Heterometallic bridged Pt(II)-Zn(II) complexes: Influence of the substituent in 4´-position in inert terpy ligand on mechanism of interactions of the complexes with biomolecules
Platinum complexes have significant applications in medicine. However, patients often experience a large number of side effects when taking these drugs. While they exhibit rapid efficacy, they also demonstrate toxicity, and resistance commonly develops. One approach to mitigate these unwanted effects is through the synthesis of heteronuclear complexes. In addition to platinum(II), these heteronuclear complexes incorporate another metal that naturally occurs in the human body. The novel heteronuclear complexes [{cis-PtCl(NH3)(μ-4,4´-bipyridyl)ZnCl(terpy-Cl)}] (ClO4)2, [{cis-PtCl(NH3)(μ-pyrazine)ZnCl(terpy-Cl)}(ClO4)2, [{trans-PtCl(NH3)(μ-4,4´-bipyridyl)ZnCl(terpy-Cl)}](ClO4)2 and [{trans-PtCl(NH3)(μ-pyrazine)ZnCl(terpy-Cl)}](ClO4)2, (where terpy-Cl = 4´-cloro-2,2′:6′,2″-terpyridine) were synthesized and characterized. The stability and interaction of heteronuclear complexes with biologically relevant molecules 5´-GMP and GSH were investigated spectroscopically. It was shown that chloride in 4´ position of 2,2´:6´, 2´´-terpyridine has great influence on the stability of complexes. The decrease of electrophilicity of metal centers leads to the higher pKa values and to moderate stability of the complexes at physiological conditions. In the case of all complexes the decomposition was noticed. These complexes without strong independent cytotoxicity can be a starting point in further research in combined treatments with the aim to reduce side effects.
engleski
2024
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keywords: heteronuclear complexes electronic effects, Pt-Zn complexes terpy-Cl ligand