as the lipophilicity of the investigated complex increases. Cancer cell cytotoxicity studies indicate that 1 and 3 are the least active complexes whereas 2, 4, and 5 are comparable in activity to cisplatin.