title: Kinetics of formation and dissociation of aquocobalt(III) complexes with some carboxylic acids in acid perchlorate solution.
abstract: The rates of formation and dissociation of monocarboxylic complexes of aquocobalt(III) cations with propionic, malonic, and 2-ethylmalonic acids have been measured with the stopped-flow method over a range of concentrations and temperatures in acid perchlorate media at an ionic strength 3.0 M. Although the rate constants for reactions of CoOHaq2+ with neutral ligands cover only a small range, indicating a dissociative mechanism, the associated activation parameters change cooperatively. These variations are discussed in terms of differences in the structure, proton distribution, and rates of water loss in the ion-pair precursors for the different ligands. Similar activation enthalpies of dissociation indicate a common mode of coordination, and the positive activation entropies for dissociation are consistent with a neutral leaving group.
authors: Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115-5000, USA. g.davies@neu.edu
authors: Geoffrey
authors: G
authors: Davies