Ligand reactions. Part I. The release of covalent halogen from some cis-aquo- and cis-hydroxo-(halogenoalkylamine)bis(ethylenediamine)-cobalt(III) cations

Abstract

The kinetics for the appearance of halide ions from some cis-aquo(halogenoalkylamine)bis(ethylenediamine)cobalt(III) cations and their corresponding cis-hydroxo-complexes have been investigated in aqueous solutions under different conditions. In acid solutions the reaction is first-order and presumably yields cis-aquo(alkanol-amine)bis(ethylenediamine)cobalt(III) complexes. The reactivities of the corresponding cis-hydroxo-cations in basic solutions are considerably greater. Here second-order kinetics superimposed on a first-order background are observed, and the product contains cis-hydroxo(iminoalkane)bis(ethylenediame)cobalt(III) species. By comparison with the corresponding data on the free halogenoalkylamine ligands, the effects of co-ordination on their reactivity are discussed.