Time-dependent interactions of platinum(II) complexes with 5'-GMP under simulated physiological conditions studied by capillary electrophoresis

The binding behaviour as well as the time-dependent reaction of five platinum(II) complexes with 5'-GMP have been investigated by capillary electrophoresis under simulated physiological conditions referred to chloride concentration, pH and temperature. Different amine ligands influenced the binding properties towards 5'-GMP and resulted in different half-times of the overall reaction. Complexes with bidentate ligands reacted faster with the monophosphate compared to complexes with monodentate ligands. Complexes consisting of two monodentate hydroxyethylamine ligands reacted very slowly owing to a competitive intramolecular reaction of the hydroxyethyl residues, which was proven by NMR investigations. Reducing the number of hydroxyethyl residues increased the half-times of the reactions. Moreover, the major adducts formed with 5'-GMP were identified by MALDI-MS analysis.