Mixed ligand complexes of <i>cis</i>-dichloroethionineplatinum (II) and <i>cis</i>-dichloroethioninepalladium (II) with substituted pyrimidines

Abstract

Mixed ligand complexes of <i>cis</i>-dichloroethionineplatinum (II) and <i>cis</i>-dichloroethioninepalladium (II) with pyrimidines, viz 2-hydroxypyrimidines hydrochloride, isocytosine, 2-mercaptopyrimidine, 5-aminouracil, 2-thiocytosine, and 2-thiouracil have been synthesised and characterised by elemental analysis, conductivity data, IR, UV, ¹H and ¹³C NMR spectra. Based on the spectral data it is found that ethionine coordinates to the metal ion through sulphur and amino nitrogen, leaving a free carboxylic acid group. 2-Hydroxypyrimidine hydrochloride, isocytosine, 2-mercaptopyrimidine act as monodentate ligands and bind to Pt(ll) and Pd(ll) through N₃, while 5-aminouracil coordinates to the metal ion through the amino (NH₂) group. The 2-thiocytosine and 2-thiouracil however act as bidentate ligands, coordinating to the metal ion through ring nitrogen (N₃) and sulphur.