ChemInform Abstract: Studies on the Reactions of PtCl2en, cis‐Pt(NH3)2Cl2 and Their Aqua Species with Adenosine, Deoxyadenosine and Adenine Using Ion‐Pair HPLC

Abstract

Abstract The reactions of PtCl 2 en or cis -Pt(NH 3 ) 2 Cl 2 and their aqua species with adenine and adenosine were studied by means of ion-pair HPLC. From the chromatograms, it was found that the first binding site of Pt(II) was the N(7) site of adenine under both acidic and neutral conditions. The rates of Pt(II) binding at the (N7) site of adenosine and deoxyadenosine were measured. The rate constants, k 1 , were obtained for the reactions of PtCl 2 en or cis -Pt(NH 3 ) 2 Cl 2 with adenosine and deoxyadenosine at pH 3 and 7 over the temperature range 9–25 °C. The k 1 values were 6.8–7.7 × 10 −4 dm 3 mol −1 s −1 at 25 °C. For the aqua species, the rate of [ cis -Pt(NH 3 ) 2 ClH 2 O] + with adenosine N(7) was measured. The rate constants, k 2 which were found to be smaller than those of hydrolysis, k h , were calculated at pH 3 over the temperature range 25–40 °C. The k 2 value obtained at 25 °C was 1.1 × 10 −2 dm 3 mol −1 s −1 , 15 time larger than k 1 . The activation parameters were also calculated.