The beginning of the use of platinum (II) complexes in the chemotherapy treatment of cancer took place after the discovery of the antitumor activity of cisplatin by Rosenberg in the 60s.[1However, the side effects and cell resistance lead scientists look for new complexes. Ligands play a role in addition to the central metallic species, such as synergism, modulation of the lipophilic and hydrophilic character and lability.
In this work, we have combined N-alkylated piperazine and phenyl substituted 1,3,4-oxadiazole moieties as ligand, and varying the side carbon chain length (figure 1). Piperazine derivatives showed antibiotic and antitumor activities as well 1,3,4-oxadiazole derivatives showed even more antiparasitic, antidepressant and anti-HIV activities.[2] Three new platinum(II) complexes were synthesized using the same conditions as described in figure 1. The complexes were analyzed by IR, NMR 1H, 13C, MS-Maldi, TG, molar conductivity and CHN. The analyses suggested the Pt were coordinated to the sulfur atom of oxadiazole and to the nitrogen of piperazine. For all three complexes, IR spectra showed C=S and C-N shifted, NMR spectra showed N-CH2-N shifted, MS-MALDIpresented 1 [M-C12H26N2]+, 2 [M- C2H6]+, 3 [M-H]+, TG present two mass lost and residue (PtCl2), molar conductivity in DMF showed the neutral and CHN showed values with <5% error.

Cytotoxic assays using tumor cells and non tumor cells are ongoing and IC50 and selectivity will be assessed to help conclusion about structure activity relationship of this complexes, also compared to free ligands.