Structure-cytotoxicity relationship for different types of mononuclear platinum(II) complexes with 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine.

To compare the in vitro cytotoxicity of platinum(II) complexes with 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp), three complexes were prepared: cis-[PtI(2)(dbtp)(2)] (1), cis-[Pt(NO(3))(2)(dbtp)(2)] (2) and cis-[Pt(C(4)H(4)O(5))(dbtp)(2)] (3). The coordination compounds have been structurally characterized by IR; (1)H, (13)C, (15)N, (195)Pt NMR and single-crystal X-ray diffraction (1). Spectroscopic studies reveal the monodentate coordination of the heterocycle ligand (dbtp) via N(3) to platinum(II) ions. In addition, the crystal structure of (1) shows that the platinum(II) ion is located in nearly square-planar PtI(2)N(2) environments with two heterocycle ligands (dbtp) arranged in a head-to-head orientation. The complexes have been screened for their cytotoxicity against two human cells: non-small cell lung carcinoma (A549) and breast cancer (T47D). All of the complexes demonstrated a significant antiproliferative activity against both cell lines. On the basis of these results, it is concluded that the cytotoxicity of the studied compounds against T47D follows the order: (3)<(1)<(2).