A multinuclear NMR approach has been taken to study the metal ion binding sites of cis-[Pt(NH3)2Cl2] and trans-[Pt(NH3)2Cl2], to several methylated nucleosides. 1H and 13C NMR provide an indirect method of monitoring the platination site, whereas 15N NMR provides a more direct probe. Mass spectroscopy (FAB) was employed to deterrnine if the metal ion-complex was a mono or bis methyl nucleoside adduct. All of the purine and pyrimidine bases formed bis adducts with the exception of the reaction between cis-[Pt(NH3)2Cl2] and 1-methyladenosine, which formed a mono adduct.
The cis-[Pt(NH3)2Cl2] and the trans-[Pt(NH3)2Cl2] complexes were found to bind the N-7 position of 1-methylguanosine. The 7N-methylguanosine did not react with either the cis- or trans-[Pt(NH3)2Cl2]. Cis-[Pt(NH3)2(NO3)2] and trans-[Pt(NH3)2(NO3)2] were found to bind the N-1 position of 3-methyluracil and 3-methylcytosine.