Research Abstract- February 2009

Platinum complexes have been known for their activity against cancer, being cisplatin ( cis-[PtCl₂(NH₃)₂])  the most widely used drug of this group.  Even though cisplatin is used to treat the disease, it shows a wide number of side effects and a limited spectrum of activity.  Efforts have been made to reduce the toxicity and increase the activity by synthesizing platinum analogues which vary in the usage of leaving groups and ammine ligands.  As a result, the drugs carboplatin and oxaliplatin were developed.  The main goal of this project is to prepare complexes of the type cis-[PtCl₂(NH₃)(L)], in which the replacement of hydrogen (H) atoms by methyl groups in the ligand (L) thiazole is expected to result in a more stable drug by sterically hindering the approach to the Pt atom.  The complex cis-[PtCl₂(NH₃)(thiazole)] (1),was prepared by the direct reaction of an aqueous solution of K[PtCl₃(NH₃)] with ethanol solution of thiazole in a 1:1 molar ratio. The complex was characterized by ¹H nuclear magnetic resonance (500 MHz, in DMF-d₇), Raman spectroscopy, infrared spectroscopy, and elemental analysis. The aromatic protons of ligands in the complex show downfield shifts, which indicate the removal of electron density as a result of the coordination to platinum.   The broad signals at 4.47 ppm that integrated to three correspond to NH₃, confirming the mixed-ligand nature of these complexes.  The Raman spectra of the complexes were obtained, and the characteristic stretching Pt-Cl bands (around 330cm^-1) and Pt-NH₃ bands (around 514cm^-1) were present.  Elemental analysis of (1) confirms the purity of the product: C, 9.87% (theoretical, 9.78%) and H, 1.50% (1.64%). The IR spectra also demonstrate the mixed-amine nature of the complexes:  vibrations due to the NH₃ ligand are present (e. g. 3270 and 3183 cm^-1, N-H symmetric stretching) as well as bands due to thiazole.  The spectral studies confirm that the synthesis was successful, and the product mainly consists of the desired cis-[PtCl₂(NH₃)(thiazole)] complex.  The synthesis of new complexes with methyl derivatives of thiazole is in progress.