PLATINUM(II) COORDINATION TO N1 AND N7,N1 OF GUANINE - CIS-DDP MODEL CROSS-LINKS IN THE INTERIOR AND SIMULTANEOUS CROSS-LINKS AT THE PERIPHERY AND THE INTERIOR OF DNA

The preparation and characterization of a series of mono-, di-, and trinuclear Pt(II) complexes of 9-methylguanine (9-MeGH) are reported. The compounds contain the guanine heterocycle monoplatinated at N1 and/or diplatinated at N1 and N7. The route to these compounds involves a primary fixation of a (dien)Pt(II) entity to the N7 position, fixation of a second Pt(II) at N1, and subsequent removal of the N7-bound Pt(II) by cyanide. The crystal structure via X-ray diffraction of a representative example, (en)Pt(9-MeG-N1)2.3H2O (4a) is reported: tetragonal system, space group I4(1)/a, a = 16.003 (2) angstrom, c = 32.247 (6) angstrom, V = 8258 (2) angstrom3, Z = 16.