Kinetics and mechanism of the complexation of trans-diamminediaquaplatinum(II) with the 6-oxopurine nucleosides inosine and 1-methylinosine in aqueous solution as a function of the pH

HPLC was employed to measure the rate of complexation between trans-(Pt(NH3)2(H2O2)2)2+ with two model nucleobases, inosine and 1-methylinosine, in aqueous solution at 298.2 K and pH = 2.8-9.6. The results, which showed that 2-methylinosine yields only N7-bound complexes, demonstrated the stepwise formation of 1:1 and 1:2 complexes from an excess of the nucleobase with the N7 binding mechanism predominant in 1:1 complexation.