The hydrolysis products of cis-diamminedichloroplatinum(II) 7. The rate of the hydrogen isotope exchange reaction

Abstract

The rate of the NH → ND exchange reaction for cis-PtCl 2(NH 3) 2, PtCl 2(en) and PtCl 2(tn) has been measured in succinate buffered D 2O. Samples of the complex were precipitated as the HgCl 2 adduct, at various times, and the extent of deuteration was estimated by IR spectroscopy. The rate of the reaction is proportional to the [OD −] and activation parameters for the three complexes ( I=0.1 M NaCl, 25.0 °C) in the order (NH 3) 2, (en), (tn) are: 10 4 k ex (M −1 s −1) = 135, 51.4, 3.64; ΔH ≠ (kJ mol −1) = 24.9, 21.2, 50.0; ΔS ≠ (J K −1 mol −1) = −44.1, −64.6, + 10.2.