Cytosine binding in the novel organoplatinum(II) complex [(COD)PtMe(cytosine)](SbF6)

The organoplatinum fragment [(COD)PtMe] (COD = 1,5-cyclooctadiene) binds to cytosine mainly via the N(3) atom in the water-stable organoplatinum complex [(COD)PtMe(cytosine)](+). This is evident from detailed NMR investigations and a crystal structure determination of [(COD)PtMe(cytosine)](SbF6)center dot 0.5H(2)O. In solution the N3 and N1 stereoisomers are observed in a ratio of 1:0.2. Both species were fully characterized from detailed NMR spectroscopy and reveal marked differences from their non-organometallic counterparts.