Thermodynamics of the interaction of Pd(dmen)(H₂O)₂²⁺ with bio-relevant ligands with reference to the deactivation of metal-based drug by thiol ligands.

Pd(dmen)Cl(2) complex was synthesized and characterized, where dmen=N,N-dimethylethylenediamine. Stoichiometry and stability constants of the complexes formed between [Pd(dmen)(H(2)O)(2)](2+) and various biologically relevant ligands such as amino acids, peptides and dicarboxylic acids are investigated at 25 °C and at constant 0.1M ionic strength. The concentration distribution diagrams of the various species formed are evaluated. The equilibrium constants for the displacement of coordinated ligands as inosine, glycine or methionine by cysteine are calculated. The results are expected to contribute to the chemistry of tumour therapy.