Quantum chemical calculations are employed to examine the interactions of hydrolysis products of cis-[PtCl2(iPram)(Hpz)] with the purine base site of DNA using guanosine as a model reactant. Thermodynamic parameters, electronic structures, bonding characteristics and spectroscopic properties of the resulting complexes are investigated in the framework of density functional theory (B3LYP functional) along with correlation consistent basis sets. Computed results show that these interactions are dominated by electrostatic effects, namely H-bond contributions. Another remarkable finding is that the replacement of amine groups by larger ones accompanies with a moderate reaction between PtII and guanosine.