The solvolytic aquation and base hydrolysis of cis- and trans-fluorohydroxobis(ethylenediamine)cobalt(III) cations

Abstract

The first-order rate constants for the solvolytic aquation of cis- and trans-fluorohydroxobis(ethylenediamine)-cobalt(III) cations have been determined over a range of temperatures and the Arrhenius parameters calculated. The product isomerises immediately to an equilibrium mixture, so that it is not possible to determine its initial configuration. The kinetics for the replacement, by hydroxide ion, of co-ordinated fluorine in these cations have been studied and the Arrhenius parameters calculated. Here, unlike the case of solvolytic aquations, isomerisation is negligible under the experimental conditions and the stereochemical consequences of the reaction can be determined spectrophotometrically. Both the cis and the trans isomer of the reactant yield approximately 90%cis and 10%trans products directly.