A Comparative Study on the Kinetics and Mechanism of Silver and Mercurous Ion Catalysed Aquation of Chloro and Bromo-(Ethylenediamine)-( Diethylenetriamine)Cobalt(III) Cations

Department of Chemistry, University of Kashmir, Srinagar-190 006 Manuscript received 22 December 1982, revised 24 June 1983, accepted 3 December 1983 The kinetics of Ag+ and \(Hg^{2+}_2\) assisted aquations of [Co(en)(dien)X]2+ (X=Cl, Br ; en=ethylenediamine, dien=diethylenetriamine) have been studied spectrophotometrically over a range of temp at constant рH and ionic strength. The kinetics obey the rate law - dln[complex]/dt = kK(Mn+]/(1+K[Mn+]) (Mn+=Ag+, \(Hg^{2+}_2\)) The reactions involve a bridged transition state. Activation parameters, the formation equilibrium constant of the adduct (K) and the first order rate constants for its dissociation (k) have been calculated. The rate of aquation of the bromo complex is faster than that of the chloro complex. On the basis of the results a mechanism of reaction is suggested