REACTION-KINETICS OF MACROCYCLIC SILVER(II) COMPLEXES .1. ACID AQUATION OF THE [AG(II)([15]ANEN4)]2+ CATION AND ITS REACTION WITH PEROXODISULFATE

The decomposition kinetics of the [Ag(II)L]2+ cation (where L = [15]an eN4) has been studied as a function of [H+] and temperature, in aqueou s perchlorate media (ionic strength = 1.00 mol dm-3). The decompositio n follows the second-order rate, law, Rate = k[H+][Ag(II)L2+], where k = (6.65 +/- 0.11) x 10(-6) dm3 mol-1 s-1 at 298.2 K. From the tempera ture dependence, an activation energy of 89.0 +/- 0.7 kJ mol-1 has bee n determined. The silver(II) complex reaction with peroxodisulphate ha s also been studied in aqueous perchlorate media. This second-order re action has an activation energy of 45.6 +/- 3.4 kJ mol-1. The mechanis m may be described by reactant ion-pairing followed by a rate-determin ing step involving silver(II) complex-assisted peroxo-bond fissure.