Caracterização estrutural por difração de raios X e estudo de atividade citotóxica de complexos de platina

Abstract

The interest in platinum(II) complexes containing S donor ligands has increased with the aim of synthesizing antitumor drugs having reduced toxicity with respect to cisplatin. We became interested in characterization of platinum(II) complexes with dithiocarbimates and phosphines due to their similarities with the dithiocarbamate compounds, which show good antitumor activity. In this work are presented the results of in vitro cytotoxic activity against B16-F10 melanoma cells and the structural elucidation, by X-ray diffraction, of four new platinum complexes: * [Pt(CH3SO2N=CS2)(dppe)] (PtFDp), * [Pt (C6H5SO2N=CS2)(PPh3)2] .2H2O (PtGTf), * [Pt(4-CH3C6H4SO2N=CS2)(dppe)] .H2O (PtIDp) * [Pt (4-CH3C6H4SO2N=CS2)(PPh3)2] (PtITf), where dppe = bis(1,2-diphenylphosphine)ethane and PPh3 = triphenylphosphine. The complexes crystallize in the centrosymmetric space group, Pbca or P21/n, on the orthorhombic or monoclinic system, with Z=8 or 4. Only, the compound PtFDp not have disorders atoms. In special, (PtGTf) and (PtIDp) crystallize with water solvent, came from recrystallization. All complexes have a distorted square-planar PtS2P2 chromophores. The crystal packing presents weak intra or/and intermolecular interactions as C-H X (X= π, O, S) and the hydrate compounds have interactions involving water. All studies complexes are active for B16-F10 melanoma cells. The most active compounds (PtFDp) and (PtGTf), characterized by DL50, show much lower concentrations than the observed in the reference compound cisplatin. The complex PtGTf is eight times more efficient than cisplatin.