Kinetics, mechanism and equilibrium studies on the substitution reactions of Pd(II) in reference to Pt(II) complexes with bio-molecules

• An overview of the research in the field of kinetics and mechanisms of substitution reactions of Pd(II) complexes with sulfur and nitrogen donor bio-molecules, is presented.
• The structure-reactivity relationship of Pd(II) complexes is discussed.
• To improve the understanding of the mechanism of action of Pd(II) complexes as analogues to Pt(II) complexes that are potential anti-tumor drugs in the human body.
• Interactions of Pd(II) complexes with sulphur and nitrogen bio-molecules are covered in detail.

An overview of the research in the field of kinetics and mechanisms of substitution reactions of Pd(II) complexes with sulfur and nitrogen donor bio-molecules is presented here. Pd(II) complexes are often used in research projects as a model for Pt(II) complexes since their behavior in solution is very similar. The most important difference is that Pd(II) complexes react 103–105 times faster than the corresponding Pt(II) complexes. The goal of this review is to correlate kinetic, thermodynamic and structural properties of Pd(II) complexes throughout their interaction with biologically relevant molecules. The first part of this review describes the synthesis and structure of some Pd(II) complexes. In addition, the results obtained for substitution reactions of Pd(II) complexes with different sulfur and nitrogen donor bio-molecules under various experimental conditions (pH, ionic strength, temperature, pressure, micelles, ionic liquids) are presented. Furthermore, over the past few decades the anti-tumor activity of some Pd(II) complexes has been demonstrated, which has increased the interest in understanding the mechanism of interaction of Pd(II) complexes with bio-relevant molecules. These studies can contribute to a better understanding of the behavior of these complexes in biological systems and to improve their anti-tumor activity.