Novel platinum(II) and palladium(II) complexes with cyclin-dependent kinase inhibitors: Synthesis, characterization and antitumour activity Original Research Article

The Pt(II) and Pd(II) complexes of the types cis-[Pt(L1)2Cl2]·H2O (1), cis-[Pt(L2)2Cl2]·3H2O (2), trans-[Pd(L1)2Cl2]·H2O (3), trans-[Pd(L2)2Cl2]·H2O (4), trans-[Pd(L3)2Cl2]·2DMF (5) and trans-[Pd(L4)2Cl2]·2DMF (6) (L1–L4 = cyclin-dependent kinase inhibitors derived from 6-benzylamino-9-isopropylpurine) have been prepared and characterized. The complexes have been studied by elemental analyses, conductivity measurements, ES+ MS, FT-IR, 1H, 13C and 195Pt NMR spectra, differential scanning calorimetry and thermogravimetric analysis. The molecular structures of L1, trans-[Pd(L3)2Cl2]·2DMF (5) and trans-[Pd(L4)2Cl2]·2DMF (6) have been determined by single crystal X-ray analysis. The complexes have been tested in vitro due to their presumable anticancer activity against the following human cancer cell lines: K-562, MCF7, G-361 and HOS. Satisfying results were obtained for the complex 1 with IC50 values of 6 μM acquired against G-361 as well as against HOS cell lines. The lowest values of IC50 were achieved for the complexes 3 and 4 against MCF 7 cell line with IC50 3 μM (for 3) and also 3 μM (for 4).