COMPLEXES OF PLATINUM(II) WITH THE POLYMERIC AMINE LIGAND POLYARIDINE

K2[PtCl4], cis-Pt(NH3)2Cl2, Pt(en)Cl2, and Pt(bpy)Cl2 form complexes in aqueous solution with polyaziridine, the polymeric amine ligand -CH2-CH2-NH- (PEI), as investigated by UV/Vis and Pt-195 NMR spectroscopy. The interaction of K2[PtCl4] and Pt(bpy)Cl2 with PEI yields unambiguously "single species" Pt(PEI)4(2+) and Pt(bpy)(PEI)2(2+), respectively. For cis-Pt(NH3)2Cl2 and Pt(en)Cl2, interaction with PEI leads to release of ammonia and ethylenediamine, as detected by N-14 NMR spectroscopy. Several products are obtained in these cases. The kinetics of the formation of Pt(PEI)4(2+) follows a rate law r = k(obs)[PtCl42-)], where k(obs) increases with increasing PEI concentration and decreases with decreasing pH. Pt(II)-PEI complexes containing "free" amine donor groups form mixed Pt(II)-Cu(II) complexes, in which the magnetic interactions are altered, as compared with the Cu(II)-PEI complexes.