Palladium(II) and platinum(II) oxamate complexes as potential anticancer agents: Structural characterization and cytotoxic activity

摘要

The cytotoxic activity against human carcinogenic cells of five compounds, three of them containing palladium(II) and one containing platinum(II) was evaluated for the first time. These compounds were synthesized and characterized and present the formula K_2(H_2opba)?2H_2O (1), K_2[Pd(opba)]?2H_2O (2), [Pd(NH_3)_4]Cl_2?2H_2O (3), [Pd(NH_3)_4][Pd(opba)] (4) and [Pt(H_2opba)]?H_2O (5), where opba = 1,2-phenylenebis(oxamate). Compounds 4 and 5 are novel and their synthesis and characterization are discussed in detail in this paper. The crystal structure of 4 was elucidated by single crystal X-ray diffraction and consists of discrete [Pd(NH_3)_4]~(2+)cations interacting via hydrogen-bonds with [Pd(opba)]~(2-) anions. Despite the fact that compound 1 has no significant effect on the growth of chronic myelogenous leukemia cells, its Pd~(II) and Pt~(II) complexes inhibit cellular growth in the following order of activity 2 ~ 4 > 5. Compounds 2 and 4 are approximately 20 times more cytotoxic against leukemia cells than the free ligand.