Substitution Reactions on Pd(II) L-Histidine-diaqua Complexes: Comparative View from Chloride to Nucleobases and Dinucleotides

Abstract The substitution reactions on cis-[Pd(L-Histidine)- (H2O)2 ]2 + by chloride, adenine, guanosine, adenosine, 5 -GMP, 5'-AMP, 3-AMP, d(ApG) and d(GpA) has been studied at pH = 1.0-3.0 at different temperatures. The study at physiological pH had to be avoided due to undesired polymerization reactions. The results indicate a certain degree of unsensitivity of the substitution reactions by purine based ligands at this low pH when compared with other published studies. In particular, no cooperative effect is observed in the 5'-monophosphates and N(7)adenine and N(7)guanine are found to react at the same rate within experimental error. Results agree with the published values for similar systems and differences for the 5'- and 3'-monophosphates are detected both in the monophosphates and in the dinucleotides.