pH-Driven preparation of two related platinum(ii) complexes exhibiting distinct cytotoxic properties

Abstract

Reaction of cis-[PtCl₂(DMSO)₂] with the ligand 4-methyl-2-N-(2-pyridylmethylene)aminophenol (Hpyrimol, L^H) in methanol at room temperature produces the complexes [PtCl₂L^H] or [PtClL], under acidic or basic conditions, respectively. The two platinum compounds exhibit distinct DNA-interacting properties, [PtCl₂L^H] showing a higher affinity for the biomolecules. Furthermore, [PtClL] is clearly more cytotoxic than [PtCl₂L^H] in three different cancer cell lines. Solution studies reveal the occurrence of intricate solvation processes generating different aquated/hydroxido species, whose nature depends on the starting metal complex and the pH of the medium.