Synthesis of binuclear platinum(II) organometallic complexes as potential cross-linking reagents

A series of new organometallic binuclear platinum(II) complexes of the type [PtMeCl(Me2SO)2(μ-NN)] (NN = H2N(CH2)nNH2 with n = 4, 6, 8, 10, 12; 4,4′-bipyridyl and 1,2-bis(4′-pyridyl)ethane) was synthesized and characterized through elemental analysis, 1H and 13C NMR spectroscopy. The interaction of the mononuclear model complex [PtMeCl(Me2SO)(BunNH2)] and of the binuclear complex [PtMeCl(Me2SO)2(μ-H2N(CH2)6NH2] with different nucleosides was investigated by 1H NMR spectroscopy, revealing a binding preference toward N7 position in inosine and guanosine and N3 in cytidine. Thymidine and uridine are not reactive under the same experimental conditions. Gel electrophoresis experiments indicated that the binuclear complexes containing bridging diamines are able to induce significant conformational changes in the supercoiled form of pUC19 plasmid.