3,5-diacetyl-1,2,4-triazol bis(4N-substituted thiosemicarbazone) palladium(II) complexes: synthesis, structure, antiproliferative activity and low toxicity on normal kidney cells.

Treatment of (4)N-monosubstituted bis(thiosemicarbazone) ligands of 3,5-diacetyl-1,2,4-triazol series with lithium tetrachloridopalladate gave the dinuclear complexes of general formula [Pd(μ-H(3)L(1-5))](2), but using dichloridobistriphenylphosphinepalladium(II) salt, the first mononuclear bis(thiosemicarbazone)-palladium-triphenylphosphine complexes of the 3,5-diacetyl-1,2,4-triazol series, [Pd(H(3)L(1-5))PPh(3)], have been obtained. All the compounds have been characterized by elemental analysis and by IR and NMR spectroscopy, and the crystal and molecular structures of dinuclear complexes [Pd(μ-H(3)L(3))](2) and [Pd(μ-H(3)L(5))](2) as well as mononuclear complexes [Pd(H(3)L(1))PPh(3)], [Pd(H(3)L(2))PPh(3)], [Pd(H(3)L(3))PPh(3)] and [Pd(H(3)L(4))PPh(3)] have been determined by X-ray crystallography. The new compounds synthesized have been evaluated for antiproliferative activity in vitro against NCI-H460, A2780 and A2780cisR human cancer cell lines. Subsequent toxicity study, on normal renal LLC-PK1 cells, shows that all compounds investigated exhibit very low toxicity on kidney cells with respect to cisplatin.