A series of complexes PtAm2L [where Am2=(NH3) 2, ethylenediamine (en), 1, 2- diaminocyclohexane (DACH) or (NH3)(c-C6H11NH2) and where L is a bidentate 1, 1- dicarboxylate ligand tethered to 1-aminoanthraquinone by various spacers] was prepared and screened in vitro against P388 leukemia cells. The free ligands displayed moderate activity and the corresponding platinum complexes were tenfold more active. The nature ...