Synthesis and characterization of potential anticancer platinum(II) and palladium(II) complexes. Infrared, nuclear magnetic resonance studies, structure and binding site determination

Abstract

Interactions of Pd(II) and Pt(II) with (4-amino-2-methyl-5-pyrimidinyl-methylthio) acetic acid (AMMPTA) in aqueous medium (pH = 3.5 and pH = 11.9) resulted in the formation of new complexes which have been characterized by elemental analysis, IR, 1H, and 13C NMR spectroscopic techniques. Platinum (II) is bound to two ligands through sulphur and oxygen donor atoms to form square planar complexes which in H 2O/D 2O mixture (3:2) is a mixture of cis and trans isomers as evident from NMR studies. Palladium(II), on the other hand, seems to bind weakly to the sulfur donor atom. In both Pd(II) and Pt(II) complexes, the amino group seems to be in the form N +--C -l and N +H--O -H at low and high, pH, respectively. A complete assignment of 1H and 13C NMR spectra resonances is presented for both the ligand and the complexes.