Speciation studies on the complex formation reactions of [Pd(N,N-diethyl-ethylendiamine)(H2O)2]2+ with some bio-relevant ligands and displacement reaction by mercaptoethylamine.

Pd(deen)Cl2 and Pd(deen)(CBDCA) complexes, where deen=N,N-diethylethylenediamine and CBDCA=1,1-cyclobutanedicarboxylate, were synthesized and characterized by elemental analysis and spectroscopic techniques. The stoichiometry and stability of the complexes formed between various biologically relevant ligands (amino acids, peptides, DNA constituents and dicarboxylic acids) and [Pd(deen)(H2O)2]2+ were investigated at 25 °C and 0.1 M ionic strength. The speciation diagrams of the complexes formed in solutions are evaluated. The mode of coordination of glycylglycine is investigated by spectrophotometric measurements. The equilibrium constants for the displacement of coordinated ligands as inosine, glycine or methionine by mercaptoethylamine are calculated. The results are expected to contribute to the chemistry of antitumour agents.