New palladium and platinum complexes with bioactive 3,5-diacetyl-1,2,4-triazol bis(4-cyclohexyl thiosemicarbazone) ligand: chemistry, antiproliferative activity and preliminary toxicity studies?

Dalton Transactions Pub Date: 2012-08-21 DOI: 10.1039/C2DT31199B

Abstract

The preparation and characterization of the new 3,5-diacetyl-1,2,4-triazol bis(4-cyclohexyl thiosemicarbazone) ligand, H55L11, is described. Treatment of H55L11 with K2PtCl4 gave the dinuclear complex [Pt(H3L1)]2, 1, but using MCl2(PPh3)2 where M = Pd or Pt, mononuclear complexes 2 and 3, of general formula [M(H3L1)PPh3], were obtained. Subsequent reaction of the [Pd(H3L1)PPh3] complex with PdCl2(PPh3)2 yielded a new dinuclear complex [(PPh3)Pd(H2L1)PdCl], 4. All compounds have been characterized by elemental analysis and FAB+ spectrometry and by IR and NMR spectroscopy. The molecular structures of mononuclear complexes 2 and 3 and dinuclear complex 4 have been determined by X-ray crystallography. The new compounds synthesized have been evaluated for antiproliferative activity in vitro against NCI-H460, HepG2, MCF-7, A2780 and A2780cisR human cancer cell lines. The cytotoxicity data suggest that the H55L11 ligand and [Pt(H3L1)]2, complex 1, may be endowed with important cytotoxic properties since they are capable of not only circumventing cisplatin resistance in A2780cisR but also exhibit antiproliferative activity in NCI-H460. The interactions of these compounds with calf thymus DNA were investigated by UV-vis absorption and a nephrotoxic study, in LLC-PK1 cells, has also been carried out.

Graphical abstract: New palladium and platinum complexes with bioactive 3,5-diacetyl-1,2,4-triazol bis(4-cyclohexyl thiosemicarbazone) ligand: chemistry, antiproliferative activity and preliminary toxicity studies
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